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  1. #1
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    Default generator wiring with switch

    I'm trying to understand how the neutral in the emergency service panel can ever be separate from the main panel even if you have a transfer switch. In addition, must you seperate the neutrals and grounds in the emergency panel? How are they then grounded, when using the generator?

    Crawl Space Creeper

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    Default Re: generator wiring with switch

    I believe you are referring to (proper term) "optional standby systems".

    The preferred wiring method is to not switch the neutral conductor.

    If the neutral conductor is switched, the generator becomes a "separately derived system at which time you need to ... go to that section of NEC and do things that way.

    The simpler way is to leave the neutral connected.

    Jerry Peck
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    Default Re: generator wiring with switch

    Depending on the occupancy, a switched neutral may be required. So you need to be careful.

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: generator wiring with switch

    Quote Originally Posted by Roland Miller View Post
    Depending on the occupancy, a switched neutral may be required. So you need to be careful.
    I suspect he is referring to a house, none the less, is a switched neutral ever required for an optional standby system?

    I don't recall it is, but I could be completely wrong on that.

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    Default Re: generator wiring with switch

    is a switched neutral ever required for an optional standby system? NO

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: generator wiring with switch

    Quote Originally Posted by Roland Miller View Post
    is a switched neutral ever required for an optional standby system? NO
    I guess what needs to be clarified is the terminology being used as the NEC addresses these systems as:
    - Emergency Systems
    - Legally Required Standby Systems
    - Optional Standby Systems

    Most homes which have generators have Portable Generators while some homes have permanent mounted 'whole house' type generators. These generators are Optional Standby Systems.

    Most people refer to Optional Standby Systems as "emergency generators", which is what I suspect is the case here.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by patrice conklin View Post
    I'm trying to understand how the neutral in the emergency service panel can ever be separate from the main panel even if you have a transfer switch. In addition, must you seperate the neutrals and grounds in the emergency panel? How are they then grounded, when using the generator?
    YOu keep ground and neutral separate even in an emergency panel. Also keep in mind that the generator neutral must not be bonded to the generator case or generator ground wire since a residential ATS does not switch the neutral.

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    Default Re: generator wiring with switch

    Please define what a floating neutral is with regard to portable generators?

    I ask as I have a tractor powered (pto) generator and in the literature it refers to a floating neutral.

    Thanks,


  9. #9
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    Default Re: generator wiring with switch

    Quote Originally Posted by Raymond Wand View Post
    Please define what a floating neutral is with regard to portable generators?

    I ask as I have a tractor powered (pto) generator and in the literature it refers to a floating neutral.

    Thanks,
    A floating neutral is a neutral such from a generator or transformer that is not connected to the ground buss or frame. These are usually designed around a residential set up where the generator will feed a service that already has a neutral to ground bond (this being the main bonding jumper).


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    Default Re: generator wiring with switch

    Thank you. Mr. Brooke


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    Default Re: generator wiring with switch

    Quote Originally Posted by Raymond Wand View Post
    Thank you. Mr. Brooke
    If you are talking about a whole house standby generator, the transfer switch becomes the main and what was the main panel becomes a sub-panel which necessitates the separation of the neutrals and the grounds. Since this is not a separately derived system--the neutral is not switched, the generator will not have its own ground but is grounded through the house system.


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    Default Re: generator wiring with switch

    Thank you Dan.


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    Default Re: generator wiring with switch

    Quote Originally Posted by Dan Kramer View Post
    If you are talking about a whole house standby generator, the transfer switch becomes the main and what was the main panel becomes a sub-panel which necessitates the separation of the neutrals and the grounds.
    So ... the "main panel" is also the "service equipment panel where the neutral is REQUIRED to be bonded to ground ... are you going to install the generator to use that as the "main panel" for the circuits powered by the generator?

    I hope not.

    Just another reason to use the terms "service equipment" for the panel which is also the service equipment, and to use "remote panel", "downstream panel", etc., to designate that the panel is *not* the service equipment panel.

    That is also why most "whole house generators" (i.e., "optional standby power system") come with their own "emergency panel" with the circuits which are to be powered by the generator. The transfer switch (usually automatic with these generators) transfers the power from the service equipment where the neutral is bonded to ground, to the "emergency panel" where the generator becomes the "service equipment" where the neutral is bonded to ground and the "emergency panel" becomes the remote panel where the neutral is isolated from ground. No need to figure out how to disconnect the neutral from ground or what happens when you do.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    So ... the "main panel" is also the "service equipment panel where the neutral is REQUIRED to be bonded to ground ... are you going to install the generator to use that as the "main panel" for the circuits powered by the generator?

