Thread: Improper breaker size?

I was wondering what some of you fine folk would say about this one.


Overhead service to the house.
2/0 AL SEC from the overhead connection into the meter box with 150 amp breaker at the exterior, then 2/0 AL from the meter box to the panel in the basement.

Panel in the basement is a new 200 amp panel with a 200 amp breaker disconnect - again, with the 2/0 aluminum feeding the panel.

OK? Not OK? Somewhere in between?

The electrician has declared it fine since the 150 amp breaker is present as the main shut-off.

Thanks for you input.

Similar Threads:

• ridge vent size
• Psychedelic FP breaker
• Double wired breaker
• Improper flahing method?
• From the old board, Circuit Breaker Short Circuit Fault Rating

The electrician is right.

The 200 amp breaker in the basement panel is not even required.

As long as the service equipment main disconnect is the proper size - and it is at 150 amps - then anything after that which is higher rated is still not going to be able to draw more than will get through that 150 amp breaker until that breaker trips.

It is a nice safety feature, in my opinion, to have a 'panel main' for every panel, and as the main disconnect is 150 amps the appropriate 'panel main' would be 150 amp too, but the main purpose of the 'panel main' is not overcurrent protection but the ability to disconnect the panel with one action - so the 'panel main' could be an unfused molded case switch and the same level of safety would be reached.

IMO it is a good deal that they installed a 200 amp panel with a 200 amp main breaker. This will give them some growing room in the future if they elect to up size to a 200 amp service. My only complaint would be if I had 200 amp service to the home by the utility I would have preferred that they would have gone ahead and sized my service entrance conductors to 200 amps and also my service disconnect. The meter should already be a 200cl.

Maybe somewhat off the OP question but, is there a requirement for the feed from the main disconnect to the panel to be 4 wire?

Originally Posted by Gary Bottomley

Maybe somewhat off the OP question but, is there a requirement for the feed from the main disconnect to the panel to be 4 wire?

Yes...

Originally Posted by Gary Bottomley

Maybe somewhat off the OP question but, is there a requirement for the feed from the main disconnect to the panel to be 4 wire?

Yes Gary, the service disconnect would be outside where the neutral and ground were bonded. Anything downstream, in the same building, would require a 4 wire feed.

Here is a different setup. The main is a knife switch fed by 4/0 Alum (200 Amp) from the weatherhead. Due to the health of the occupant (who was home at the time) I could not shut the power off to look inside this box. It appears that the main is tapped to feed two distribution panels (noted on each side of this knife switch) with 4/0 copper. Both side distribution panels have 150 Amp main breakers. There are also 2 remote distribution panels that are fed off of one of the main distribution panels (each containing a 100 amp main breaker). The first tap to the garage and then on to an out building. I referred it to a licensed electrician for evaluation and repair (might take him a while).

Originally Posted by Tom King

I was wondering what some of you fine folk would say about this one.


Overhead service to the house.
2/0 AL SEC from the overhead connection into the meter box with 150 amp breaker at the exterior, then 2/0 AL from the meter box to the panel in the basement.

Panel in the basement is a new 200 amp panel with a 200 amp breaker disconnect - again, with the 2/0 aluminum feeding the panel.

OK? Not OK? Somewhere in between?

The electrician has declared it fine since the 150 amp breaker is present as the main shut-off.

Thanks for you input.

Electrician is correct.. the 150 Amp exterior main is protecting the 2/0 AL. The 200 Amp disconnect downstream serves no real purpose other than an interior switch.

Originally Posted by Gary Bottomley

Maybe somewhat off the OP question but, is there a requirement for the feed from the main disconnect to the panel to be 4 wire?

Yes.

The neutral is only allowed to be bonded to ground at the service equipment.

The only way to do that is to run a separate neutral and ground the rest of the way, from the service equipment on.

Remember, though, if the system is conduit, the conduit is allowed to be used as the grounding conductor, in which case you would appear to only have 3 conductors H-H-N, but the conduit would actually make it H-H-N-G.

Originally Posted by Jerry Peck

Yes.

The neutral is only allowed to be bonded to ground at the service equipment.

The only way to do that is to run a separate neutral and ground the rest of the way, from the service equipment on.

Remember, though, if the system is conduit, the conduit is allowed to be used as the grounding conductor, in which case you would appear to only have 3 conductors H-H-N, but the conduit would actually make it H-H-N-G.

