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  1. #1
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    Default Adding 36KW generator to one of two 200A panels

    Hi guys,

    I'm in the process of installing a 36kw diesel generator at my house to supply emergency power to one of my 2 200A breaker panels. I know 36kw sounds like a lot, but I got 3 HVAC single stage heat pump systems (6ton, 4ton and 3ton), so I will only be powering the 200A panel those are all connected to.

    The house was build in the 80's and the 2 200A panels are Square D Q040M200 panels. They unfortunately do not have separate ground and neutral bars as seen here:



    Here's a view of the entire panel before I touched anything (other than ripping out the original feeder):



    And here's what it looks like now after separating the ground and neutral bars:



    As you can see, I had to extend the ground wires to reach the new ground bars. I used wire nuts. Is that ok?

    Also, there were 2 heavy gauge aluminum ground wires that I mounted to a small 3rd ground bar at the top of the cabinet as seen here:



    Another view of the 2 panels. Left panel is untouched and a service panel. Right panel is now a sub-panel being fed from the transfer switch (pic was taken before I had completed the ground and neutral separation)



    The transfer switch is an Asco 185 200A Service Entrance rated. It is all wired up except for the generator:



    View of meter base and transfer switch:



    Here's a rough sketch of how everything is wired at the moment. The only thing this schematic does not show, is the bond between ground and neutral in the transfer switch.



    And finally, here's a listing of the circuits in each panel. Panel 2 is the one behind the transfer switch. There are some heavy hitters in there.



    I of course did get a permit and want to make sure I have all my ducks in a row before I setup an appointment for him to come out and inspect (still waiting on the generator).

    So did I screw anything up? Anything I should change before he comes out?

    Thanks!

    Similar Threads:
    Last edited by Peter Clausen; 09-03-2015 at 12:21 PM.
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  2. #2
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    Default Re: Adding 36KW generator to one of two 200A panels

    You cannot connect the neutrals to the enclosures.

    The feeds to the panels now need to be 4 wire not 3. I didn't look for the bond screws but they need to be removed also.

    - - - Updated - - -

    All the services need to be grouped. You now have one inside and one outside.

    All answers based on unamended National Electrical codes.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jim Port View Post
    You cannot connect the neutrals to the enclosures.
    Appreciate the feedback Jim. Just to be clear, the 200A panel on the left inside the garage is untouched by me. It is still a service panel (not sub panel), so why would I need to change it to a sub panel?

    The feed to the 2nd panel is indeed 4 wire. 3 x 3/0 copper for L1, L2 and Neutral, and #6 bare copper for ground. This is the same gauge used in the original installation going to the grounding rod(s).

    I did remove the bonding screw in the cabinet that was converted to a sub-panel.

    All the services need to be grouped. You now have one inside and one outside.
    Can you explain what you mean by this? What does this entail from a wiring perspective?

    Thanks!


  4. #4
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    Default Re: Adding 36KW generator to one of two 200A panels

    I think you wasted a lot of effort rearranging to create a separate ground bar... your panel appears to have already had that capability with just the addition or removal of the bonding screw. I could be wrong but it is done now.
    What Jim Port said.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jim Luttrall View Post
    I think you wasted a lot of effort rearranging to create a separate ground bar... your panel appears to have already had that capability with just the addition or removal of the bonding screw.
    That's what I thought too when I first started looking at this, but unlike CH panels or newer Square D panels, these from the 80's don't appear to have that ability unfortunately. Sure, there is a bonding screw that can be removed, which I did, but all 4 bars remain physically connected and there did not appear to be any way to get around that. Anyway, that wasn't really that much extra work. The real work was drilling a 2 5/8" hole through the 12" brick wall, installing 2" conduit, and routing the 3 x 3/0 copper + the #6 ground (thus making this a 4 wire feed sub-panel).

    p.s. Seems my replies to you guys are waiting on moderator approval. Hopefully that will go away once I reach a certain post count.


  6. #6
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jim Port View Post
    You cannot connect the neutrals to the enclosures.

    The feeds to the panels now need to be 4 wire not 3. I didn't look for the bond screws but they need to be removed also.

    - - - Updated - - -

    All the services need to be grouped. You now have one inside and one outside.
    Jim,

    What do you think about the possibility that the building could be supplied by two different sources of power at the same time?
    - When the utility power comes back on and the transfer switch has not switched to utility power from the generator due to its delay setting, and if the transfer switch fails to switch back over, or other scenarios.
    - Should there be another transfer switch (automatic disconnect) to the other panel so that the building is supplied from one source only?

    It looks not quite right but I'm trying to figure out why (other than the things you said, I got those too).

    I'm also wondering how the new grounding terminal bars are attached to the enclosure - drilled holes and self-tapping screws, sheet metal screws (sheet metal screws are a no-no), or drilled and through-bolted with nuts (in which case the paint/coating would need to be removed the ensure proper contact, and is the nut a self-locking nut on the back side, etc).

    Also has all the grounding conductors (not all the same size either) in one terminal when there looks to be 3 terminals there.

    Just some small items added to your list.

    Also looks like that wall or earth is at an angle is is cutting across the required working space in front of the meter and the transfer switch.

    And, a non-electrical note, there is (and appears to never have been) a proper depth landing at the bottom of that stair shown in the photo. Combine that with the top landing appearing to not be wide enough (depending if that is a fixed sidelight or an operable door - even if a double door and that is the inactive door ... but the landing should even be as wide as the sidelight too as that is the opening for the door and the entire opening could become a door - while acknowledging that the photo does not show enough to make that determination, only enough to raise the question of it being correct or not).

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    I'm also wondering how the new grounding terminal bars are attached to the enclosure - drilled holes and self-tapping screws, sheet metal screws (sheet metal screws are a no-no), or drilled and through-bolted with nuts (in which case the paint/coating would need to be removed the ensure proper contact, and is the nut a self-locking nut on the back side, etc).
    I used the screws supplies with the ground bar kits to mount them. They were more like small bolts. I was curious about the need to strip the plaint first, but there was no mention of needing to do so in the installation instructions.

