(transformer). Readily accessible disconnecting means within sight of equipment.

[victor.cherkashi]

Readily accessible disconnecting means within sight is required for many equipments, but I can't find in NEC requirement for a transformer. It doesn't make sense for me to see 1000 KVA dry transformer in a room which has primary winding switch 400 feet away (in main electrical room).

 

[petersonra]

Readily accessible disconnecting means within sight is required for many equipments, but I can't find in NEC requirement for a transformer. It doesn't make sense for me to see 1000 KVA dry transformer in a room which has primary winding switch 400 feet away (in main electrical room).

how often are you going to need to open the switch? once every decade?

 

[dkidd]

Look at 450.14

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.

 

[victor.cherkashi]

450.14. Good point. I looked into 2008 NEC (NYC uses 2008 NEC), this requirement came in 2011 NEC.

 

[jim dungar]

450.14. Good point. I looked into 2008 NEC (NYC uses 2008 NEC), this requirement came in 2011 NEC.

But the disconnect can be remote if it is lockable, therefore there is no absolute 'within sight' requirement.

 

[iwire]

But the disconnect can be remote if it is lockable, therefore there is no absolute 'within sight' requirement.

It seems we take advantage of that as I have not seen us installing disconnects for transformers yet and we are under the 2014.

 

[iwire]

how often are you going to need to open the switch? once every decade?

Or never.

 

[don_resqcapt19]

It seems we take advantage of that as I have not seen us installing disconnects for transformers yet and we are under the 2014.

In reality almost all transformers have disconnects in the form of their primary OCPD. The only real change in the 2014 code is the label requirement if the disconnect is not local to the transformer.

 

[JJtechguy]

Transformer disconnect

Transformer disconnect

I have noticed people mounting disconnects to the outside of dry type transformers. This appears to be sloppy work in my opinion. Has anyone else seen this done? Is there a code violation? If so please give me a reference.

 

[ActionDave]

I have noticed people mounting disconnects to the outside of dry type transformers. This appears to be sloppy work in my opinion. Has anyone else seen this done? Is there a code violation? If so please give me a reference.

Where are you seeing this and why would anyone do it? What don said is entirely correct so there is no reason for a disconnect, just a label.

 

[infinity]

450.14. Good point. I looked into 2008 NEC (NYC uses 2008 NEC), this requirement came in 2011 NEC.

That's correct, no disconnect within sight or label required.

 

[GoldDigger]

I am guessing they simply wrote the rule for worst case.

You don't have to supply fancy Italian water, just tap water in a container with a spigot is fine.

Wrong thread??

 

[Tony S]

Just a question.
Would a remote MV trip push button be required?

 

[don_resqcapt19]

Just a question.
Would a remote MV trip push button be required?

The NEC does not require that.

 

[iwire]

Wrong thread??

Yes it was, I moved it to the right thread.

Thanks.

 

[Besoeker]

But the disconnect can be remote if it is lockable, therefore there is no absolute 'within sight' requirement.

I'd want it lockable whether within sight or not.
Actually, that would be specified/expected whether mandated or not.