Required Clearance of Live Parts to Grounded Surface inside a NEMA Box

[Skorp1on]

We have vendor supplying a NEMA 4 box for Surge Arrestor/Capictor application and our customer stated that the sidewall clerance is small and may not meet required CSA or IEEE code from live parts to grounded surface. Could you let me know if there is such a requiremetn out there? Especially for clearance inside an electrical cubicle? If there is not requirement, please specific section (s) of CSA and/or IEEE stating this.

connection is to be made to the busbar inside the enclosure. Line voltage is 6.6-6.9 kV.

I understand there is special requirement of exposed live parts relative to building structure/etc.

Anyone help/insight would be greatly appreciated.

 

[pwrengrds]

I am not sure of the CSA requirments but the NEC has a table showing minimium clearance of bare live parts. It can be found in NEC table 490.24. For 7.2kV indoors the clearance is 5.5 inches phase to phase, and 4 inches phase to ground.

 

[Skorp1on]

Thanks pwrengrds - that was helpful. Now to see whether CSA has a similar table. It seems that CSA might be written based on NEC sometimes.