200A GE panel - max size breaker allowed

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dana1028

Senior Member
Looking at a 200A GE TM2020 MUF [residential] elect. service main/combo panel.

A label inside says the maximum 'branch breaker' permitted is 90A. Do you think this language also applies to 'feeder breakers'?

We're installing a subpanel and it's a lot easier getting a 100A breaker than getting a 90A - cheaper also. Have a 100A sub with #2 NM already installed, just a matter of buying the breaker for the service panel.
 

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Little Bill

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That's what I'm trying to determine. I'm installing a feeder, not a branch. So...does this label apply to a feeder?

There's no difference between a "feeder" & "branch" as far as the bus bar stabs is concerned.
I'm afraid you're stuck with the 90A if you go by the panel label.

However, I usually see at least a 100A max size for the bus stabs. I have seen some C/H panels that allow 150A.
 

jim dungar

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Wisconsin
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PE (Retired) - Power Systems
It is possible that the maximum wire size for the 100A breaker exceeds the available wire bending space.
UL Listing is performed with the largest possible conductor size the lugs are rated for.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
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I believe wire bending space is what set the maximum breaker size in may of these combination service entrance devices. That is why they list a smaller breaker for AL wire. I have always disagreed with this since I think the manufacture should just list the maximum wire size and let the installer decide on the breaker size.

My suppliers charge me the same price for 280's, 290's and 2100's. They alwasy stock more 100's. In this case I would no loose much sleep over using a 100. You have 95 amp wire so the calculated load must be less than 95 amps. I don't think 5 amps is going to cause a total meltdown.

Siemens/Murray CSED's have a maximum breaker size listed at 70 amps except in the lowest position which can be 100 amps. I see them all the time with 100 amp breakers but have yet to see one with the breaker installed in the correct position.
 

dana1028

Senior Member
I was thinking it was more of an issue of what the bussing could handle (load amperage) on the limit in size of the breaker vs. the amount of wire bending space?

That was my thinking also - if that is the case then that would be a reason to limit a 'branch' vs. a feeder. A branch is more likely to have such a load, but a feeder would be more diversified between multiple loads and not as likely pull as much as a 90 branch.
 

dana1028

Senior Member
There's no difference between a "feeder" & "branch" as far as the bus bar stabs is concerned.
I'm afraid you're stuck with the 90A if you go by the panel label.

However, I usually see at least a 100A max size for the bus stabs. I have seen some C/H panels that allow 150A.

90's not a problem - my load will be an oven and an elect dryer, so 90 is plenty.

Thanx for all the comments, especially the wire bending thought.
 

Dennis Alwon

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Doesn't matter what the load is because the equipment states max. overcurrent protective device. Just get a 90 amp breaker and be done with it. Around here a 90 amp breaker is a stock item
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Years ago one of the manufactures told me the wire bending space is what limited the breaker size to less that the 125A. If the circuit breaker limit is strictly based on the amount of current on the buss stabs why would the the maximum breaker be different for CU vs AL wire?

In the case of this panel the maximum conductor allowed for the space provided is probably #2. Based on the 60C column that would work out for a 90 amp breaker using CU and a 70 amp breaker using AL.

Edited to add last sentence.
 
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shortcircuit2

Senior Member
Location
South of Bawstin
Good point Curt. What about upsized feeder conductor installation for voltage drop though? The panel manufacturer didn't consider this when specifying on that label. I thought that I have seen loadcenters where larger breakers had to be in a specific location on the bussing also. Interesting discussion.
 

jim dungar

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Location
Wisconsin
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PE (Retired) - Power Systems
Good point Curt. What about upsized feeder conductor installation for voltage drop though? The panel manufacturer didn't consider this when specifying on that label. I thought that I have seen loadcenters where larger breakers had to be in a specific location on the bussing also. Interesting discussion.

The breaker would have been limited based on the maximum size conductor that its lugs can handle, not the amount of current flowing through it.

Issues such as specific breaker locations may be due to heat dissipation.
 

templdl

Senior Member
Location
Wisconsin
That was my thinking also - if that is the case then that would be a reason to limit a 'branch' vs. a feeder. A branch is more likely to have such a load, but a feeder would be more diversified between multiple loads and not as likely pull as much as a 90 branch.

Ditto. It most likely is a temperature rise issue when listing the panel.
But again this is an assumtion as would be the wire bending room. Just simply follow what has been included on the NP of the panel to avoid violating the panels UL listing as well as irritating the AHJ.
 
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