AC motor junction box design 1

[thinker]

We are ordering a custom built AC motor which would have
3 axes translation capability. The motor will be supplied
with flying leads which will be terminated with field
wires in separately located junction box. Is there any
limitation on the length of motor flying leads? All we
found so far is NEC article 430-145 (junction box shall be
separated from the motor by not more than 6 ft). Can this
be interpreted as a distance between a motor and a j-box
or this 6 ft length is related to cable length?

 

[gordonl]

I don't use the NEC, but our code has a similar condition and it is a spacing requirement as well as wire minimum. It is spacing so that the ambient from the motor doesn't affect the cabling. I don't see any reason for a maximum length, only the minimum, because this wire would have a higher temperature rating than the incoming field wires, which is required within the 6' radius. Outside the 6' range the higher temperature wire isn't required, but it would be better than the field wire. (Assuming the same size)

 

[thinker]

Thank you, gordonl.Please let me know what is "your" code
you mentioned. Our application requires leads longer than 6'
but we need to prove that this is not a violation.

 

[gordonl]

I am in Ontario Canada, so we use the Ontario Electrical Safety Code which is based on the Canadian Electrical Code. It is often similar to the NEC, but not the same.