Disconnect needed for x-fmer?

[alaskanassassin]

Is a disconnect required for a 480/120/208 transformer located out of site? It is a 30kva transformer fed from a 50 amp circuit breaker. Thanks. Doug

 

[raider1]

Welcome to the forum.

No, a disconnecting means is not required to be installed within sight of a transformer.

You are required to have primary overcurrent protection in accordance with 450.3, but the overcurrent protective device for the primary of the transformer is not required to be within sight of the transformer.

You will need secondary conductor overcurrent protection in accordance with 240.21(C) and this will most likely need to be located either within 10' or 25' of the transformer.

Chris

 

[alaskanassassin]

Thanks for the welcome and fast response. That is what I was thinking and I could not find anything in the code. The secondary has a 100 CB. Thanks again.

 

[raider1]

Your welcome.

Chris

 

[anbm]

It is not required but... it will be a good idea to have another disconnect within sight of transformer primary for maintenance purpose without worry someone accidently turn on xfmr primary breaker at panel.

 

[infinity]

It is not required but... it will be a good idea to have another disconnect within sight of transformer primary for maintenance purpose without worry someone accidently turn on xfmr primary breaker at panel.

That would add a measure of safety but even a disconnect within sight should be locked out and tagged before any work is done on the transformer.