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tandem breaker

11740 Views 11 Replies 8 Participants Last post by  Stubbie
We have a contractor putting in a whirlpool tub that requires 2 15 amp circuits into a GFI plug. The contractor told me to buy a tandem breaker because I only have room for one more breaker. I have a GE box which requires GE breakers. Lowes and Home Depot don't have them but the guy that works there says I can use another brand because it has the same footprint. Is this true?
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The answer is yes there are a few brands that are "GE Compatible". Of course they will have to be UL listed for this use.
How old is your GE panel? Unless it is more than 30 years old .....

the answer is NO, because no one makes the ½-size THQP breakers except GE. There are no UL-Classified replacements for them that I'm aware of.

Most any electrical supplier should have them available.
Rule #1 of DIY
Don't believe what they say at the big box stores
I've run into some very knowledgable people
But most are pretty clueless
The GE panels I have seen require a specific syle of "tandem" breaker. They are actually "thin" breakers...two seperate units.

If he runs a 3 wire cable to supply the two circuits, make sure the "thins" end up on opposite phases.
Slow down everyone, he said he had a GE panel.
There are two common types, either it can take "half size" (1/2") or "full size" (1") breakers. Now I've learned long ago ago not to have too much faith in the Home Depot employees, but if the guy told him he can use another brand, it's probably because he showed him the breaker and it was full size.
In this case he's correct there are a few brands that can be used. For example http://www.grainger.com/Grainger/items/3YMV3.
Thats why I replied to his question "yes he's right". Everyone that is arguing on this seems to be referring to the GE half sized breakers.
...Thats why I replied to his question "yes he's right". Everyone that is arguing on this seems to be referring to the GE half sized breakers.
That's because the half-sized GE breakers are the only breakers approved for a GE panel that will give you two breakers in a full 1" space.
That's because the half-sized GE breakers are the only breakers approved for a GE panel that will give you two breakers in a full 1" space.
Very good, the unit goes into a 1" slot. So its a full size breaker not half size. (if it was half size the would no point, you could just use two half size breakers)
http://www.lowes.com/lowes/lkn?acti...ctId=71985-76863-THQP220&detail=cr&lpage=none
If the OP does indeed get a tandem breaker to fit in the panel, the 2 new 15amp circuits cannot be run through 14/3 (or 12/3) from the panel to the new outlet box. This would be considered a MWBC (Multi-Wire Branch Circuit) and the neutral would have the chance of being overloaded with the two hot sources on the same leg of the panel. Either 2 individual runs of wire need to be made (to 2 separate outlet boxes), or move some circuits around to put the 2 new runs on separate legs of the panel.

You will need 2 outlet boxes or a double gang box for 2 GFCI outlets anyway, as you cannot split a GFCI outlet. The GFCI breakers also tend to get pretty expensive, and with a 2 pole breaker its gets to be even more outrageous.
Very good, the unit goes into a 1" slot. So its a full size breaker not half size. (if it was half size the would no point, you could just use two half size breakers)
http://www.lowes.com/lowes/lkn?acti...ctId=71985-76863-THQP220&detail=cr&lpage=none
Unfortunately that double pole breaker will not work if he only has one space and one buss stab left. It is a THQP 1/2 size double pole and it does not install in a 1" single pole space. It requires you to use 1/2 of two 1" spaces. I would surmise that you are not familiar with these style GE breakers??

He simply needs 2... 1/2 size thqp single pole breakers and two runs of 2 conductor romex.

If his panel is old or does not accept the 1/2 size thql's there may be tandems that will replace a full size (1") single pole thql but they need to be classified as kbsparky mentioned. I'm not sure about the latter.
Vann

I should make a correction to my last post....that breaker will not install in a 1" single pole space and give you two legs of the panel as is required for a double pole 240 volt application. It will install and would give you two single pole circuits. The breakers are tied so if one trips the other will trip also. They are not common trip however. So there is a chance that even though one trips the other may not.

Giving this some thought makes me consider actually using this 1/2 size double pole breaker if both gfci's are going to be in the same box at the whirlpool. I see a bit of an increase in safety over two circuits in the same box protected by individual 1/2" thqp circuit breakers. Both circuits will lose power because of the handle tie and remove all power at the electrical box. So if you open it up for inspection you won't get surprised by a still energized branch circuit. You will still need 2 runs of 14/2G if the circuits are required to be 15 amp.

The question that remains to be answered is does the panel accept 1/2 size thqp's or not some GE panels do and some don't.
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