Thanks Jerry, good explanation.
to follow up, it seems like I run into this a fair amount with older homes that don't comply with this set-up, only having the H-H-N. Is this a relatively new code provision and even though I don't usually attempt to play the game of did it meet code at the time of construction but simply comment that it doesn't meet the current code and safety practice, do you know roughly when this provision was adopted and what is the main purpose and or added safety feature for this requirement in new construction?

Gary,

Typically, the reason you find that so often on older homes is that the inside panel was the service equipment at the time of construction, and the service entrance conductors (service entrance cable or otherwise) only contained H-H-N and the neutral was the ground to the service equipment).

Decades later, new service equipment is installed on the exterior and the inside panel is no longer the service equipment, but the cost to replace those conductors (which are now feeder conductors) is a prohibiting factor, so the electrician just leaves those conductors and uses them as feeders and the H-H-N with the neural grounded is used to replace the H-H-N-G and now the neutral current is running on all the grounded enclosure, equipment, everything metal which is grounded and is fed from that inside panel.

Later, and sometimes at the same time the new service is installed, that inside panel is replaced with a larger panel, yet the feeder conductors are still not replaced.

This results in the service equipment outside, the old service entrance conductors being used used as feeders to the new 200 amp panel inside, and that new panel is not properly grounded and the neutral at the new panel is bonded to ground at the new panel and all along the conductors back to the service equipment.

This lead to current being measured in all sorts of wrong places as the neutral current is finding every ground path back to the new service equipment, as well as through the neutral too.

Think of a car with the battery grounded and the taillight has one hot lead and ground - the current for that lamp goes through the entire car body and frame to get back to the battery, now multiply that current by all the lamps, now multiply that by everything operating in the house which creates unbalances neutral current and that unbalance neutral current is going through the house to get back to 'the battery' (the service equipment).

So, how does an inspector comment on this situation?

Originally Posted by Gary Bottomley

So, how does an inspector comment on this situation?

An inspector reports on what he sees (or doesn't see) as is required by his state SOP if they exist.

In this case, the inspector doesn't see the required neutral and ground separation in the panel. This can lead to dangerous currents being present on the grounding conductor. The remedy is to have a licensed and competent electrician perform the necessary repairs.

Originally Posted by Corn Walker

An inspector reports on what he sees (or doesn't see) as is required by his state SOP if they exist.

In this case, the inspector doesn't see the required neutral and ground separation in the panel. This can lead to dangerous currents being present on the grounding conductor. The remedy is to have a licensed and competent electrician perform the necessary repairs.

Thanks Corn & Jerry also;
Good information.

Originally Posted by Gary Bottomley

So, how does an inspector comment on this situation?

Originally Posted by Corn Walker

An inspector reports on what he sees (or doesn't see) as is required by his state SOP if they exist.

In this case, the inspector doesn't see the required neutral and ground separation in the panel. This can lead to dangerous currents being present on the grounding conductor. The remedy is to have a licensed and competent electrician perform the necessary repairs.

I would come right out and state that a licensed and competent electrical contractor needs to replace the feeder conductors from the service equipment to the panel (i.e., "replace feeder conductors" instead of "perform necessary repairs").

By saying to perform necessary repairs, the electrical contractor may not deem that "necessary" at the cost of replacement, and you are not off the hook because you did not say that they needed to be replaced.

Just come right out and say what needs to be done, if the electrical contractor says otherwise, stick to your guns and if the client gives in, the work is not done, there is a fire, shock or electrocution - YOU said to REPLACE them.

Jerry I'm surprised. U did not inform the readers that there are exceptions to grounding or earthing or bonding the service neutral conductor downstream of the service disconnect (or main).

Previous we know, in past code cycles, is the exception regarding separate structures (dare I say remote...). But alas, there are others.

Originally Posted by Jerry Peck

Yes.

The neutral is only allowed to be bonded to ground at the service equipment.

The only way to do that is to run a separate neutral and ground the rest of the way, from the service equipment on.

Remember, though, if the system is conduit, the conduit is allowed to be used as the grounding conductor, in which case you would appear to only have 3 conductors H-H-N, but the conduit would actually make it H-H-N-G.

