15kV Switchgear Creepage and Clearances

[Wirenut]

When designing medium voltage switchgear (15kV), do any standards exsist in regard to minim creepage and clearance distances. Should these distances be a factor of envirionmental conditions, scheduled maintenance, etc. Does any one have any references on this subject.

Wirenut

 

[paddy]

There are various standards you need to consult. It first depends on your market. I suspect at 15 kV it is in Europe, however the standards you need to consult are EN Standards which catalog this well. In the American market you need to consider Canadian Standards (CSA) and NEC Standards which have greater clearances than EN but at differing voltage levels.Are you looking at indoor or outdoor? Then you will have to consider environmental factors which are also covered in most standards in terms of severity. Near the sea you will have maximum values as an example.
One other source of problems are the bushings and stand-offs, which have differing ratings than 15 kV. 12 kV is a standard and I believe the next one is >20kV.
Hope this helps.

 

[Wirenut]

Your answer does help. As I suspect, and you seem to agree that these distances can't just be looked up in a table. There are many factors to be considered. I can only say that there are no specific standards for this rather unique application. Wirenut

 

[busbar]

One listing is 99NEC Table 490-24. Minimum Clearance of Live Parts. I thought someone else referenced an ANSI C37 standard here, but I can’t seem to find it. There’s a couple of applicable BILs and indoor vs. outdoor locations.

 

[jbartos]

Suggestions:
1. Contact UL standards or visit

http://www.ul.com/seminars/prodaudio.htm

2. IEC Standards

http://www.iecee.org/ctl/decisions.htm

http://www.iecee.org/ctl/sheet/sheet260.PDF

3.

http://www.phihongusa.com/html/spacing.html

4. Search military specifications at

http://astimage.daps.dla.mil/quicksearch

for mil specs and standards