    Also has all the grounding conductors (not all the same size either) in one terminal when there looks to be 3 terminals there.
    I do have 2 #12 grounds running into some terminals. None have 3. I have a few (3) #10 grounds that are currently grounded using #12. I will be picking up some #10 for those.

    Also looks like that wall or earth is at an angle is is cutting across the required working space in front of the meter and the transfer switch.
    Yeah, I cut that one shorter than I meant to. I might go ahead and add a single larger horizontal grounding bar in the top of the cabinet and move all grounds to it. That would eliminate that issues and the need to extend the other grounds.

    And, a non-electrical note, there is (and appears to never have been) a proper depth landing at the bottom of that stair shown in the photo. Combine that with the top landing appearing to not be wide enough (depending if that is a fixed sidelight or an operable door - even if a double door and that is the inactive door ... but the landing should even be as wide as the sidelight too as that is the opening for the door and the entire opening could become a door - while acknowledging that the photo does not show enough to make that determination, only enough to raise the question of it being correct or not).
    Here's another pic showing more of the steps. That tree is coming down as that is where the generator will be sitting. Having Miss Utility come out to mark the power lines. I plan to pull the tree out with the roots, but it might mess with the power lines, in which case I go to plan B, which is to grind the stump down instead.




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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Here's another pic showing more of the steps.
    I was referring to the working space in front of the electrical equipment and the landing at the bottom of the stair.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    I used the screws supplies with the ground bar kits to mount them. They were more like small bolts. I was curious about the need to strip the plaint first, but there was no mention of needing to do so in the installation instructions.
    If you used the screws which came with the ground bar kits, and mounted the ground bar kits in places made for adding ground bar kits, then the self-tapping screws which came with the ground bar kits should be all that is required.

    If you mounted the ground bar kits somewhere else, drilled holes, or something else, then, yes, removing the paint may - may - may be necessary (but that is not necessary when installing the ground bar kits in the proper locations with the provided screws).

    I do have 2 #12 grounds running into some terminals. None have 3. I have a few (3) #10 grounds that are currently grounded using #12. I will be picking up some #10 for those.
    I was referring to in the transfer switch where it looks like you have all the grounding conductors in one terminal with the other terminals not being used.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    I was referring to the working space in front of the electrical equipment and the landing at the bottom of the stair.
    Ah ok I see. I'll measure to see what that distance is. I bet it is real close to 4' (hopefully slightly more!)


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    If you used the screws which came with the ground bar kits, and mounted the ground bar kits in places made for adding ground bar kits, then the self-tapping screws which came with the ground bar kits should be all that is required.

    If you mounted the ground bar kits somewhere else, drilled holes, or something else, then, yes, removing the paint may - may - may be necessary (but that is not necessary when installing the ground bar kits in the proper locations with the provided screws).
    So there were no designated holes for installing the ground bars. I drilled and then used the screw/bolts supplied with the kit. I purposely used a smallish bit and it took considerable effort to get the screws started, let alone tightened all the way on. There is a very solid bond between the 2 screws holding each ground bar to the chassis.

    I was referring to in the transfer switch where it looks like you have all the grounding conductors in one terminal with the other terminals not being used.
    Got it. Yes, I did purposely terminate all 3 ground wires to the same lug in order to "fill it up". Those lugs are sized for like 3/0 ground wires and I'm using #6. I don't think they would have snug up properly with just one wire per lug. Perhaps I need to look around for a smaller ground bar for the transfer switch that is more suitable for #6 grounds?

    Really appreciate all the advice and education!


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Jim,

    What do you think about the possibility that the building could be supplied by two different sources of power at the same time?
    - When the utility power comes back on and the transfer switch has not switched to utility power from the generator due to its delay setting, and if the transfer switch fails to switch back over, or other scenarios.
    - Should there be another transfer switch (automatic disconnect) to the other panel so that the building is supplied from one source only?
    There are lots of generator kits sold today that includes a transfer switch and sub panel, all in one, good for maybe 12 circuits. Would they not fall into the same category of potentially supplying power to a home from 2 different sources at once? The home owner basically takes his 12 most important circuits and extend them into said sub-panel, leaving all other circuits in the original panel(s).

    Something like this:




  13. #13
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    There are lots of generator kits sold today that includes a transfer switch and sub panel, all in one, good for maybe 12 circuits. Would they not fall into the same category of potentially supplying power to a home from 2 different sources at once?
    No, because the utility power goes into the transfer switch and is switch back and forth from the house panels to just the 'emergency' panel. When utility power comes back on, that utility power only goes to that transfer, when the transfer switch switches back to utility power, the other panels are energized at the same time that the generator power is disconnected from going past the transfer switch (only utility power or generator makes it past the transfer switch, not both at the same time).

    - - - Updated - - -

    Quote Originally Posted by Peter Clausen View Post
    So there were no designated holes for installing the ground bars. I drilled and then used the screw/bolts supplied with the kit. I purposely used a smallish bit and it took considerable effort to get the screws started, let alone tightened all the way on. There is a very solid bond between the 2 screws holding each ground bar to the chassis.
    Were the screws pointed sheet metal screws with coarse threads (not good), or self-tapping screws with a blunt point and machine screw like threads (good)?

    Got it. Yes, I did purposely terminate all 3 ground wires to the same lug in order to "fill it up". Those lugs are sized for like 3/0 ground wires and I'm using #6. I don't think they would have snug up properly with just one wire per lug. Perhaps I need to look around for a smaller ground bar for the transfer switch that is more suitable for #6 grounds?
    Those terminals were that large for a reason and are marked with the sizes of conductors the terminals are rated for. Sounds like you need to install terminals which are smaller and are rated for the size of conductors you are terminating in them.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Square D clearly identifies the location of the auxiliary ground bars and provides pre-tapped holes. There are raised bumps to help mount the bars. There are typically three locations in the panels.

