Disconnecting means surge withstand

[mbrooke]

Obviously its not in the NEC, but to what standard are disconnects built to? How far must the contacts separate or is there a specific dielectric requirement between contacts? I can't find anything clear.

 

[Tony S]

If you look in the ABB MCCB catalogue it gives the contact clearance and the various standards.

 

[romex jockey]

How and why is a distinct separation distance specified ?


~RJ~

 

[mbrooke]

If you look in the ABB MCCB catalogue it gives the contact clearance and the various standards.

Thank you, I will take a look at them.

How and why is a distinct separation distance specified ?


~RJ~

Good question, my (though rather feeble) understanding is that it has to do with the line voltage and possible surges. The contacts must be far enough that incoming rated voltage or any inadvertent transients do not arc into the load side contacts.