    I hope not.

    Just another reason to use the terms "service equipment" for the panel which is also the service equipment, and to use "remote panel", "downstream panel", etc., to designate that the panel is *not* the service equipment panel.

    That is also why most "whole house generators" (i.e., "optional standby power system") come with their own "emergency panel" with the circuits which are to be powered by the generator. The transfer switch (usually automatic with these generators) transfers the power from the service equipment where the neutral is bonded to ground, to the "emergency panel" where the generator becomes the "service equipment" where the neutral is bonded to ground and the "emergency panel" becomes the remote panel where the neutral is isolated from ground. No need to figure out how to disconnect the neutral from ground or what happens when you do.
    Jerry-

    Read Dan's reply carefully.

    He is talking about installing a transfer switch between the existing service equipment panel and the meter. By doing so the new transfer switch ( which must be service rated) is now the service equipment. The Neutral gets bonded at this location as well as all grounding electrode conductors shall also be terminated in this new service switch.
    The "old" service equipment panel is now downstream from the new service switch thus it is now a sub panel. Being a sub panel the neutrals shall be isolated from the grounds.

    This is very common on my side of the world. The set up you describe is not the norm here. It may the norm in your part of the world.


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    Default Re: generator wiring with switch

    Quote Originally Posted by jack davenport View Post
    Jerry-

    Read Dan's reply carefully.

    He is talking about installing a transfer switch between the existing service equipment panel and the meter.

    Jack,

    Read my reply carefully.

    You will see that I said
    - So ... the "main panel" is also the "service equipment panel where the neutral is REQUIRED to be bonded to ground ... are you going to install the generator to use that as the "main panel" for the circuits powered by the generator?

    There are many areas of the country where the service equipment/service disconnect/"main panel" are one and the same.

    Thus, in those many areas of the country, how is he going to address the neutral being bonded to ground at the service equipment/"main panel" when that is the only panel in the house?

    One cannot simply place the transfer switch between the service equipment and the "main panel" when they are one and the same.

    Again, that is why many maybe even most, whole house generators come with their own separate "emergency panel" - because that avoids the problem of not being able to do what he said to do.

    And, when you buy and install a whole house generator you need to wire it up exactly as described in its installation instructions, or else you will need to make sure that all wiring touched meets the NEC. If you wire it exactly as provided for with the provided materials and panel, all of that is part of the generators UL listing and labeling - the wiring may 'look wrong' and may look like 'that can't meet code', but it is and does because it is part of the listing and labeling.


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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    Jack,

    Read my reply carefully.

    You will see that I said
    - So ... the "main panel" is also the "service equipment panel where the neutral is REQUIRED to be bonded to ground ... are you going to install the generator to use that as the "main panel" for the circuits powered by the generator?

    There are many areas of the country where the service equipment/service disconnect/"main panel" are one and the same.

    Thus, in those many areas of the country, how is he going to address the neutral being bonded to ground at the service equipment/"main panel" when that is the only panel in the house?

    One cannot simply place the transfer switch between the service equipment and the "main panel" when they are one and the same.

    Again, that is why many maybe even most, whole house generators come with their own separate "emergency panel" - because that avoids the problem of not being able to do what he said to do.

    And, when you buy and install a whole house generator you need to wire it up exactly as described in its installation instructions, or else you will need to make sure that all wiring touched meets the NEC. If you wire it exactly as provided for with the provided materials and panel, all of that is part of the generators UL listing and labeling - the wiring may 'look wrong' and may look like 'that can't meet code', but it is and does because it is part of the listing and labeling.
    Ok let me get this straight:
    For example purposes only let's say I have a dwelling with a 200 ampere service. This service consists of the meter outside , one (1) 200 amp service rated panel with a 200 ampere main breaker inside. The grounding electrodes go to this panel, the neutral is bonded in this panel. Pretty straight forward basic electric service.
    Now I purchase a generator ( large enough to carry to full load of the dwelling) and I have the option of using one of those factory made up subpanels and only have a limited number of circuits on the generator OR using a service rated transfer switch to transfer the entire 200 ampere service.
    I choose to utilize the 200 ampere service rated transfer switch( which contains a 200 over-current device). I then install this after the meter and ahead of the panel. I bond the neutral in this new switch, take the grounding electrode conductors ( ground rod,footer, cold water ) out of the panel, extend them using irreversible crimps and land them in the transfer switch. Thus the new transfer switch is now the new service equipment as it is the first disconnecting means, it is service rated, it contains a 200 ampere over current device ( as it is service rated). I then isolate the neutrals in the panel thus making it a sub panel.
    Your saying that this is illegal and can not be done ??


