panel nameplate vs service size

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eplmisme

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bellevue wa
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signal electrical inspector
good afternoon forum,

I work as an electrician for a city. We have services that power our signals and street lighting. It is a split buss panel with the top being fed with a 100amp breaker and the bottom having 4 spot for main breakers. we only install a single pole 30 amp breaker in the lower section to power the intersection controller. The service panel has a name plate that calls the service cabinet a 200amp panel. with the top and bottom breakered per out spec we only have 130 amps. though with the 3 open lower main breaker spaces a greater ampacity could be created.


Does this service need to be fed with 3/0 to facilitate the full 200 amps, or can we re-sticker that the service is only 130amps?
 
Do you know what size/type conductor is supplying the panel ?
 
several are being feed with #2 USE-2 which is rated for exactly 130amps. our new services are being fed with 3/0 USE-2 but i am curious for our own legality for the older panels. and would a phenolic label stating the max ampacity due to wire size be a fix or an admittion of fault
 
The service size is based on the service conductors, they need to be large enough to carry the load. The service panel must be at least the size of the service conductors, it may be larger.
 
i agree with your statement Jim but the question comes up because it is a split buss where half is fed from a single main braker (in this case 100amp) and the lower half is 4 separate main breakers (which we only use one of leaving 3 open spaces for breakers to be added each of which would increase the load of the service) our wire is sized correctly for what we have installed but not for what could be installed.

it isn't a 200 amp panel with a single 100 amp main installed
 
eplmisme said:
several are being feed with #2 USE-2 which is rated for exactly 130amps. our new services are being fed with 3/0 USE-2 but i am curious for our own legality for the older panels. and would a phenolic label stating the max ampacity due to wire size be a fix or an admittion of fault
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130 amps is the 90° C rating. Your conductor at 75° C is actually a 115 amp conductor.
 
IMO, since there is no single main it will be either a 200 amp or ***amp based on the ampacity of the service conductors whichever is less.
 
eplmisme said:
i agree with your statement Jim but the question comes up because it is a split buss where half is fed from a single main braker (in this case 100amp) and the lower half is 4 separate main breakers (which we only use one of leaving 3 open spaces for breakers to be added each of which would increase the load of the service) our wire is sized correctly for what we have installed but not for what could be installed.

it isn't a 200 amp panel with a single 100 amp main installed
Click to expand...
It makes no difference if it is split bus or not. You are only concern with the part of the panel directly fed by the utility. It is not uncommon to find 'main lug' service equipment rated larger than the service size.
The service size is based on what the utility supplies you. Their service conductors are sized differently than NEC conductors.
 
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