    The installed neutral bars are not able to be re purposed to ground bars like other brands of panels.

    Jerry , when I saw so much wrong, I just started typing on the tablet and did not even consider the possibility of the dual feed. I may have missed more. I hate to see so much effort put in to making something so wrong.

    All answers based on unamended National Electrical codes.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    No, because the utility power goes into the transfer switch and is switch back and forth from the house panels to just the 'emergency' panel. When utility power comes back on, that utility power only goes to that transfer, when the transfer switch switches back to utility power, the other panels are energized at the same time that the generator power is disconnected from going past the transfer switch (only utility power or generator makes it past the transfer switch, not both at the same time).
    But only some of the utility power goes into the transfer switch, namely the 12 most critical ones. The rest all remain in the original panel, so there will be a period of time where the non-critical circuits are back on utility power while the critical circuits are still on generator power. The only way I see to eliminate that is to feed ALL utility power into a transfer switch. I think most, if not all, transfers switches, will wait a specified period of time after utility power returns, before they switch the load back to utility.

    Were the screws pointed sheet metal screws with coarse threads (not good), or self-tapping screws with a blunt point and machine screw like threads (good)?
    The latter. Fine thread screws with plenty of surface area making contact with the panel.

    Those terminals were that large for a reason and are marked with the sizes of conductors the terminals are rated for. Sounds like you need to install terminals which are smaller and are rated for the size of conductors you are terminating in them.
    Thanks. I'll check with Asco to see if they offer direct fit terminals meant for smaller gauge ground wires.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jim Port View Post
    Square D clearly identifies the location of the auxiliary ground bars and provides pre-tapped holes. There are raised bumps to help mount the bars. There are typically three locations in the panels.
    I'll take another look, but I looked the panel over rather thoroughly and did not find any pre-tapped holes, nor raised bumps. Perhaps those options were only added sometime in the late 80's?

    The installed neutral bars are not able to be re purposed to ground bars like other brands of panels.
    Agreed. I tossed the ones I removed and purchased new Square D ground bar kits, that included mounting screws.


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    Default Re: Adding 36KW generator to one of two 200A panels

    The automatic transfer switches I have dealt with transfer back to utility power immediately (milliseconds) upon the restoration of utility power. There is no appreciable delay although the generator will continue to run for cool down for a short time. Of course there is a transfer delay upon a power failure to allow the generator to reach full speed.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Looking on the Operator Manual that came with my transfer switch, the default delay to transfer back to utility is 5 minutes. The unloaded period (generator cooldown) is an additional 2 minutes.

    Here's the page from the manual discussing delays (among other things):



    The reason for the delay in transferring back to utility is to ensure that the utility is stable. Sometimes during a storm, the utility will come back for a few seconds, or even a minute, only to drop drop back out. By leaving the load on generator power for a full 5 minutes, the likelihood that utility power will drop a 2nd time once the transfer back to utility takes place, is much less.

    I also dug through some other documentation and realized there is a much more elegant method built in to the transfer switch chassis to bond neutral to ground.





    So I'll remove my #6 strap between ground and neutral in favor of this solution.

    Last edited by Peter Clausen; 09-04-2015 at 06:06 PM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    The automatic transfer switches I have dealt with transfer back to utility power immediately (milliseconds) upon the restoration of utility power. There is no appreciable delay although the generator will continue to run for cool down for a short time. Of course there is a transfer delay upon a power failure to allow the generator to reach full speed.
    The ones I've seen had a delay before transferring back to*utility power to allow for false restarts and avoid the transfer switch jumping back and forth.

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    Default Re: Adding 36KW generator to one of two 200A panels

    I had some time yesterday to cleanup the wiring some.

    Here's the revised wiring at the transfer switch:



    Closeup of the ground to neutral bonding bar:



    And the revised ground bar wiring.



    I also redid the ground bar in the sub panel (right one in the below pic). As stated before, I have not touched anything in the left service panel.





    Closeup of ground bar. I put anti oxidation on the 2 aluminum ground wires.



    Another outside shot showing the conduit below the transfer switch that carries the load wires into the garage. Is it ok to have a conduit body below grade?



    Also, I believe I need to use irreversible crimps to extend the #6 ground wire into the transfer switch, as opposed to regular grounding clamps, is that correct?


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    Default Re: Adding 36KW generator to one of two 200A panels

    Also, I believe I need to use irreversible crimps to extend the #6 ground wire into the transfer switch, as opposed to regular grounding clamps, is that correct?[/QUOTE]

    Irreversible something: crimp, weld, or a lug that once tightened can't be loosened--may have a piece that shears off at proper torque.


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    Default Re: Adding 36KW generator to one of two 200A panels

    For Jim Port:

    What is your thinking on where the service disconnect is for generators which are provided with a breaker and have the "service equipment" and "service disconnect" built into the generator?

    That would make the disconnect at the house (the transfer switch) being fed by feeder conductors from the generator instead of being fed by service entrance conductors (from the generator).

    The grounded conductor (neutral) from the generator to the transfer switch would now be isolated from ground and the grounding electrode system.

    The transfer switch enclosure and its grounds and grounding electrode conductor would be connected to the existing grounding electrode system.

    What say you?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    I am going to defer to someone with more generator experience. I have only used the interlocks.

    All answers based on unamended National Electrical codes.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Another outside shot showing the conduit below the transfer switch that carries the load wires into the garage. Is it ok to have a conduit body below grade?]







    It is okay to have a conduit body in e.g. a basement or vault. However, like any other electrical box, it must be installed so as to allow access to and removal of the cover.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    For Jim Port:

    What is your thinking on where the service disconnect is for generators which are provided with a breaker and have the "service equipment" and "service disconnect" built into the generator?

