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Posted

I saw a breaker used to supply an AC unit today that appeared to be 4-breakers with an attachment arm. They were labeled 40 20 20 40 This was in a 1972 GE Panel. The four hots wires terminated to this were all 12 gauge. Does this supply proper overcurrent protection? I couldn't trace these wires to the condenser as these were buried in a drop ceiling. The condenser required a 30-AMP service.

Posted
Originally posted by dtontarski

I saw a breaker used to supply an AC unit today that appeared to be 4-breakers with an attachment arm. They were labeled 40 20 20 40 This was in a 1972 GE Panel.

I think you were looking an a half-size double two-pole breaker set. The outer two breakers are linked to each other to serve a 40-amp circuit and the inner two breakers are linked to each other to serve a 20-amp circuit. I presume that the outer circuit fed the AC unit and the inner circuit fed something else.

The four hots wires terminated to this were all 12 gauge. Does this supply proper overcurrent protection?

Strictly speaking, the AC compressor doesn't need the breakers for overcurrent protection; it has its own. The breakers are needed to provide fault protection. To determine whether or not the wires are the correct size, look at the data plate on the AC unit. It'll say something like "minimum supply circuit ampacity" followed by a number. My hunch is that a #12 wire is fine on this one.

I couldn't trace these wires to the condenser as these were buried in a drop ceiling. The condenser required a 30-AMP service.

In the context of electrical wiring, the term "service" refers to the conductors and equipment that deliver electricity from the utility to the building. I'm not sure what you mean by it in this case. Did it say that it required a minimum circuit ampacity of 30 amps or did it say that it required maximum fuse or circuit breaker size of 30 amps? They're two different things on air conditioner compressors.

- Jim Katen, Oregon

Posted

Originally posted by Jim Katen

I think you were looking an a half-size double two-pole breaker set. The outer two breakers are linked to each other to serve a 40-amp circuit and the inner two breakers are linked to each other to serve a 20-amp circuit. I presume that the outer circuit fed the AC unit and the inner circuit fed something else.

From the original description I would agree with Jim. Just FYI, GE never made a breaker like that, so it's someone elses' brand of breaker. I don't think that's a real big deal unless there's some other reason to be concerned, but others disagree.

Brian G.

Fountain of GE Trivia [^]

Posted

The data plate calls for a maximum 30 AMP breaker. The minimum circuit ampacity was less than 20 AMPs.

Thanks for the constructive criticism on my terminology....you've done me a service.

Thanks for identifying this breaker as well. By-the-way, the two inner breakers served the home's dishwasher.

Posted
Originally posted by dtontarski

The data plate calls for a maximum 30 AMP breaker. The minimum circuit ampacity was less than 20 AMPs.

So the 40-amp breaker was too big but the #12 wire was ok, right?

Thanks for the constructive criticism on my terminology....you've done me a service.

Now if you could just explain that to my wife. She doesn't see it your way.

Thanks for identifying this breaker as well. By-the-way, the two inner breakers served the home's dishwasher.

A dishwasher only needs a single pole breaker. The two breakers were probably serving a multi-wire circuit that fed the dishwasher and disposal.

- Jim Katen, Oregon

Posted

The "double quad" breaker works the same way as a double waffer breaker. The thinner profile allows for two separate breakers, thus circuits, in the same space as a full size breaker. The double quad will give two separate 220/240 volt circuits from two busses instead of the four that would be needed with full sized breakers.

It is configured as 20 40 40 20, which is really 20,40-40,20 (inners and outers, as Jim stated)so each leg of each 220/240 circuit is tied into a different buss.

The handle ties, just like the handle ties on a full size double breaker, ensure that both legs of each 220/240 circuit shut down when necessary.

Posted

Jim -

Got it - 40 AMP breaker does not match what the manufacturer calls for. The 12 gauge wire is fine. Further evaluation of panel was called for due to a number of other issues. Thanks again.

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