Jerry:
So does the set up in the attached photo of the job I inspected this morning meet this requirement as the two service panels are connected to the service equipment enclosure by the conduit, thus creating the -G- for the panels?
(Sorry, I didn't feel comfortable taking the cover off the 400amp enclosure.)

Originally Posted by Gary Bottomley

Jerry:
So does the set up in the attached photo of the job I inspected this morning meet this requirement as the two service panels are connected to the service equipment enclosure by the conduit, thus creating the -G- for the panels?
(Sorry, I didn't feel comfortable taking the cover off the 400amp enclosure.)

Assuming the enclosure in the middle (or some other enclosure not pictured) is the service disconnect, it's wrong. In each of the panels to the left and right of that enclosure the neutral bus bar should be electrically isolated from the enclosure whereas the grounding bus bar should be electrically bonded to the enclosure. All neutral conductors should land on the neutral bus bar and all grounding conductors should land on the ground bus bar. That doesn't appear to be the case in the photo you've provided.

Originally Posted by Corn Walker

Assuming the enclosure in the middle (or some other enclosure not pictured) is the service disconnect, it's wrong. In each of the panels to the left and right of that enclosure the neutral bus bar should be electrically isolated from the enclosure whereas the grounding bus bar should be electrically bonded to the enclosure. All neutral conductors should land on the neutral bus bar and all grounding conductors should land on the ground bus bar. That doesn't appear to be the case in the photo you've provided.

OK, the enclosure in the middle does house a 400amp disconnect and at this point I can only assume the wiring inside is correct except there is only 3 wire feeds to each panel (4/0 alum, 3wire H-H-N) to 200amp panel disconnect breakers.
So does this appear to be a relatively easy fix? Maybe just run a ground wire between the service disconnect and side (not sub but whats the proper term?) panels along with separating ground and neutral wires at the bus bars?
Also, do you think this installation was up to code when it was installed in 1980?

Originally Posted by Gary Bottomley

OK, the enclosure in the middle does house a 400amp disconnect and at this point I can only assume the wiring inside is correct except there is only 3 wire feeds to each panel (4/0 alum, 3wire H-H-N) to 200amp panel disconnect breakers.
So does this appear to be a relatively easy fix? Maybe just run a ground wire between the service disconnect and side (not sub but whats the proper term?) panels along with separating ground and neutral wires at the bus bars?
Also, do you think this installation was up to code when it was installed in 1980?

4/0 AL would be too small since the panel does not carry the entire load of the dwelling. It does not meet the criteria of 310.15(B)6.

Originally Posted by Gary Bottomley

Jerry:
So does the set up in the attached photo of the job I inspected this morning meet this requirement as the two service panels are connected to the service equipment enclosure by the conduit, thus creating the -G- for the panels?
(Sorry, I didn't feel comfortable taking the cover off the 400amp enclosure.)

In my opinion that would be a set of three grouped service disconnects and would be fine.

Originally Posted by Gary Bottomley

So does this appear to be a relatively easy fix?

There is no need to fix anything there. IMO.
Edit :There is a repair needed. The neutral buses need to be isolated from ground in the right and left panelboards, see Roger's post #35.

The conduit provides adequate grounding, as long as the electrician installed the correct nuts. I see a bare grounding conductor entering the central panel.
The 4/0 conductors are protected by the 200amp breakers. As James says, grouped service panels.

Originally Posted by bob smit

Jerry I'm surprised. U did not inform the readers that there are exceptions to grounding or earthing or bonding the service neutral conductor downstream of the service disconnect (or main).

Previous we know, in past code cycles, is the exception regarding separate structures (dare I say remote...). But alas, there are others.

Bob,

I did not mention that ("regarding separate structures") as we were not talking about a separate structure and that exception (now gone by the wayside) possibly would only have confused and complicated the discussion.

Originally Posted by Gary Bottomley

OK, the enclosure in the middle does house a 400amp disconnect and at this point I can only assume the wiring inside is correct except there is only 3 wire feeds to each panel (4/0 alum, 3wire H-H-N) to 200amp panel disconnect breakers.
So does this appear to be a relatively easy fix? Maybe just run a ground wire between the service disconnect and side (not sub but whats the proper term?) panels along with separating ground and neutral wires at the bus bars?
Also, do you think this installation was up to code when it was installed in 1980?