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    Default Re: generator wiring with switch

    Quote Originally Posted by jack davenport View Post
    Ok let me get this straight:
    For example purposes only let's say I have a dwelling with a 200 ampere service. This service consists of the meter outside , one (1) 200 amp service rated panel with a 200 ampere main breaker inside. The grounding electrodes go to this panel, the neutral is bonded in this panel. Pretty straight forward basic electric service.
    For clarity:
    a) The 200 amp service equipment panel contains one (1) 200 amp main breaker inside it ... period. There is a remote panel with the breakers for the house in it.
    b) Or are you implying that the 200 amp service panel is also the panel with all the breakers in it too?

    BIG difference between the two: a) or b)?

    The above information is needed before asking your question.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    For clarity:
    a) The 200 amp service equipment panel contains one (1) 200 amp main breaker inside it ... period. There is a remote panel with the breakers for the house in it.
    b) Or are you implying that the 200 amp service panel is also the panel with all the breakers in it too?

    BIG difference between the two: a) or b)?

    The above information is needed before asking your question.
    Like I said 1 200 ampere service rated panel. Its a basic 200 ampere main breaker 40 circuit panel.
    Lets say it has the main breaker and 22 circuit breakers in it.

    AND would it matter if it was just a service rated enclosed breaker or service rated fusible disconnect instead of a panel? ( NO)

    Last edited by jack davenport; 02-10-2014 at 06:10 PM.

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    Default Re: generator wiring with switch

    Quote Originally Posted by jack davenport View Post
    Like I said 1 200 ampere service rated panel. Its a basic 200 ampere main breaker 40 circuit panel.
    Lets say it has the main breaker and 22 circuit breakers in it.
    I will guide you to your answer, but first ...

    AND would it matter if it was just a service rated enclosed breaker or service rated fusible disconnect instead of a panel? ( NO)
    Correct, does not matter if the main service disconnect is an enclosed breaker or a set of fuses in a pull out (or other configuration for the fuses).

    Okay, you buy the whole house generator which comes with a automatic transfer switch and, say, 12 circuit emergency panel.

    HOW are you going to connect it to the existing service equipment panel such that the neutral is isolated from ground ... without switching the neutral?

    I's kinda dense at times and youse got some 'splainin' to do to help me get undense 'bout the above.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    I will guide you to your answer, but first ...



    Correct, does not matter if the main service disconnect is an enclosed breaker or a set of fuses in a pull out (or other configuration for the fuses).

    Okay, you buy the whole house generator which comes with a automatic transfer switch and, say, 12 circuit emergency panel.

    HOW are you going to connect it to the existing service equipment panel such that the neutral is isolated from ground ... without switching the neutral?

    I's kinda dense at times and youse got some 'splainin' to do to help me get undense 'bout the above.
    Where did I say I was using a 12 circuit emergency subpanel ??
    I clearly said I was not using any sub panel. I said I was choosing to use a 200 ampere service rated transfer switch to transfer the entire load. Thus putting it between the meter and panel. Like this:

    :
    Solid neutral , bonded to ground in transfer switch. Thus it is the service equipment and you make the interior panel a sub panel


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    Default Re: generator wiring with switch

    Quote Originally Posted by jack davenport View Post
    Where did I say I was using a 12 circuit emergency subpanel ??
    These were the two options you stated: (bold and underlining are mine)
    Now I purchase a generator ( large enough to carry to full load of the dwelling) and I have the option of using one of those factory made up subpanels and only have a limited number of circuits on the generator OR using a service rated transfer switch to transfer the entire 200 ampere service.


    I clarified the "only have a limited number of circuits" factory panels you mentioned - there is where the 12 circuits came in.

