Breaker Location Question/Confusion

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Little Bill

Little Bill

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Tennessee NEC:2017
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Semi-Retired Electrician
Let me start with what I have first, then the question:

I changed an outdoor main breaker panel 200A. The panel only has the main 200A breaker and two 100A breakers, each feeding a sub panel. I put the breakers across from each other and that was the way they were installed in the panel I replaced.

This is a small office with just HVAC, receptacles and lights for the load. I would say the building is no more than 500-800 sq ft and 200A is probably overkill anyway.

The confusion I have is this. The inspector called me and said I needed to either drop one of the breakers down, or raise one up. Simply put, not to have them straight across from each other. He said that put too much load on one of the buses and would burn up one side of the bus if it wasn't moved. He said the way it was now it would be too much on one leg/bus.:?

I tried to explain that each 2-pole breaker was using both legs and no matter where I put them they would still be using both legs. It would either be A-B or B-A. Now he didn't check any loads or meter it or anything that I'm aware of.

Am I loosing my mind, because I can't get it in my head what he's talking about?
Also, if the panel is rated for 200A, wouldn't each leg be rated for 200A?

Help an old confused guy out please!:huh:
 
Little Bill said:
Let me start with what I have first, then the question:

I changed an outdoor main breaker panel 200A. The panel only has the main 200A breaker and two 100A breakers, each feeding a sub panel. I put the breakers across from each other and that was the way they were installed in the panel I replaced.

This is a small office with just HVAC, receptacles and lights for the load. I would say the building is no more than 500-800 sq ft and 200A is probably overkill anyway.

The confusion I have is this. The inspector called me and said I needed to either drop one of the breakers down, or raise one up. Simply put, not to have them straight across from each other. He said that put too much load on one of the buses and would burn up one side of the bus if it wasn't moved. He said the way it was now it would be too much on one leg/bus.:?

I tried to explain that each 2-pole breaker was using both legs and no matter where I put them they would still be using both legs. It would either be A-B or B-A. Now he didn't check any loads or meter it or anything that I'm aware of.

Am I loosing my mind, because I can't get it in my head what he's talking about?
Also, if the panel is rated for 200A, wouldn't each leg be rated for 200A?

Help an old confused guy out please!:huh:
Click to expand...

He probably meant too much on one stab...
If you dropped one down 2 spaces or moved one up 2 spaces you would 1/2 the load on those 2 stabs.
Don't know if it's against code but I see his point.

And as Masterinbama pointed out some panels have a max load per stab rating.
 
masterinbama said:
Some panels have a maximum load per stab rating.
Click to expand...

qcroanoke said:
He probably meant too much on one stab...
If you dropped one down 2 spaces or moved one up 2 spaces you would 1/2 the load on those 2 stabs.
Don't know if it's against code but I see his point.

And as Masterinbama pointed out some panels have a max load per stab rating.
Click to expand...

I know some panels limit the the breaker size to 100A for the load side and I think maybe some go up to 150A for the max.

But he didn't say stabs, he said bus, and "that side". Which to me meant leg A or B.
I also could understand if he had checked the loads with an amp meter and found way too much load on either leg.

He didn't fail me but still wanted me to go back and move the breakers. It's about a 50 mile round trip and I really don't want to go if there's no pressing reason to.
With such a small place and small load, I don't see the emergency here. Especially since most panels are listed for 100A per stab.
 
I think the highest rating per stab I have seen listed in panels is 160 Amps. I would have definitely not put 2-100 amp breakers back to back. Do you know the panel model number?
 
masterinbama said:
With your 100 amp breakers opposite each other, you have 200 amps per stab.
Click to expand...

curt swartz said:
I think the highest rating per stab I have seen listed in panels is 160 Amps. I would have definitely not put 2-100 amp breakers back to back. Do you know the panel model number?
Click to expand...

Little Bill said:
C-H BR816B200RF
Click to expand...

I just found the specs on this and according to them each stab is listed for 200A.

