Dual Voltage Rated Breaker

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Little Bill

Staff member
Tennessee NEC:2017
Semi-Retired Electrician
What would happen should you use a straight 240V rated breaker where a dual or slash rated 120/240V breaker is existing?

Maybe someone here can tell me this. I have a customer with a main breaker that is going bad. It is a GE 225A 120/240V breaker. The number on the breaker is TQD21225.
When trying to find a replacement I keep getting told that number is no good and I should get a TQD22225.
From what I can find out, the "22225" is a straight 240V breaker and not a dual rated 120/240V.
Does anyone know if this is true? If so, what happens if the straight rated breaker is used? Will the 120V loads be protected?

Any GE guys here that can help me on this?


Senior Member
You can use a straight 240V rated breaker in a 120/240 panel, what you cannot do is use a slash rated 120/240 breaker in a high leg 240/120D panel, where B phase is 208V to ground.

I always ask what the line to ground voltage is as it relate to the voltage rating of the breaker. It must be rated to clear a phase to ground fault. When you see a rating of 120/240v as you so aptly pointed out the breaker has a rating of 120v L-G which isn't going to cut it with a delta system where you may have 208 or 240v to ground.
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