Lug separation on a transformer

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heybud

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Hello,
Would you use 374-7 for the spacing of lugs on a transformer. So the minimum spacing between the lugs would be 1" as they are held in free air? Or is there another article that deals with transformers that I haven't found? Thanks for the help. The transformer is 480 to 120/208

Gary
 
Re: Lug separation on a transformer

Gary, I don't think this is covered by the NEC although Wire Bending Space at Terminals is per 373-6(b)and other spaces per370-16(b) via 450-12.

I have put VC material between lugs in transformers in the past for my own piece of mind.

Roger
 
Re: Lug separation on a transformer

Thanks for your time Roger I can't find anything specific either.


Gary
 
Re: Lug separation on a transformer

Guys, transformer lug spacing is part of the manufacturing process. There are some NEMA and IEEE ANSI type standards for manufacturing electrical equipment. Or is your transformer one of the pigtail types that you put lugs on and bolt and tape? If the transformer has a terminal strip tape is not usually needed.
 
Re: Lug separation on a transformer

Gpedens, thanks but that was not the question. Nema and the other standards cover the equipment out the door from the factory, any lugs that may be installed in the field can be extreemly close, even with a lug kit from the manufacturer.

Roger
 
Re: Lug separation on a transformer

right you are Roger...

Too often , I have seen lugs bolted down that have turned or spun too close to other lugs...I even saw one that was caught during yellow lining that was "touching" another lug due to a foreign object hitting the first lug...the foreign object was the panel door !!!!...yikes

anywho, I like to use insulating material on anything that looks like it could be turned within the area of other lugs or conductors or if the voltage is higher than 50 vac.

just my 2 cents worth...
 
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