CAT.200.01.T.E For more information contact Cutler-Hammer at:
www.ch.cutler-hammer.com/catalog
3-39
January 2001
Loadcenters & Circuit Breakers
3
Type BR
Vol. 1, Ref. No. [0055]
Application Description
Loadcenter Construction
Cutler-Hammer Type BR loadcenters
have standard tin-plated aluminum
bus with a limited availability of cop-
per bus. The sum of the handle ratings
connected to any stab is limited to
150 amperes maximum on the 100

and 125 ampere loadcenters, and
200 amperes on loadcenters with

150 ampere or higher main bus.
NEMA Type 1 boxes or enclosures are
manufactured from galvanized steel.
Raintight boxes are manufactured
from galvanized steel, then finished
using an electrostatic powder coat,
baked urethane paint process.
 
I agree with your interpretation Little Bill. The sum of the handles in this case refer to 100A on the left and 100A on the right for a total of 200.
 
jaylectricity said:
I agree with your interpretation Little Bill. The sum of the handles in this case refer to 100A on the left and 100A on the right for a total of 200.
Click to expand...
It looks like it reads that way, but I initially had a hard time reconciling the apparent approval for putting 200A of (rated not actual) load on one stab when the bus rating is only 150A. I guess that they are assuming that the bus current is still limited by the main breaker or by the feed breaker for an MLO. But if that is true, then the 200A per stab limit for these panels is problematic in combination with the 120% rule allowing PV backfeed when one of these loadcenters is used.

I just found an old but relevant post in another forum which contains a letter from Square D Product Technical Support on exactly this subject. If C-H uses the same language, then it really does mean that you can have a 200A total on a single stab in a BR panel with a 150A or larger bus.

This does make it a little easier to explain why the 120% rule is phrased the way it is.
Some have argued that the maximum current passing a single point on a bus which is fed from opposite ends cannot exceed the greater of the two end feed currents, so the 120% rule is overly conservative. But in fact the entire current sum could end up at a single point on the bus where a fully loaded stab is located. Very interesting!

Anyway, I think that the quote from the C-H spec should get Little Bill off the hook with the inspector.
 
Last edited:
Little Bill said:
I just found the specs on this and according to them each stab is listed for 200A.

CAT.200.01.T.E For more information contact Cutler-Hammer at:
www.ch.cutler-hammer.com/catalog
3-39
January 2001
Loadcenters & Circuit Breakers
3
Type BR
Vol. 1, Ref. No. [0055]
Application Description
Loadcenter Construction
Cutler-Hammer Type BR loadcenters
have standard tin-plated aluminum
bus with a limited availability of cop-
per bus. The sum of the handle ratings
connected to any stab is limited to
150 amperes maximum on the 100

and 125 ampere loadcenters, and
200 amperes on loadcenters with

150 ampere or higher main bus.
NEMA Type 1 boxes or enclosures are
manufactured from galvanized steel.
Raintight boxes are manufactured
from galvanized steel, then finished
using an electrostatic powder coat,
baked urethane paint process.
Click to expand...


Then you are good to go.
 
GoldDigger said:
It looks like it reads that way, but I initially had a hard time reconciling the apparent approval for putting 200A of (rated not actual) load on one stab when the bus rating is only 150A. I guess that they are assuming that the bus current is still limited by the main breaker or by the feed breaker for an MLO. But if that is true, then the 200A per stab limit for these panels is problematic in combination with the 120% rule allowing PV backfeed when one of these loadcenters is used.

I just found an old but relevant post in another forum which contains a letter from Square D Product Technical Support on exactly this subject. If C-H uses the same language, then it really does mean that you can have a 200A total on a single stab in a BR panel with a 150A or larger bus.

This does make it a little easier to explain why the 120% rule is phrased the way it is.
Some have argued that the maximum current passing a single point on a bus which is fed from opposite ends cannot exceed the greater of the two end feed currents, so the 120% rule is overly conservative. But in fact the entire current sum could end up at a single point on the bus where a fully loaded stab is located. Very interesting!

Anyway, I think that the quote from the C-H spec should get Little Bill off the hook with the inspector.
Click to expand...

masterinbama said:
Then you are good to go.
Click to expand...

I just got off the phone with the inspector. I read the spec sheet to him and he said "read that again".
So I read it slowly to him again and he said "looks like you are legal if that's their cut sheet you are reading from".

He thanked me for letting him know that.

One of the more pleasurable conversations I've had with an inspector!:hug:
 
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