Code reference for Transformer Disconnect? 1

[Senselessticker]

I have a 480 - 208/120 V inside dry type transformer being fed from an MCC (MCC is located ~100 ft away in different room). I cannot find in the NEC code a reference stating that a disconnect means is required in the room with the transformer. Can anyone provide an NEC reference stating that such a disconnect is required? Many thanks for anyhelp!

 

[Senselessticker]

Sorry guys,

Found the reference 110.58

Thanks

 

[rob46]

Art. 110.58 is applicable to tunnel installations over 600V, which is not your case

 

[alehman]

You can't find it because it does not exist. A primary disconnect is not required to be near the transformer.

 

[rbulsara]

I have run into inspectors requiring local disconncets for LV transformers in Masschusetts. I beleive its somewhere included in Mass Electrical Code.

 

[EEJaime]

alehman is correct, as long as the primary feed is properly protected, the disconnect is not required to be added at the transformer. The one exception is if the transformer feeds directly into a piece of equipment and that piece of equipment is not within 100 feet and in visual site of the MCC, and there is no other disconnecting means between the transformer and the equipment. You would need to have a local disconnect, often it is less expensive to do so with a non-fused switch on the primary side of the transformer.

 

[rbulsara]

110.58 does exist, in 2005 edition of NEC. Its not a change so it must exist in pervious one too. However it is true that it is for systems more than 600V.

What I posted earlier is also a fact. I also agree that it is not required by NEC but some inspectors do.