    That would make the disconnect at the house (the transfer switch) being fed by feeder conductors from the generator instead of being fed by service entrance conductors (from the generator).

    The grounded conductor (neutral) from the generator to the transfer switch would now be isolated from ground and the grounding electrode system.

    The transfer switch enclosure and its grounds and grounding electrode conductor would be connected to the existing grounding electrode system.

    What say you?
    i don't understand how the conductors from the generator would be service conductors. The grounded conductors are/or should be bonded to the GEC in the transfer switch.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    i don't understand how the conductors from the generator would be service conductors. The grounded conductors are/or should be bonded to the GEC in the transfer switch.
    The generator will be, should be, on a concrete pad or other supporting structure, and the generator is the power source feeding one side of the transfer switch.

    The utility power source is the other power source which is feeding the other side of the transfer switch (and all of the utility power should be through the transfer switch so that the structure is supplied by one source only - utility power OR generator power - not as you have it connected where the structure can be supplied by two separated sources of power at the same time).

    Let's start off by describing another setup and with utility power as the source:
    - The structure is supplied by utility power to the service equipment on the structure.
    - Another structure (let's say a detached garage) is supplied from the service equipment or from a panel downstream from the service equipment.
    - The service equipment on the structure is supplied by service entrance conductors consisting of 3 conductors - two ungrounded (hot) conductors and one grounded (neutral) conductor, and that grounded neutral conductor is also permitted to be the grounding conductor.
    - - The grounded conductor is required to be bonded to ground at the service equipment.
    - - The grounded conductor is required to be isolated from ground downstream of the load side of the main service disconnect (not permitted to be bonded to the grounding conductor downstream of the service equipment).
    - - All feeders and circuits downstream from the service equipment are required to have conductors - two ungrounded (hot) conductors, one groundED (neutral conductor, grounded at the service equipment), and one groundING conductor to serve as the equipment grounding conductor.
    - The detached garage has a 6 circuit panel so no single main disconnect is required (it is allowed, just not required).
    - - The feeders to the garage have 4 conductors (see above).
    - - The groundING conductor at the panel has an grounding electrode conductor (GEC) which goes from the panel enclosure to the grounding electrodes (Ufer ground, ground rods, building steel, etc., as available).
    - - The groundED conductor at the pane is isolated from the groundING conductor and from the enclosure.

    Now, back to the generator and its structure.
    - The breaker at the generator is the service disconnect.
    - The grounded conductor is bonded to the grounding conductor in the generator service equipment enclosure.
    - The feeders (no service entrance conductors) from the generator to the transfer switch on the house has 4 conductors - two ungrounded (hot) conductors, one groundED (neutral) conductor, and one groundING conductor.
    - The transfer switch is a disconnect for the structure (as is required) which is downstream from the service equipment on the generator and is therefore not acting as the service equipment, thus the groundED conductor needs to be isolated the groundING conductor.

    Now, if your installation instructions shows something different, and the way you wired and connected the generator is precisely as stated in the installation instructions, then the NEC states (in 110.3(B) Installation and Use) that listed and labeled equipment is to be installed and used in accordance with the listing and labeling information, which includes the installation instructions.

    So ... exactly how does your installation instructions state that the generator is to be installed and wired and connected?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    The generator will be, should be, on a concrete pad or other supporting structure, and the generator is the power source feeding one side of the transfer switch.

    The utility power source is the other power source which is feeding the other side of the transfer switch (and all of the utility power should be through the transfer switch so that the structure is supplied by one source only - utility power OR generator power - not as you have it connected where the structure can be supplied by two separated sources of power at the same time).

    Let's start off by describing another setup and with utility power as the source:
    - The structure is supplied by utility power to the service equipment on the structure.
    - Another structure (let's say a detached garage) is supplied from the service equipment or from a panel downstream from the service equipment.
    - The service equipment on the structure is supplied by service entrance conductors consisting of 3 conductors - two ungrounded (hot) conductors and one grounded (neutral) conductor, and that grounded neutral conductor is also permitted to be the grounding conductor.
    - - The grounded conductor is required to be bonded to ground at the service equipment.
    - - The grounded conductor is required to be isolated from ground downstream of the load side of the main service disconnect (not permitted to be bonded to the grounding conductor downstream of the service equipment).
    - - All feeders and circuits downstream from the service equipment are required to have conductors - two ungrounded (hot) conductors, one groundED (neutral conductor, grounded at the service equipment), and one groundING conductor to serve as the equipment grounding conductor.
    - The detached garage has a 6 circuit panel so no single main disconnect is required (it is allowed, just not required).
    - - The feeders to the garage have 4 conductors (see above).
    - - The groundING conductor at the panel has an grounding electrode conductor (GEC) which goes from the panel enclosure to the grounding electrodes (Ufer ground, ground rods, building steel, etc., as available).
    - - The groundED conductor at the pane is isolated from the groundING conductor and from the enclosure.

    Now, back to the generator and its structure.
    - The breaker at the generator is the service disconnect.
    - The grounded conductor is bonded to the grounding conductor in the generator service equipment enclosure.
    - The feeders (no service entrance conductors) from the generator to the transfer switch on the house has 4 conductors - two ungrounded (hot) conductors, one groundED (neutral) conductor, and one groundING conductor.
    - The transfer switch is a disconnect for the structure (as is required) which is downstream from the service equipment on the generator and is therefore not acting as the service equipment, thus the groundED conductor needs to be isolated the groundING conductor.

    Now, if your installation instructions shows something different, and the way you wired and connected the generator is precisely as stated in the installation instructions, then the NEC states (in 110.3(B) Installation and Use) that listed and labeled equipment is to be installed and used in accordance with the listing and labeling information, which includes the installation instructions.

