Damaged cable connection at MCB

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petersonra said:
true.

and the recommended bending radius the manufacturers give you is not part of their listing so can effectively be ignored.
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And the installers only assume that the breaker terminations can take the abuse of the torque placed on them by forcing a wire into the terminal from a tight radius or supporting the weight of a wire.
Then the question is does the terminal's purpose of a simple termination of rated wire and using the proper torque to secure it. It could go so far as to break the molding of the breaker damaging it.
 
It is a multifamily with electric heat. The calculated load is roughly 400A based on 220.84.
The amp marking on the circuit breaker is missing.
 
olc said:
It is a multifamily with electric heat. The calculated load is roughly 400A based on 220.84.
The amp marking on the circuit breaker is missing.
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If that's 500MCM cable, it's not rated for 400A in this situation. Repeated overloads may have broken down the insulation. What size is the protective device and do you know if it's functioning?

And yes, it does appear to be a Zinsco main. If it's 400A, you would only be able to load it to 320A max., which would have been OK for the 500MCM cable. But a known issue with Zinsco was that they sometimes failed to trip. So if it was repeatedly loaded to 400A and the breaker never tripped, the cable was overloaded and resulted in the insulation failing over time.
 
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templdl said:
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In addition there is still NEC art 312.6(a) and (B) minimum wire bending radius. ...
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I don't see anything that gives a minimum bending radius...that section just specifies the space that must be available for bending space. There is nothing that says you have to use all of the space. I don't think that there is any minimum bending radius in the NEC for 600 volt and under single conductors.
 
don_resqcapt19 said:
I don't see anything that gives a minimum bending radius...that section just specifies the space that must be available for bending space. There is nothing that says you have to use all of the space. I don't think that there is any minimum bending radius in the NEC for 600 volt and under single conductors.
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Thanks Don, I misspoke.
I should have referenced art312.6 Deflection of conductors (A) width of wiring gutters, (B) wire bending space at terminals and the associated tables.
 
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