    What you describe can ONLY be done if the existing service equipment is rated as "Suitable for use as service equipment", NOT if it is rated as "Suitable for use as service equipment ONLY" - BOTH types are out there.

    You did not state which you were referring to, just like you did not clarify (until I asked) whether or not the service equipment also contained the panel with the branch circuits in it. I could have asked for additional clarification on what you were thinking but I did not. You could have provided the full information but you did not. *I* should have followed with additional clarification questions, instead I made some presumptions.

    As I said, I am dense at times ... SOMETIMES it is caused by what is on my end (lack of brain power) ... SOMETIMES it is not caused by what is on my end, it is the information (or lack thereof) which is provided or NOT provided, leaving me to try to 'paint the rest of the picture' myself. This time I completed the picture and painted a nice tree, but that was not what you had in your mind.

    IF your existing service equipment was rated for use as service equipment, yes, you are allowed to do what you described.

    IF your existing service equipment was rated for use as service equipment only, no, you are not allowed to do what you described.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    These were the two options you stated: (bold and underlining are mine)
    [/COLOR]

    I clarified the "only have a limited number of circuits" factory panels you mentioned - there is where the 12 circuits came in. NO -- I said I had the OPTION of using a sub panel OR USING A 200 AMP TRANSFER SWITCH. I slao said I chose to use a 200 ampere transfer switch.

    What you describe can ONLY be done if the existing service equipment is rated as "Suitable for use as service equipment", NOT if it is rated as "Suitable for use as service equipment ONLY" - BOTH types are out there. ​I also stated it was service rated - NOT service rated ONLY. One would be pretty hard pressed to find a service rated only switch.

    You did not state which you were referring to, just like you did not clarify (until I asked) whether or not the service equipment also contained the panel with the branch circuits in it Makes no difference if it contained the branch circuits or was just an enclosed breaker.
    I could have asked for additional clarification on what you were thinking but I did not. You could have provided the full information but you did not. *I* should have followed with additional clarification questions, instead I made some presumptions. You know what they say about assuming ........

    As I said, I am dense at times ... SOMETIMES it is caused by what is on my end (lack of brain power) ... SOMETIMES it is not caused by what is on my end, it is the information (or lack thereof) which is provided or NOT provided, leaving me to try to 'paint the rest of the picture' myself. This time I completed the picture and painted a nice tree, but that was not what you had in your mind Some times the light comes on and you realize Oops he's right. So you use your talent of twisting

    IF your existing service equipment was rated for use as service equipment, yes, you are allowed to do what you described Gee this is what I've been saying the entire time

    IF your existing service equipment was rated for use as service equipment only, no, you are not allowed to do what you described.
    Now as a side note - I did enjoy sparring with you

    Oh this is what Dan's reply was all about to begin with



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    Default Re: generator wiring with switch

    "also stated it was service rated - NOT service rated ONLY."

    BOTH types are "service rated".

    "One would be pretty hard pressed to find a service rated only switch."

    Maybe where you are, not where I have been.


    "Makes no difference if it contained the branch circuits or was just an enclosed breaker."

    There you go again, this time I am not falling for it: if it contained an enclosed breaker main disconnect ONLY ... verses if it contained an enclosed breaker main disconnect WITH spaces for branch circuits ... big difference between them - paint the full picture ...

    "Some times the light comes on and you realize Oops he's right. So you use your talent of twisting "

    If only I were that smart - I was typing out a reply to say you can't do what you showed in the drawing ... then stopped ... that is when I realized what I was thinking of versus what you were thinking of - had to delete all of my typing and go back and type it all over again once it hit me that you were thinking of "Suitable for use as service equipment" and not what I was thinking of "Suitable for use as service equipment ONLY" - that is why I asked "how", because I was waiting for you to tell me "how" you isolated the neutral from ground in a panel where the neutral was made bonded to ground.

    "Now as a side note - I did enjoy sparring with you"

    Same here, the more it happens the more I have to think, and now I have to make sure that I ask about what I am thinking and if that is what the other person is thinking - no sense in debating the finer points of something unless all are first talking about the same something. If I am looking at an orange and trying to explain that, no, *it is orange*, but you are looking at an apple and you are trying to explain that, no, *it is red* - until we realize the difference in what we are talking about there can be no agreement in the debate.

