Possible Undersized Main Service Breaker

[Joe Arcaro]

Hi:

It appears that this 100-amp breaker is mismatched in size with an aluminum service wire.

Can anyone tell if this wire is tinned copper?
If this wire is tinned copper, is it sized correctly?

Thanks,
Joe

[John Kogel]

Hi:

It appears that this 100-amp breaker is mismatched in size with an aluminum service wire.

Can anyone tell if this wire is tinned copper?
If this wire is tinned copper, is it sized correctly?

Thanks,
JoeThe service conductors may be tinned copper, because the insulation is likely rubber under the cloth. Can't tell the gauge. That whole panel install is poorly done, with a large knockout missing on the right, missing cable clamp, amateur workmanship. Along with that flaky feeder to the water heater, there's work for an electrician there.

[John Steinke]

I'm not sure I understand your question.

That is ... so what if the wires are larger than you expect? As long as they fit in the breaker lugs, there's no problem. To carry it to an extreme, you could have 500MCM wires feeding a 15-amp breaker.

Or, are you asking are the wires too small? Well, if this is the main disconnect, then the wires are under the exclusive control of the utility, and thus the NEC does not apply - read the introduction (Article 90) - regardless of whatever other tables and references you might find in the NEC. The PoCo sizes wires / services by their own standards.

[James Duffin]

? Well, if this is the main disconnect, then the wires are under the exclusive control of the utility, and thus the NEC does not apply - read the introduction (Article 90) - regardless of whatever other tables and references you might find in the NEC. The PoCo sizes wires / services by their own standards.

It is my understanding that the power company stop at the top of the meter and from the bottom of the meter forward falls under the NEC....at least in the areas I work in.

[John Steinke]

Really? Then how would you work on these wires without breaking the utility's seal? What amperage would you assign the feed? How would you applytap rules?