transformers

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talala

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I have a 3 phase, 480v pri, 120/208 sec. transformer that is fed by a distribution breaker 500 feet away. sec is protected by a brkr in same room. do I need to provide a disconnect at the unit since the distribution brkr is so far away?
 
Re: transformers

Per the NEC - NO

But remember the NEC is a minimum requirement and not a design manual.
 
Re: transformers

[Moderator?s Note: Reply has been moved ? it had been inadvertently posted as a new topic.]
Originally posted by talala:
Mr. dungar, I'm not doubting for one minute your response. Also, this is my first time using this site. I'd like to expand on this x-former app. just a little. pri brkr is 500' away, sec brkr in same room, which feeds 3 seperate buildings 200', 300', and 500' from this new distribution. still nothing on being able to disconnect primary power at the transformer?
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Re: transformers

That is a different situation. You may need disconnects at each building. What type of buildings? Commercial, industrial, or school, etc? And where does the utilities wiring end?

Steve
 
Re: transformers

As Steve has said, you've changed the situation.

Transformers do not require the primary disconnect to be near nor within sight of the transformer. In fact the required disconnect does not even have to be lockable in the open position.

Feeders to separate buildings usually need to be treated as service entrances, including the disconnect and grounding requirements.

You need to describe your layout in more detail. I am not sure if the transformer is feeding the buildings (primary disconnect not needed) or is located in each building (disconnect required for building).
 
Re: transformers

Careful, some state/local codes do require pri disconnects. I think Oregon or WA state is one of them... I can't remember and don't have them handy.
 
Re: transformers

In my practice , I always use disconnects before and the load being so far away this transformer should either feed a breaker panel or another disconnect. I think safety is the main issue here . Imagine running 500' if Murphy's visits you :)
 
Re: transformers

It's not required, but for "good practice" I would provide one. If you have to do work on the unit, you have to go 500 feet to turn off the power. :)
 
Re: transformers

Originally posted by don_resqcapt19:
Lady,
Although, I think this is up to the AHJ
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How is this up to the AHJ? He can't require something that the code does not require.
Don
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You might think so, but a lot of times you can argue up and down, and they will make it a point to what they say goes, especially if you want your CO.

Believe me.....it's happened to my friend and I while working in the field several times. :(
 
Re: transformers

Lady,
Just because some inspectors abuse their authority, doesn't make it right. The person and the governmental authority that he represents can be sued for this type of activity. Would you permit a police officer to give you a speeding ticket for going 50 mph when the speed limit is 55 mph? An inspector enforcing something that is not in the code or local amendments is the same thing.
Don
 
Re: transformers

Originally posted by don_resqcapt19:
Lady,
Just because some inspectors abuse their authority, doesn't make it right. The person and the governmental authority that he represents can be sued for this type of activity. Would you permit a police officer to give you a speeding ticket for going 50 mph when the speed limit is 55 mph? An inspector enforcing something that is not in the code or local amendments is the same thing.
Don
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I agree Don, but it does happen. By the time you get into litgation or delay of project, you might as well put in a 500 dollar unit or something, and that's my point. Especially if the client wants the CO.

You're right...they are wrong, but a lot have abused their authority in that way. It's sad... :)
 
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