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    Default Re: generator wiring with switch

    Jack,

    I figured I would let you get a good night's sleep with that smilely before going ...

    ... Oh ... ... didn't think of those.


    You stated "also stated it was service rated - NOT service rated ONLY."

    I responded "BOTH types are "service rated""

    You also stated "One would be pretty hard pressed to find a service rated only switch."

    To which I responded "Maybe where you are, not where I have been."

    Okay, so now I will state the problem, and if I leave out any details you can ask for clarification:

    I have a 200 amp service, this consists of the meter outside, one (1) 200 amp rated panel with a 200 amp rated main breaker, the grounding electrode conductor goes to this panel and the neutral is bonded in this panel, inside is a 200 amp rated panel.

    Pretty straightforward electric service.

    "Now I purchase a generator ( large enough to carry to full load of the dwelling) and I have the option of using one of those factory made up subpanels and only have a limited number of circuits on the generator OR using a service rated transfer switch to transfer the entire 200 ampere service."

    "HOW are you going to connect it to the existing service equipment panel such that the neutral is isolated from ground ... without switching the neutral?"

    And that installation is a problem all around the country, not just where I am.

    .

    .

    .

    .

    .

    Oh, I guess I may as well add a clarification - one in which it seems you never see because you said "One would be pretty hard pressed to find a service rated only switch." - CLARIFICATION: the meter and service equipment are a bit closer than the meter and service equipment in your drawing, in fact, they are in the same enclosure.

    .

    There are other clarifications which may be needed to see the entire picture, but I think you now understand what I was thinking of.


    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    Jack,

    I figured I would let you get a good night's sleep with that smilely before going ...

    ... Oh ... ... didn't think of those.


    You stated "also stated it was service rated - NOT service rated ONLY."

    I responded "BOTH types are "service rated""

    You also stated "One would be pretty hard pressed to find a service rated only switch."

    To which I responded "Maybe where you are, not where I have been."

    Okay, so now I will state the problem, and if I leave out any details you can ask for clarification:

    I have a 200 amp service, this consists of the meter outside, one (1) 200 amp rated panel with a 200 amp rated main breaker, the grounding electrode conductor goes to this panel and the neutral is bonded in this panel, inside is a 200 amp rated panel.

    Pretty straightforward electric service.

    "Now I purchase a generator ( large enough to carry to full load of the dwelling) and I have the option of using one of those factory made up subpanels and only have a limited number of circuits on the generator OR using a service rated transfer switch to transfer the entire 200 ampere service."

    "HOW are you going to connect it to the existing service equipment panel such that the neutral is isolated from ground ... without switching the neutral?"

    And that installation is a problem all around the country, not just where I am.

    .

    .

    .

    .

    .

    Oh, I guess I may as well add a clarification - one in which it seems you never see because you said "One would be pretty hard pressed to find a service rated only switch." - CLARIFICATION: the meter and service equipment are a bit closer than the meter and service equipment in your drawing, in fact, they are in the same enclosure.

    .

    There are other clarifications which may be needed to see the entire picture, but I think you now understand what I was thinking of.
    Pretty simple --use one of these.

    GenerLink™

    Safely Connect a Portable Generator To Your Home Without Rewiring.

    Homeowners are purchasing portable generators in record numbers to power critical appliances such as furnaces, pumps, refrigerators and home office equipment during a power outage. GenerLink™ is a new product that makes connecting a portable generator easy and safe while providing homeowners the flexibility of using a portable generator to operate virtually any appliance in their home.

    GenerLink™ is a five-inch device that is installed behind your electric meter by your local utility or licensed electrical contractor. When you connect a portable generator to GenerLink™ and start it up, GenerLink™ automatically disconnects your house from the electric utility grid preventing the possibility of back feed, which can damage equipment and harm utility personnel.

    Because GenerLink™ is designed and rated to connect directly to a standard household electric service of 200 amps or less, all you have to do to operate a critical appliance is flip a breaker on in the household breaker panel once the generator is connected and operating. GenerLink™ eliminates the hassles of running multiple extension cordsor hiring an electrician to install an expensive transfer switch and sub-panel that limits the number of appliances you can operate.

    GenerLink™ is installed by your local electric utility in less than 30 minutes. There is no need for you to be home and there is no need to rewire the house.

    Florida Light and Power installs these all over Florida--What's the problem?


