transformer ques.

[wireman1]

does a step down transformer 480 volt / 208 /120 three phase need a additional means of disconnecting if the 480 volt breaker is not in sight of the transformer ? or is it ok to just lock it out at the main mc center located at about 100 ft. away

 

[augie47]

I don't have all three of the last Codes at my fingertip, but the requirement has changed from the 2008.As best I recall, a lockable disconnect is sufficient. I do think the locing mechanism has to be permanent.

 

[Smart $]

Either (or both )...

450.14 Disconnecting Means. Transformers, other than Class
2 or Class 3 transformers, shall have a disconnecting means
located either in sight of the transformer or in a remote location.
Where located in a remote location, the disconnecting
means shall be lockable in accordance with 110.25, and its
location shall be field marked on the transformer.

 

[augie47]

Note that the requirement does depend on which Code cycle is being enforced.
The '08 does not have the 450.14 requirement.

 

[Smart $]

Note that the requirement does depend on which Code cycle is being enforced.
The '08 does not have the 450.14 requirement.

450.14 added in 2011. Wording changed for 2014 but essentially still the same.

450.14 Disconnecting Means. Transformers, other than
Class 2 or Class 3 transformers, shall have a disconnecting
means located either in sight of the transformer or in
a remote location. Where located in a remote location,
the disconnecting means shall be lockable, and the location
shall be field marked on the transformer.