Main breaker vs. Main Lug

[K_Mark]

When do I need to use a Main Breaker in a sub panel? Where is the code located? This is for an expansion to a YMCA, they are adding a pool.

 

[charlie b]

Re: Main breaker vs. Main Lug

You never need a main breaker, if the sub-panel is in the same building. It's a design choice.

However, if the pool is in a separate building, then the separate building itself would require a disconnecting means. Using a main breaker in the panel would be an easy way to achieve that.

 

[paul32]

Re: Main breaker vs. Main Lug

Never is too strong a word. If the feeder overcurrent device exceeds the rating of the panel it would need a main.

 

[charlie b]

Re: Main breaker vs. Main Lug

That does not constitute a "need." You have the option of reducing the rating on the feeder breaker.

But you are right about the use of the word "never." Change that to,

Well, Hardly Ever!

(With apologies to William Schwenck Gilbert)