    So ... exactly how does your installation instructions state that the generator is to be installed and wired and connected?
    Paragraph #2. That is exactly how any transfer/ generator installation is configured. That is the purpose of the transfer switch. To prevent two sources from being connected at the same time.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    i don't understand how the conductors from the generator would be service conductors. The grounded conductors are/or should be bonded to the GEC in the transfer switch.
    What's key is that grounding electrode conductors and ground and neutral are all bonded together at one and only one point that is connected to the system at any time.

    We don't want neutral current, for example, to travel from one termination point to another through a cabinet's sheet metal.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Hi Peter,

    Just a couple of observations on your install.

    You should have a separate conduit for control and power to the generator. The A.C. lines can induce voltages into the control wires which are carrying DC. Most generator manufacturers require this. Be mindful that the bock heater (if equipped) should also be in a separate pipe.

    The output from the generator has to be treated as a separately derived source. Most likely the generator will come from the factory with the neutral bonded to the frame. You need to factor that into your installation plans.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    Paragraph #2. That is exactly how any transfer/ generator installation is configured. That is the purpose of the transfer switch. To prevent two sources from being connected at the same time.
    Brad,

    "That is exactly how any transfer/ generator installation is configured."

    Unfortunately, that's not how his is installed.

    His transfer switch only affects one panel, not all power to the structure.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Brad,

    "That is exactly how any transfer/ generator installation is configured."

    Unfortunately, that's not how his is installed.

    His transfer switch only affects one panel, not all power to the structure.
    Right, that's the main challenge with this install. A 400A Service Rated transfer switch lists at almost $9,000, so that was way out of my budget. The 200A Service Rated transfer switch that I'm using instead listed at 1/3 of that.

    All my critical circuits are contained in the single 200A sub panel that I intend to power by the generator.

    Surely is it possible to have 2 200A panels in a single structure with only one of them having an alternate power source AND without having the transfer switch also switch the neutral line?

    The installation manual does not cover the scenario of 2 200A panels, only only there only being a single panel, or a 2nd panel being feed from the first one, which is only applicable up to 100A since that is typically the largest breaker available in a standard 200A panel. I should also point out that the installation manual is pretty generic and covers Asco transfer switches in the range of 100A to 400A, so the main panel feeding a sub panel scenario is really only applicable for the smaller transfer switch sizes.

    What's key is that grounding electrode conductors and ground and neutral are all bonded together at one and only one point that is connected to the system at any time.

    I believe I will be able to pull that off by grounding the meter base from the transfer switch and move the neutral currently running between the meter base and the panel not on the generator, to instead run to the transfer switch. It won't look pretty or be easy, but if that's the only way to do it, that's what I'll do. I'll draw up a sketch later illustrating what I'm talking about.



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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Brad,

    "That is exactly how any transfer/ generator installation is configured."

    Unfortunately, that's not how his is installed.

    His transfer switch only affects one panel, not all power to the structure.
    Totally irrelevant.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    Totally irrelevant.
    Let's see ...

    I am commenting on what is installed.

    You are commenting on what is supposed to be installed.

    I reaffirmed that I am commenting on what IS installed.

    Who is "Totally irrelevant." to the discussion? If anyone is - you are.

    However, stating what 'should be there', as I have already done, and as you did, is pertinent to the discussion, so ... the only thing which is "Totally irrelevant." was that comment of yours.

    But ... I guess you felt you had to say SOMETHING????

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Right, that's the main challenge with this install. A 400A Service Rated transfer switch lists at almost $9,000, so that was way out of my budget. The 200A Service Rated transfer switch that I'm using instead listed at 1/3 of that.
    How about this one?
    - http://www.nationwidegenerators.com/...-single-phase/

    It would remove the entire utility service from the structure, then the generator would be connected only to the panel and circuits you want to have the backup standby generator power.

    I did a Google search for "400 amp automatic service disconnect" and found several in the under-$3,000 price range, and that one is less than $2,000.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Let's see ...

    I am commenting on what is installed.

    You are commenting on what is supposed to be installed.

    I reaffirmed that I am commenting on what IS installed.

    Who is "Totally irrelevant." to the discussion? If anyone is - you are.

    However, stating what 'should be there', as I have already done, and as you did, is pertinent to the discussion, so ... the only thing which is "Totally irrelevant." was that comment of yours.

    But ... I guess you felt you had to say SOMETHING????
    The fact is, if it is properly installed to only one panel, there is NO code violation.


  36. #36
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    Default Re: Adding 36KW generator to one of two 200A panels

    Ok I am going to be blunt:

    1. There is nothing wrong with a single panel being on back up power, this part is fine as is.

    2. Seeing the OPs skill level I would seriously consider getting an electrician involved. Seeing the set up and questions being asked along the way shows me the OP is in over his head. At this point more time money and effort is being spent to do it wrong.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    The fact is, if it is properly installed to only one panel, there is NO code violation.
    Not correct as the structure is only permitted to have ONE service to it, and when the utility power comes back on while the generator is still supplying power to the structure - there are TWO services to the structure ,,, and THAT is a code violation.

    THAT is why the transfer switch needs to disconnect ALL utility power to the structure and then connect only the load the generator is capable of providing.

    Thus, I now understand why YOUR previous post was "Totally irrelevant.", as is your post above.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Not correct as the structure is only permitted to have ONE service to it, and when the utility power comes back on while the generator is still supplying power to the structure - there are TWO services to the structure ,,, and THAT is a code violation.

    THAT is why the transfer switch needs to disconnect ALL utility power to the structure and then connect only the load the generator is capable of providing.

    Thus, I now understand why YOUR previous post was "Totally irrelevant.", as is your post above.
    Read the definition of a "service". A generator is NOT a service.
    Your bullying is not very becoming and you are not always right.


