boost xfmr wire size

[Smart $]

I am fairly certain the OP is talking about the factory installed leads on the buck boost transformers.

Ah! That makes sense.

NEC does not have direct purview on the leads as they are part of an assembly that is UL listed. They probably have high-temp rated insulation and, as Ingenieur mentioned, a much higher ampacity rating than the common building wire the NEC deals with.

 

[Ingenieur]

Table 310-19 http://www.champcable.com/pdf/Allowable_Conductor_Ampacity.pdf

#12 as high as 78 A
#10 over 100 A

 

[philhanna@comcast.net]

I am fairly certain the OP is talking about the factory installed leads on the buck boost transformers.

That is correct. They are 1.5 kva transfomers with approriate leads for isolation transformer duty, but we are using them for boosting the voltage from 208v to 222v for a total 36kva motor load.

 

[philhanna@comcast.net]

Ah! That makes sense.

NEC does not have direct purview on the leads as they are part of an assembly that is UL listed. They probably have high-temp rated insulation and, as Ingenieur mentioned, a much higher ampacity rating than the common building wire the NEC deals with.

That makes sense. Thank you.

 

[philhanna@comcast.net]

Table 310-19 http://www.champcable.com/pdf/Allowable_Conductor_Ampacity.pdf

#12 as high as 78 A
#10 over 100 A

Thanks for the table. That makes sense. Thank you.

 

[iwire]

That is correct. They are 1.5 kva transfomers with approriate leads for isolation transformer duty, but we are using them for boosting the voltage from 208v to 222v for a total 36kva motor load.

It is fine and normal, I install many of these.

 

[philhanna@comcast.net]

It is fine and normal, I install many of these.

Thanks. I appreciate it.

 

[philhanna@comcast.net]

Table 310-19 http://www.champcable.com/pdf/Allowable_Conductor_Ampacity.pdf

#12 as high as 78 A
#10 over 100 A

Thank you