    Last edited by Roland Miller; 02-11-2014 at 09:01 AM.
    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: generator wiring with switch

    Roland,

    I guess you missed the part of the discussion regarding the generator being a whole house generator (I.e., permanently mounted/installed and wired in to the house).

    Those are for portable generators which have the required receptacles as those come with a 20 foot cord to connect the generator to the transfer switch.

    Maybe they make those for permanently wiring a whole house generator to? I haven't seen one anywhere yet, but maybe you have? They might be out there and I just haven't seen one yet - not even advertised.

    Jerry Peck
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    Roland,

    I guess you missed the part of the discussion regarding the generator being a whole house generator (I.e., permanently mounted/installed and wired in to the house).

    Those are for portable generators which have the required receptacles as those come with a 20 foot cord to connect the generator to the transfer switch.

    Maybe they make those for permanently wiring a whole house generator to? I haven't seen one anywhere yet, but maybe you have? They might be out there and I just haven't seen one yet - not even advertised.
    I seem to started quite a discussion. In my first posting, I wrote about a whole house generator which Jerry picked up on right away. That is when the transfer switch becomes the service disconnect and the existing service panel become a sub-panel and therefore the neutrals and grounds must be separated--when inspecting this you have to make sure that the bonding screw or the bonding wire that connects the neutral bar to the panel is removed. The second instance is when there is an ATS (Automatic Transfer Switch) that is using the generator to energizing select circuits. In this case as Jack brought up the ATS receives its power through the existing service panel and when the power goes out it switches to the generator so that there is no back feed to the utility lines. You can have a similar situation with a portable generator. The one that can be tricky for Happy Home Maker is the interface which is becoming popular. The interface is a device that will only allow the portable generator to supply power to the house if the service disconnect--the main breaker--is turned off and the typically the 30 amp break is tuned on allowing the generator to fee the panel. The interface is product specific--you can not put a interface for a SqD panel on a GE panel. The problem with this is you have a 6500W generator potentially energizing the whole house. HHM has to be thoroughly instructed to turn off all the breakers and only turn on the few that are needed--heat source, well, fridge, perhaps the microwave and a light or 2. This one of the many reasons why it is most important that the breakers be properly labeled. One last point, make sure that the cord for portable generator is at least 15' long so that the generator can be at least 10' from the house. All of the above is for an optional standby system that is what you find at most homes.

    Last edited by Dan Kramer; 02-11-2014 at 03:02 PM. Reason: When talking about the bonding screw or wire, it hs to be removed

  28. #28
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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post
    Jack,

    I figured I would let you get a good night's sleep with that smilely before going ...

    ... Oh ... ... didn't think of those.


    ask for clarification:

    I have a 200 amp service, this consists of the meter outside, one (1) 200 amp rated panel with a 200 amp rated main breaker, the grounding electrode conductor goes to this panel and the neutral is bonded in this panel, inside is a 200 amp rated panel.

    Pretty straightforward electric service.
    OK now I understand your confusion .

    You are referring to a meter /main combo. Where I was referring to a separate meter and panel.
    No they are not common "on my side of the island".

    am I correct?

    Last edited by jack davenport; 02-11-2014 at 05:58 PM.

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    Default Re: generator wiring with switch

    Quote Originally Posted by Dan Kramer View Post
    That is when the transfer switch becomes the service disconnect and the existing service panel become a sub-panel and therefore the neutrals and grounds must be separated--when inspecting this you have to make sure that the bonding screw or the bonding wire that connects the neutral bar to the panel is removed.
    Dan,

    And that is why I started asking the "how" as in "how" is the neutral isolated from ground when the meter, service equipment, and panel are in one combination enclosure which has the neutral permanently bonded to the enclosure with no way to isolate the neutral from the enclosure.

    Those combination meter/service equipment/panels are common in many of the places I have been.

    That was precisely the question I was going to ask Roland about the transfer switches which are installed at the meter - because that creates a bit of a problem ... even with separate service equipment where the neutral bonding screw can be removed.

    This is why: the generator has a 4-wire connection (permanently wired for a whole house generator, cord and plug with a portable generator) which contains a separate ground, usually insulated, a separate and insulated neutral, and two separate and insulated hot conductors, however, at the transfer switch which goes in behind the meter, the service entrance from the meter to the service equipment is (in many areas) SE cable which is only 3-wire and contains a combination uninsulated neutral/ground and two separate insulated hot conductors.