  39. #39
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    Not correct as the structure is only permitted to have ONE service to it, and when the utility power comes back on while the generator is still supplying power to the structure - there are TWO services to the structure ,,, and THAT is a code violation.

    THAT is why the transfer switch needs to disconnect ALL utility power to the structure and then connect only the load the generator is capable of providing.

    Thus, I now understand why YOUR previous post was "Totally irrelevant.", as is your post above.
    A generator is not a service from my understanding.

    Second you can have up to 6 service disconnects, not just one.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Why doesn't the poster get it done properly by a 'qualified' electrician?


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Mbrooke View Post
    Second you can have up to 6 service disconnects, not just one.
    6 service DISCONNECTS ...

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    How about this one?
    - http://www.nationwidegenerators.com/...-single-phase/

    It would remove the entire utility service from the structure, then the generator would be connected only to the panel and circuits you want to have the backup standby generator power.

    I did a Google search for "400 amp automatic service disconnect" and found several in the under-$3,000 price range, and that one is less than $2,000.
    The one you linked to won't work. That one will only work with Generac generators. You see, Generac Transfers switches have no logic inside them, only a switch solenoid that is controlled from the logic that resides within the generator itself.

    This is the least expensive 400A service rated transfer switch I was able to locate that comes with the standard 2-wire "close to run" contacts to start a generator.

    http://www.ebay.com/itm/ASCO-185SE-4...item439b112cb1

    The enclosure for that Asco 400A transfer switch would not fit on the wall next to the existing meter base and inside mounting wasn't really an option either as that would have made the run from the meter base to the service disconnect in the transfer switch longer than 6 feet, which I'm quite certain would fail inspection.

    Last edited by Peter Clausen; 09-10-2015 at 06:29 PM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    THAT is why the transfer switch needs to disconnect ALL utility power to the structure and then connect only the load the generator is capable of providing.
    There are 1,000's of installations (if not 10,000's or 100,000's) around the country where a 100A breaker in a service panel is feeding a transfer switch which in turn feeds a sub-panel containing critical circuits. In all those installations, once the utility power comes back on, the building/structure will be feed from 2 power sources.

    Once the inspector comes out, I promise to post the outcome. Should be interesting.

    Btw, while I know I'm new on this forum, I'm certainly not new to take on projects on my own of pretty much any size, challenge, or difficulty level.

    Here are some examples and for most of them I had no prior experience or knowledge. This is why I think the Internet is awesome for educating one selves and sharing experiences when going into uncharted territory.

    http://www.tractorbynet.com/forums/p...tml?highlight=

    http://www.tractorbynet.com/forums/p...tml?highlight=

    http://www.corvetteforum.com/forums/...pictorial.html

    http://www.m5board.com/vbulletin/e60...pictorial.html

    http://www.m5board.com/vbulletin/e60...g-install.html

    http://www.zukiworld.com/forum/gener...-grand-vitara/

    These are still work in progress:

    http://www.steelsoldiers.com/showthr...ere&highlight=

    http://www.xoutpost.com/bmw-sav-foru...-once-all.html

    Computer A/V stuff:

    http://www.avsforum.com/forum/26-hom...-question.html

    http://www.avsforum.com/forum/26-hom...ne-online.html

    http://www.avsforum.com/forum/155-di...ame-today.html

    https://forums.freenas.org/index.php...2-disks.30431/

    Astronomy:

    http://www.cloudynights.com/topic/11...concrete-pier/

    http://www.cloudynights.com/topic/13...-construction/

    Salt water fish tank:

    http://www.reefcentral.com/forums/sh...d.php?t=589483

    I think I got a little carried away. Sorry.

    Last edited by Peter Clausen; 09-10-2015 at 07:25 PM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    The one you linked to won't work. That one will only work with Generac generators. You see, Generac Transfers switches have no logic inside them, only a switch solenoid that is controlled from the logic that resides within the generator itself.
    Those pesky details matter, don't they?

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    Default Re: Adding 36KW generator to one of two 200A panels

    You need a dual coil contactor with one coil fed from a 15 amp breaker off each panel. If either panel loses powers - the contactor stays on ... however, if both panels lose power, the contactor shuts down.

    The normally open terminals of the contactor are closed when the contactor has power to either coil - transfer switch power sensing conductor goes to the N.O. terminals of the contactor ... as long as there is power, the transfer switch stays at utility power ... when utility power is lost, the contactor opens and that circuit to the transfer switch power sensing conductor is broken and the transfer switch operates - switches to the generator.

    The normally closed terminal of the contractor are open when there is utility power, but close when utility power is lost. The generator starting circuit is run through the N.C. terminals of the contactor, when the contactor loses utility power the generator starts.

    Okay, so there is no 'smart' circuit in there to start the generator before switching the transfer switch to generator, but, hey, the idea is worth at least as much as what you paid for it (nothing ).

    ... back to the days of when I designed lighting systems and stuff for discos ... those were fun times and I got to build whatever I could think up.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Frank Smith View Post
    You should have a separate conduit for control and power to the generator. The A.C. lines can induce voltages into the control wires which are carrying DC. Most generator manufacturers require this. Be mindful that the bock heater (if equipped) should also be in a separate pipe.

    The output from the generator has to be treated as a separately derived source. Most likely the generator will come from the factory with the neutral bonded to the frame. You need to factor that into your installation plans.
    Hi Frank,

    Appreciate the feedback. I have drilled separate holes in the transfer switch enclosure to accommodate the separate conduits for the A.C. lines vs. the D.C. control lines. I have a 2.5" conduit for the A.C. lines and a 1/2" conduit for the control lines. You can just make out those 2 in the below pic which is a snippet from the most recent main transfer switch pic I posted.



    Here's a simplified wiring diagram showing the current relationship between all the ground and neutral lines.



    I think we all agree that if I was to simply erase Service Panel A from the above diagram, everything would be to code as there would only be a single service entrance where neutral and ground are bonded, which would be at the transfer switch.