Gary,

First, as Rollie said:

Originally Posted by Rollie Meyers

4/0 AL would be too small since the panel does not carry the entire load of the dwelling. It does not meet the criteria of 310.15(B)6.

That means that the 4/0 aluminum feeder conductor would need to be replaced with 300 kcmil if the main disconnect was old and was only rated for 60 degree C, however, if the main disconnect was rated for 75 degree C, then 4/0 would still be allowed as the next larger standard rating above its 75 degree C rating of 180 amp is 200 amps (standard ampere ratings are -underline and bold are mine-: "The standard ampere ratings for fuses and inverse time circuit breakers shall be considered 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes.").

IF things were done as John says:

Originally Posted by John Kogel

The conduit provides adequate grounding, as long as the electrician installed the correct nuts.

But it does not look like things were done that way, bonding bushings were not installed, however, it is possible that bonding bushings were not required at the time of installation of that equipment due to the apparent age of that equipment.

If bonding bushings were installed, then, yes, the metal conduit could serve as the equipment grounding conductor from the service disconnect to the right and left panels.

That is presuming the basics of what is being discussed, there is information we do not know, such as are those metal conduit in concentric knockouts?

I see a bare grounding conductor entering the central panel.

Actually, I suspect that is 'leaving' the center panel as that is likely the grounding electrode conductor going to the grounding electrode system.

The 4/0 conductors are protected by the 200amp breakers.

And that MAY ... or MAY NOT ... be okay - see above information on conductor size and rating.

Originally Posted by John Kogel

There is no need to fix anything there. IMO.
People are blurting out responses here so now you have mine.
The conduit provides adequate grounding, as long as the electrician installed the correct nuts. I see a bare grounding conductor entering the central panel.
The 4/0 conductors are protected by the 200amp breakers. As James says, grouped service panels.

Ok Where do you see this invisable bare wire i thought i had good eyes got out my magnifying glass and my superman cape and couldnt find it anywhere

Originally Posted by Mark S. Connely

Ok Where do you see this invisable bare wire i thought i had good eyes got out my magnifying glass and my superman cape and couldnt find it anywhere

See photo in post #18, bottom right of center main disconnect panel.

Originally Posted by Jerry Peck

See photo in post #18, bottom right of center main disconnect panel.

Nope! Jerry Peck, look again ! That is a tan-insulated individual copper conductor.

Gary B, there is an eclectic mix of multiple modifications to the system over many years; many of which are unsafe and improper wiring methods and have always been; some modifications in combination with others - it is the combination which presents safety issues.

The unprotected penetrations of the masonry wall, improper wiring methods entering and exiting the "pool pump timer" can, exposed individual conductors, wiring method to the right, above and below the cabinet/panel on the right, is this obvious occupied storage zone, etc.

The telephone transformer plugged into the receptacle should have been removed decades ago as well.

You are right to refer.

Originally Posted by H.G. Watson, Sr.

Nope! Jerry Peck, look again ! That is a tan-insulated individual copper conductor.

Are you sure, H. G.?
- Gary, is that a bare copper or a tan insulated conductor?

Originally Posted by Jerry Peck

Are you sure, H. G.?
- Gary, is that a bare copper or a tan insulated conductor?

see attached blow up i think that is a telephone wire it is certainly too small and flexible for a ground

Originally Posted by Mark S. Connely

see attached blow up i think that is a telephone wire it is certainly too small and flexible for a ground

Mark & Jerry:
If you blow-up the lower left portion of this attached photo, the vertical line is a bare copper wire and it appears the horizontal wire is actually 2 wires of unknown purpose.
Hope that helps.
I know there are other issues but, I was just asking about the 3 vs 4 wire connection from the main disconnect to the two service panels and so far it seems that the jury is still out on that!

I don't see why having a extra main should be a problem since the panels are grouped. If someone wanted to press the issue the easiest fix would be to make the center panel into a junction box with no main and that would be plain silly..

Originally Posted by Gary Bottomley

I know there are other issues but, I was just asking about the 3 vs 4 wire connection from the main disconnect to the two service panels and so far it seems that the jury is still out on that!

Ignore whatever I wrote below. I was sleep deprived and riding a bus and couldn't load the images when I wrote it.

It depends. If the enclosures are bonded together then that can be considered a grouped service and the fourth grounding wire is not necessary. If the enclosures are not bonded together then they need correction by either bonding the enclosures together to create a grouped service or adding a fourth grounding conductor and separating grounds and neutrals.