    Removing the neutral bonding screw does nothing to isolate the neutral from ground.

    The only way to make those transfer switch work would be to replace the service entrance conductors with a 4-wire SER cable (if SE was installed) and that might not be all that easy.

    Just some food for thought.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

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    Default Re: generator wiring with switch

    Quote Originally Posted by jack davenport View Post
    OK now I understand your confusion .

    You are referring to a meter /main combo. Where I was referring to a separate meter and panel.
    No they are not common "on my side of the island".

    am I correct?
    Yes, you are correct, that is what I was referring to.

    And to make matters even more complicated (one of the clarifications I was saving ) is that the combination meter and service equipment also has a panel below the main service disconnects, and that panel supplies the pool panel, the irrigation pump, the two air conditioner condenser units, the separate workshop, all kinds of circuits are supplied from that panel. The inside panel provides the circuits for all the stuff inside the houses. That means one cannot just bypass the outside service equipment and catch the inside panel to catch everything for the house.

    Makes it a bit more complicated than some envision.

    Guess it is based on what we are used to seeing and working with.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

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    Default Re: generator wiring with switch

    "And that is why I started asking the "how" as in "how" is the neutral isolated from ground when the meter, service equipment, and panel are in one combination enclosure which has the neutral permanently bonded to the enclosure with no way to isolate the neutral from the enclosure.

    Those combination meter/service equipment/panels are common in many of the places I have been.

    That was precisely the question I was going to ask Roland about the transfer switches which are installed at the meter - because that creates a bit of a problem ... even with separate service equipment where the neutral bonding screw can be removed.--Jerry"

    Jerry-- there is no requirement to change the grounding and bonding when using a meter base mounted transfer switch because the configuration of the service main has not changed and you can bond anywhere from the "service" disconnect up to the "service" overcurrent device. So leaving the bonding and grounding electrode system in the existing panel is still NEC compliant. And the neutral is an acceptable "required" bond to the meter assembly.


    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: generator wiring with switch

    As an addition--as long as the neutral is not switched (transfered) the generator is not a separately derived system and all the changes at the service panel are not required by code. So I don't know what some of you are up to without a diagram..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

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    Default Re: generator wiring with switch

    Quote Originally Posted by Roland Miller View Post
    Jerry-- there is no requirement to change the grounding and bonding when using a meter base mounted transfer switch because the configuration of the service main has not changed and you can bond anywhere from the "service" disconnect up to the "service" overcurrent device. So leaving the bonding and grounding electrode system in the existing panel is still NEC compliant. And the neutral is an acceptable "required" bond to the meter assembly.

    250.24 Grounding Service-Supplied Alternating-Current Systems.

    - (A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5).
    - - (1) General. The grounding electrode conductor connection shall be made at any accessible point from the load end of the service drop or service lateral to and including the terminal or bus to which the grounded service conductor is connected at the service disconnecting means.
    - - - FPN: See definitions of Service Drop and Service Lateral in Article 100.
    - - (5) Load-Side Grounding Connections. A grounded conductor shall not be connected to normally non–current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article.
    FPN: See 250.30(A) for separately derived systems, 250.32 for connections at separate buildings or structures, and 250.142 for use of the grounded circuit conductor for grounding equipment.


    As you have stated, that behind-the-meter transfer switch is the main disconnecting means and is the point at which the grounded conductor is bonded to the grounding electrode system, and the conductors from that behind-the-meter transfer switch are "on the load side of the service disconnecting means" at which point a grounded conductor "shall not be connected to" ... "equipment grounding conductors" ... "or be reconnected to ground on the load side of the service disconnecting means".

    To me, unless I am missing something, that means the conductors from the "load side of the service disconnecting means" (that transfer switch) are no permitted to be connected to ground. Or am I just having a brain fart and in need of a couple of days off?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

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    Default Re: generator wiring with switch

    Quote Originally Posted by Jerry Peck View Post

    Guess it is based on what we are used to seeing and working with.
    You hit the nail on the head

    The up here the use of meter main combo's are normally those stand alone pedestals for speed cameras, red light cameras, and traffic signals. House use a meter on the exterior with the panels on the interior. Makes life so much simpler.


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