Spacing between terminations

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Where in the code is the spacing distance between terminals located? I have 15kV terminations in a substation with no insulation or boots. I know there are minimal distances between the terminals themselves and the side or back of the cabinet.

Any replies will be greatly appreciated.
 

Rockyd

Senior Member
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Nevada
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Retired after 40 years as an electrician.
Might be in the NESC rather than NEC -110.34 was pretty vague about any spacing.
 

iceworm

Curmudgeon still using printed IEEE Color Books
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EE (Field - as little design as possible)
Where in the code is the spacing distance between terminals located? I have 15kV terminations in a substation with no insulation or boots. I know there are minimal distances between the terminals themselves and the side or back of the cabinet..
Well, there is 490.24 and T490.24 (2008. But that isn't exactly what you are asking. These cover field fabricated installations. 490.24 specifically does, "... not apply to equipment design, manufactured, and tested in accordance with accepted national standards."

Maybe what you are looking for is in the applicble national standard - ANSI, IEEE, UL, ... Take a look at the equipment nameplate and see if there is a standard listed.

ice
 

jim dungar

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Wisconsin
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PE (Retired) - Power Systems
I have 15kV terminations in a substation with no insulation or boots.
At 15kV uninsulated bus and no boots are probably the most standard construction methods.

I cannot remember the L-G distance but it is around 5" in enclosed equipment.
 

Strife

Senior Member
NEC is not very specific for over 600V, very few references. Because most 600V is handled by POCOS which have their own rules and don't need city inspections. I would check the manufacturer rating but top of my head for 15KV I would say least 4" without boots/insulation

Where in the code is the spacing distance between terminals located? I have 15kV terminations in a substation with no insulation or boots. I know there are minimal distances between the terminals themselves and the side or back of the cabinet.

Any replies will be greatly appreciated.
 

MJJBEE

Member
NESC has the Answer

NESC has the Answer

The answer is 6" in the 2002 NESC (I don't have a current version). The clearances are located in Table 341-1
 
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