150Amp??

[HalfordElectric]

There are 6 or 7 rules for parallel conductors and I have seen all of them broken. I think there are a few things that save the circuit. First, everything is over-engineered by about 200%, second, everything is under utilized by 50%, and third, the smaller or shorter conductor heats more, which increases its resistance and transfers some of the load to the larger or longer conductor. That isn't to say that other opinions expressed here are not just as valid.

Breakers react to heat and heat is averaged. This is the reason a motor can start on a breaker. So, as long as the average heat is below the heat allowed for the breaker, everything is okay.

As to the issue of voltage drop, I'm feel compelled to support Mr. Hansen.

Its a 150 amp service, regardless of the size or length of the internal wiring. That belongs to a higher authority. If the external wiring doesn't meet code, its a defect.

Oh, and hi, everyone.