    So the question is, does anything need to change with regards to the neutral and ground wiring for Service Panel A in order to meet code?

    As stated before, I have not touched Panel A or any of it's wiring at this point, and would prefer not to unless needed.

    For reference, the original neutral and ground was wires as follows:



    Last edited by Peter Clausen; 09-11-2015 at 02:32 AM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Hi Frank,

    Appreciate the feedback. I have drilled separate holes in the transfer switch enclosure to accommodate the separate conduits for the A.C. lines vs. the D.C. control lines. I have a 2.5" conduit for the A.C. lines and a 1/2" conduit for the control lines. You can just make out those 2 in the below pic which is a snippet from the most recent main transfer switch pic I posted.



    Here's a simplified wiring diagram showing the current relationship between all the ground and neutral lines.



    I think we all agree that if I was to simply erase Service Panel A from the above diagram, everything would be to code as there would only be a single service entrance where neutral and ground are bonded, which would be at the transfer switch.

    So the question is, does anything need to change with regards to the neutral and ground wiring for Service Panel A in order to meet code?

    As stated before, I have not touched Panel A or any of it's wiring at this point, and would prefer not to unless needed.

    For reference, the original neutral and ground was wires as follows:

    In most cases, there are no grounding conductors to the meter base. The meter pan is bonded to the neutral.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Brad Richter View Post
    In most cases, there are no grounding conductors to the meter base. The meter pan is bonded to the neutral.
    Here's the meter base before I touched anything. You can clearly see the ground wire connected to the neutral bar, which in turn is bonded to the meter pan. So best practices would be to eliminate this ground?




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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Here's the meter base before I touched anything. You can clearly see the ground wire connected to the neutral bar, which in turn is bonded to the meter pan. So best practices would be to eliminate this ground?

    Depends upon your POCO or AHJ. Perfectly acceptable under NEC.


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    Default Re: Adding 36KW generator to one of two 200A panels

    Thanks. All other meter bases in my neighborhood, all served by the same utility company have the ground wire running up in their meter bases as well, so I suspect they want it.

    I'll make sure to ask the inspector to see if he agrees.

    Last edited by Peter Clausen; 09-11-2015 at 09:30 AM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    Here's the meter base before I touched anything. You can clearly see the ground wire connected to the neutral bar, which in turn is bonded to the meter pan.
    What does it look like now?

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    Default Re: Adding 36KW generator to one of two 200A panels

    Why did you open a meter socket that belongs to the power company? Some will prosecute for tampering with their equipment.

    I doubt that you have the training or protective equipment to be in the socket also.

    There is no issue with not all the circuits being fed from the generator. It would be rare, especially in a house, for all the circuits to be critical and need backup. It also keeps the generator a smaller size. As there is no interconnect between the critical and non-critical panels there is no need for both panels to be isolated from utility power, just the critical panel needs isolation to prevent backfeeding into the grid. I believe this was the concept that was meant when it was said about "irrelevant".

    All answers based on unamended National Electrical codes.

  53. #53
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    Default Re: Adding 36KW generator to one of two 200A panels

    Why did you open a meter socket that belongs to the power company? Some will prosecute for tampering with their equipment.
    It would have been extremely difficult, no make that impossible, to remove the old feeder and installing the new feeder to the transfer switch, without removing the cover and pull the meter.

    When I did the 400A service for my shop, I went to their office and picked up a meter base and completed all the wiring from the base to my panel. I also dug the trench from the pole to the meter base. I also supplied the 3" conduit, and they then came out to drop the feed into the trench and run it up into the meter base through the 3" conduit. I also drove in the ground rods and had everything inspected, and then the power company made everything hot at the pole. I'm on a co-op and they are all "good old boys".

    I doubt that you have the training or protective equipment to be in the socket also.
    Common sense dictate to stay away from the 2 hot wires at the top of the meter base cabinet. I did tape on a rubber mat over the exposed hot terminals after step 4 below AND I wore rubber work gloves while making the changes, even though nothing I touched was hot.

    1. Turn of both main breakers in panel to remove load.
    2. Lift up bypass handle.
    3. Pull meter.
    4. Push down bypass handle.
    5. Check with voltmeter that neither L1 or L2 on the downstream side of the meter socket were hot.
    6. Do what you need to do.
    7. Reverse procedure.
    8. Call power company to come inspect work and put on new seal (waiting until after inspection as he no doubt want to see the work done in the meter base).

    There is no issue with not all the circuits being fed from the generator. It would be rare, especially in a house, for all the circuits to be critical and need backup. It also keeps the generator a smaller size. As there is no interconnect between the critical and non-critical panels there is no need for both panels to be isolated from utility power, just the critical panel needs isolation to prevent backfeeding into the grid. I believe this was the concept that was meant when it was said about "irrelevant".
    Thanks for adding clarity to this, at time, very confusing thread!

    Last edited by Peter Clausen; 09-11-2015 at 10:56 AM.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    What does it look like now?



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    Default Re: Adding 36KW generator to one of two 200A panels

    So the power company came out and marked the power lines (and they did not get their panties all in a twist due to me opening the meter base ). So here's how the power line runs:





    And this is roughly where the generator is going:



    So its going right on top of where that tree is. My preference would be to just pull the tree out, stump, roots and all, but the roots might go down below or close to the power lines.

    There's also this retaining wall to consider:





    So what do you think? Go for it and just pull out the whole tree and hope for the best?

    Or cut the tree flush with the ground and then use a stump grinder to get below grade? I need to come down about 1.5 feet where the stump is in order to prep for the concrete pad. That's a lot of stump grinding....


  56. #56
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    Default Re: Adding 36KW generator to one of two 200A panels

    Or leave the tree ...

    And in the meter can - you need to make sure to close off that opening where the service entrance conductors you removed ... unscrew the lock nut, push the fitting into the wall, and insert a closure plug.

