A question was raised as to the proper use of a double pole breaker, for a single 120 circuit. In one of our machines a Square D 2 pole 30 amp breaker was installed, with only one leg used for the circuit. I do not know why they did this but they did. Square D literature says the breaker will trip on overload on either leg and mentions that if a 120 volt circuit is used to use the posts by the trip indicator. I am Just wondering if the NEC addresses this anywhere. Seems like this is legal to me.
Double poll breakers
- Thread starter rdimase
- Start date
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- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Double poll breakers
Is this a listed machine? If so then the listing would account for the double pole breakers, if its shown on the drawings then it would be allowed. It may not be a NEC issue at all, as it depends on what the machine is.
Is this a listed machine? If so then the listing would account for the double pole breakers, if its shown on the drawings then it would be allowed. It may not be a NEC issue at all, as it depends on what the machine is.
sparkmantoo
Member
- Location
- Virginia
Re: Double poll breakers
i don,t see anything wrong with it. it is a common trip breaker put in by the manufacturer. i see alot of this where i work but it is from machines built in europe. they use three pole brkrs for single phase feeds. it think it is a cost issue too.
i don,t see anything wrong with it. it is a common trip breaker put in by the manufacturer. i see alot of this where i work but it is from machines built in europe. they use three pole brkrs for single phase feeds. it think it is a cost issue too.
Re: Double poll breakers
If I understand you correctly a 2p common trip breaker was installed but one pole is only being used to feed a 120v load. If so there is no problem. A bit odd as a single pole would normaly be used but 1p of a 2p breaker will work just fine. Maybe they only had a 2p breaker available at the time of the installation.
If I understand you correctly a 2p common trip breaker was installed but one pole is only being used to feed a 120v load. If so there is no problem. A bit odd as a single pole would normaly be used but 1p of a 2p breaker will work just fine. Maybe they only had a 2p breaker available at the time of the installation.
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