200 amp into 100 amp panel

[sdukette]

Hi folks,

I believe I know the correct answer but would appreciate your professional comments. A 200 amp service is run into a 100 amp rated panel and main breaker. The 100 amp breaker is going to limit the amperage going out of the panel, however the panel is only rated for 100amps. Can #4 aluminum fit into a 100 amp breaker? It appeared it must have been drilled out, but I couldn't tell for certain with the anti-oxidant paste present.
The 100 amp panel is full. My recommendation will be to have a qualified electrician evaluate and repair / replace as needed. They should change out the panel to a 200 amp panel citing the panel is not rated for 200amps and possible manipulation to the main lug area. By changing to a 200 amp panel it will be adding capacity to the dwelling if needed in the future.

However the homeowner selling the home may see it as just fine.

 

[Dennis Alwon]

Hi folks,

I believe I know the correct answer but would appreciate your professional comments. A 200 amp service is run into a 100 amp rated panel and main breaker. The 100 amp breaker is going to limit the amperage going out of the panel, however the panel is only rated for 100amps. Can #4 aluminum fit into a 100 amp breaker? It appeared it must have been drilled out, but I couldn't tell for certain with the anti-oxidant paste present.
.

I believe you mean that a 4/0 aluminum is run into a 100 amp main breaker panel. This is legal and it makes the service 100 amp not 200, however the wire will not fit under a 100 amp breaker. You will need to bug on a short piece of wire that would be the appropriate size for 100 amp.

 

[danickstr]

someone may have put the extra fat wire in there to eliminate voltage drop or to make an upgrade later less expensive. it sounds like the only mistake they made was altering the main lug. but oversized wire is usually a good thing, and will save time and hassle if the panel goes to 200 later.

 

[Cavie]

Sounds like you have a 100 amp service. 200 amp meter can does not make it a 200 amp service. I do not think you would have any lug left if you were to drill out 100 amp lugs to accept 4/0 alm wire. #4 alm will fit in 100 amp breaker or lugs just fine. Is there a 200 amp breaker feeding the 100 amp panel?

 

[sdukette]

To cliarifiy,

There is a 200 amp breaker outside at the meter. The #4 cable is run to the 100 amp panel and breaker (subpanel now). I didn't know this side cable would fit into a 100 amp lug. I undrestand it's actually functioning as a 100amp. So as everyone is saying this is to code, even though 200 amps is entering the 100 amp rated panel? The rating must start after the main breaker then... excuse me for my ignorance in this area.
Thanks for helping me understand this more. I appreciate your quick responses.

 

[kbsparky]

IF you have a #4 Aluminum conductor feeding a 100 Amp panel, then you have a violation. #4 Aluminum is only rated for 65 Amps.

You could use a #2 AL conductor and invoke table 310.15(B)(6) for a dwelling unit's 100 Amp service or feeder.

Otherwise, you need at least a #1 AL conductor for a 100 Amp service.


This is all assuming that you have complied with the other provisions of the tap conductor rules which limit your tapped conductor length to 25 feet, in this scenerio.

 

[Dennis Alwon]

To cliarifiy,

There is a 200 amp breaker outside at the meter. The #4 cable is run to the 100 amp panel and breaker (subpanel now). I didn't know this side cable would fit into a 100 amp lug. I undrestand it's actually functioning as a 100amp. So as everyone is saying this is to code, even though 200 amps is entering the 100 amp rated panel? The rating must start after the main breaker then... excuse me for my ignorance in this area.
Thanks for helping me understand this more. I appreciate your quick responses.

What size breaker is the #4 aluminum connected to at the 200 amp panel. If the #4 is connected to a 200 amp breaker then it is a violation if there is a 100 amp breaker on the inside. As stated above the #4 aluminum is not rated for 100 amps

 

[jaylectricity]

It was already clarified that you meant 4/o aluminum and you again posted #4 wire. #4 wire and 4/o wire are completely different sizes.

I suggest you consult an electrician.

 

[Dennis Alwon]

It was already clarified that you meant 4/o aluminum and you again posted #4 wire. #4 wire and 4/o wire are completely different sizes.

I don't believe the OP every used 4/0. I was wondering if that was what he meant when he stated that it woun't fit under the breaker lug.

 

[jaylectricity]

It was already clarified that you meant 4/o aluminum and you again posted #4 wire. #4 wire and 4/o wire are completely different sizes.

I don't believe the OP every used 4/0. I was wondering if that was what he meant when he stated that it woun't fit under the breaker lug.

I understand Dennis, I was saying that somebody else clarified that the OP was talking about 4/0 before the OP came back to clarify their question. Then the OP again used #4 in the statement. If it was #4 wire we wouldn't be having this discussion because a #4 fits nicely in ANY 100 amp breaker...agree?

 

[Dennis Alwon]

I understand Dennis, I was saying that somebody else clarified that the OP was talking about 4/0 before the OP came back to clarify their question. If it was #4 wire we wouldn't be having this discussion...agree?

That is why I asked about the 4/0 and one would think that this is what it is about but.... If there is a 60 amp breaker in the main service that feeds the 100 mb panel then the #4 is leggit. The OP stated

It appeared it must have been drilled out, but I couldn't tell for certain with the anti-oxidant paste present.

To be honest-- I don't know what we have here. OP needs to give us more info.

 

[Cavie]

Sounds like you have a 100 amp service. 200 amp meter can does not make it a 200 amp service. I do not think you would have any lug left if you were to drill out 100 amp lugs to accept 4/0 alm wire. #4 alm will fit in 100 amp breaker or lugs just fine. Is there a 200 amp breaker feeding the 100 amp panel?

My bad. 100 amps is indeed a violation. Wasen't paying attention to the amprerage just thinking about the size of the lugs.