    The conduit coming up out of the ground needs to be sealed to keep moisture from underground out of the meter can and other equipment - use duct seal for that, just pack it down tightly around the conductors and into the end of the conduit as best possible.

    Also wouldn't hurt to use duct seal to seal up the remaining service entrance cable to keep air and moisture from infiltrating into the wall cavity.

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    Default Re: Adding 36KW generator to one of two 200A panels

    Have you checked building code clearance requirements between the generator and house? It looks too close.

    All answers based on unamended National Electrical codes.

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    Default Re: Adding 36KW generator to one of two 200A panels

    This may seem like a dumb question, but what are you going to do for hot water? I noticed neither of the two water heaters are powered by the generator.

    This may also be a dumb question, but why are you bothering with a generator in the first place? Why not just a portable generator for emergencies?


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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Jerry Peck View Post
    And in the meter can - you need to make sure to close off that opening where the service entrance conductors you removed ... unscrew the lock nut, push the fitting into the wall, and insert a closure plug.
    Thanks, I was wondering if I needed to do that and if so how to do it. That advice makes perfect sense. I'll do that.

    The conduit coming up out of the ground needs to be sealed to keep moisture from underground out of the meter can and other equipment - use duct seal for that, just pack it down tightly around the conductors and into the end of the conduit as best possible.

    Also wouldn't hurt to use duct seal to seal up the remaining service entrance cable to keep air and moisture from infiltrating into the wall cavity.
    Thanks, I'll do that as well.

    - - - Updated - - -

    Quote Originally Posted by Jim Port View Post
    Have you checked building code clearance requirements between the generator and house? It looks too close.
    It's hard to tell from the pictures, but the generator will be 4' plus away from the wall and 6' plus away from any windows/doors.


  60. #60
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Bill Chinook View Post
    This may seem like a dumb question, but what are you going to do for hot water? I noticed neither of the two water heaters are powered by the generator.
    My main concern is to ensure that I have heat/cooling and water pressure during an extended power outage event, to prevent damage from freezing or heat. Having hot water is just a luxury I can do without. Also, based on my load calculations, if all the HVACs are running in defrost mode, AND both water heaters were to come on at the same time, the 36KW generator could be overloaded.

    This may also be a dumb question, but why are you bothering with a generator in the first place? Why not just a portable generator for emergencies?
    I travel a lot, leaving the house unattended for weeks at a time, so I need to have a fully automated backup system to ensure no damage occur during an extended outage. The diesel generator I picked is also rated for "prime" power, meaning is it designed to run 24/7 for as long as it needs to while utility power is unavailable. With a 125 gallon fuel tank, and a 20% load on average, my estimation is that it will run for about a week non-stop before running out of fuel. The odds that I'm away during such an event is so low that's a risk I'm willing to take.

    Last edited by Peter Clausen; 09-13-2015 at 07:32 AM.

  61. #61
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post


    It's hard to tell from the pictures, but the generator will be 4' plus away from the wall and 6' plus away from any windows/doors.
    That clearance may not be enough .

    All answers based on unamended National Electrical codes.

  62. #62
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    It's hard to tell from the pictures, but the generator will be 4' plus away from the wall and 6' plus away from any windows/doors.
    That may be close to what is required, but it depends ...

    The clearance for internal combustion exhaust is, as I recall, at least 5 feet from an opening into the house ... however, many whole house generators have their exhaust discharge within the housing of the generator and into the air stream of the air cooling for the motor, which makes that air no longer "internal combustion exhaust" (I don't recall the exact terminology used) as the exhaust is combined and diluted with the fresh air used for cooling - and is thus the exhaust of the cooling air/internal combustion exhaust is not subject to those clearances (went through this years ago in South Florida in the mid-to-late 1990s when generators started being installed after Hurricane Andrew (1992).

    How is your generator configured? Is the internal combustion exhaust diluted into the cooling air?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  63. #63
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    Default Re: Adding 36KW generator to one of two 200A panels

    Quote Originally Posted by Peter Clausen View Post
    With a 125 gallon fuel tank, and a 20% load on average, my estimation is that it will run for about a week non-stop before running out of fuel.
    You did your calculations from fuel usage stated for the generator, I presume - but 125 gallons for a week?

    As a comparison, I has a 16 kW propane generator and two 120 gallon propane tanks (holding 100 gallons of propane each), I calculated that the 200 gallons of propane should last about 4 days with 25% average load (as I recall, I used 25%) - after Hurricane Wilma power was off for 4 days, the fuel gauges read well below the bottom reading of 10% fuel for each tank. I figure I may have had a combined 10 gallons left in the tanks ... which may have lasted another 4 hours at most - then we would have been out of power like everyone else - us and the 4 neighbors I had cords going to so they had their refrigerator, microwave, and a couple of lights - each cord was plugged into a 20 amp receptacle on different circuits I had coming off the generator (maybe they were 15 amp circuits, don't recall for sure as that was 10 years ago).

    Just seems like 125 gallons would not last a week with you running the ACs (we had the water heater on so everyone could take hot showers but not the AC).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  64. #64
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    Default Re: Adding 36KW generator to one of two 200A panels

    Just got a chance to read this thread. Where are the electricians on this site......

    1. That Generac pad mounted generator is not an SDS and thus the neutral is not bonded in the device.

    2. A 400 amp rated disconnect switch needs to be installed in front of the transfer switch and both panels located in the house. Since the house panels are now sub panels no neutral/ground bond in either panel.

    3. Now the neutral ground bond is made in the disconnect switch and only there. No bonding in transfer switch and no switching the neutral in there either.

    4. Despite whether the POCO allows it, that bare copper wire in the meter pan is a parallel neutral. The NEC does not like parallel neutrals.

    Recommend as others have that the OP hire a qualified electrician.


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