Multiple 1-phase circuits on 3-phase breaker

[kjjack]

I have a code question. What are the related NEC code rules associated with wiring multiple single phase circuits to a single 3-phase breaker?

I have five 10 amp single phase loads I want to feed from a single 30A three phase breaker.

 

[jghrist]

I don't think there are any code restrictions, but if you do this, you will lose all of your 1Ø loads when the breaker trips. Why not use single pole breakers? The conductor must be rated for 30A.

 

[DMagyar]

kjjack, check 240.6; 240.20(B) and the exhibits 240.4 through 240.6 listed in the 2009 NEC. It seems that your proposed solution is permitted but isn't commonly applied in that fashion. The most common application is to use individual single pole C/B'S as was mentioned by "jghrist". Further the mention of handle ties is for the similtaineous disconnecting of the associated loads, not common trip.

 

[resqcapt19]

I believe that there is only one breaker manufacturer that has handle ties for 3 single pole breakers so you may see more use of 3 pole breakers on a multiwire branch circuits to comply with the rule in 210.4(B) in the 2008 NEC.

 

[waross]

It's a nice feature for maintenance to trip all three circuits when single phase circuits share a common neutral.
The case may be argued either way.

Bill
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"Why not the best?"
Jimmy Carter