Originally Posted by Gary Bottomley

Mark & Jerry:
If you blow-up the lower left portion of this attached photo, the vertical line is a bare copper wire ...

Thank you Gary.

I was just asking about the 3 vs 4 wire connection from the main disconnect to the two service panels and so far it seems that the jury is still out on that!

4 "conductors" are required, H-H-H-G, keep in mind, though, that the metallic offset nipple connecting the center panel to the right panel (as shown in your most recent photo) is likely the intended "4th" (ground) "conductor".

Originally Posted by Corn Walker

It depends. If the enclosures are bonded together then that can be considered a grouped service and the fourth grounding wire is not necessary. If the enclosures are not bonded together then they need correction by either bonding the enclosures together to create a grouped service or adding a fourth grounding conductor and separating grounds and neutrals.

You cannot bond the service equipment with the two remote panels shown without separating neutral and ground in those remote panels. If you do not neutral current will be returning to the source over the metal conduit bonding the remote panels to the service equipment enclosure.

I'm confused what you mean by a 'grouped service' if you bond the three panels together ??

The main breakers in the two remote panels are not grouped by bonding the panels. You have one means for a single throw to disconnect all power to the dwelling and that is the service equipment in the center panel enclosure. There is no difference between bonding the panels with metal conduit nipples or offsets or running a egc between panels both means 'bond' the metal of the panels to the service neutral at the service equipment.

What you have here is a 400 amp service with two runs of feeders to two 200 amp remote panels and should have a class 320 meter base outside.

Originally Posted by Roger Frazee

I'm confused what you mean by a 'grouped service' if you bond the three panels together ??

I wrote that reply on a bus and the images weren't loading so I was going from (obviously faulty) memory. Someone mentioned it was a "grouped service" in which case the service should be able to be disconnected with six throws of the hand or less. Looking at the picture now, that doesn't seem to be the case.

You're correct, in that picture there appears to be a service disconnect ahead of the two panels which means the other enclosures are remote panels and not part of the service disconnect.

Originally Posted by Corn Walker

I wrote that reply on a bus and the images weren't loading so I was going from (obviously faulty) memory. Someone mentioned it was a "grouped service" in which case the service should be able to be disconnected with six throws of the hand or less. Looking at the picture now, that doesn't seem to be the case.

You're correct, in that picture there appears to be a service disconnect ahead of the two panels which means the other enclosures are remote panels and not part of the service disconnect.

I hate to ride on a bus. Anyway I have been a victum of lack of sleep and pictures not loading. It happens and you are not at your best in those cases. Hope your bus was on time ... .

Originally Posted by Roger Frazee

You cannot bond the service equipment with the two remote panels shown without separating neutral and ground in those remote panels. If you do not neutral current will be returning to the source over the metal conduit bonding the remote panels to the service equipment enclosure.

Thanks Roger. I've corrected my old post. There is repair work to do after all.

Originally Posted by Roger Frazee

I hate to ride on a bus. Anyway I have been a victum of lack of sleep and pictures not loading. It happens and you are not at your best in those cases. Hope your bus was on time ... .

No sleep, bus driver was a lunatic, and traffic made the bus late but the ferries were running late as well. Sunny skies, sandy beaches, and I've just removed the last bit of K&T from my in-laws' vacation home so I can't complain.

Funny, looking back I should have remembered that I originally suggested the grounds and neutrals needed to be isolated, so I later contradicted my own reply. Sheesh! Maybe that's why my wife just got me "Moonwalking with Einstein" which is apparently a book about improving your memory.

Originally Posted by Corn Walker

No sleep, bus driver was a lunatic, and traffic made the bus late but the ferries were running late as well. Sunny skies, sandy beaches, and I've just removed the last bit of K&T from my in-laws' vacation home so I can't complain.

Funny, looking back I should have remembered that I originally suggested the grounds and neutrals needed to be isolated, so I later contradicted my own reply. Sheesh! Maybe that's why my wife just got me "Moonwalking with Einstein" which is apparently a book about improving your memory.

Well if it helps my memory I better be buying that book too ... Have a good evening Corn ... same to you John

Originally Posted by Roger Frazee

Well if it helps my memory I better be buying that book too ...

What book?