Multiwire Circuit & Tandem Breakers

Old 04-20-03, 12:52 PM
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Multiwire Circuit & Tandem Breakers

I am planning to add several tandem breakers to my Square D 125 amp panel. The panel takes up to 12 tandem breakers. I read on this forum that using a multiwire circuit on the same tandem breaker is prohibited. My question is can I connect a multiwire circuit to two different tandem breakers?

Here is what I have in mind. Right now I have the disposal and the dishwasher on a multiwire circuit connected to two separate single pole breakers. What I am planning to do is add another multiwire circuit for the fridge and microwave, and then connect these four circuits to two tandem breakers, the dishwasher & fridge on one, the disposal & microwave on another. By doing this the individual circuits in a multiwire circuit would not share the same tandem breaker and instead be on different tandem breakers. Would that work?

Thanks in advance.
Old 04-20-03, 01:56 PM
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Yes, you can do what you describe. You must be very certain that the two tandem breakers are on opposite legs of the power. The easiest way to do this is to make sure that twe two tandem breakers are one above the other. A better choice would be to buy a quad breaker, since this will ensure that the legs are opposite, and would give a common trip lever for the two outside breakers, and the two inside breakers.
Old 04-20-03, 06:15 PM
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If either of the two multiwire circuits will serve a common recept yolk, or two hots on a recept (one for the top and one for the bottom with the tab broken-out), then there must be a handle tie to force both single pole breakers to act as a double pole breaker.
Old 04-21-03, 03:09 PM
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According to Square D's website, there are no quad breakers for my panel (QO type).

The handle ties, are they to tie all four handles on the two tandem breakers or to tie the two handles on each breaker.

Thanks again.
Old 04-21-03, 11:00 PM
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What is a "multiwire circuit"?
I intend to replace 2 single pole 20 amp breakers with 2 20-amp tandem breakers (1 new 20 amp circuit for a freezer and 3 new receptles; 1 new 20 amp circuit for a sump pump) and 1 single pole 15-amp breaker with a 15 amp tandem breaker (for additional lighting). Any information about tandem breakers would be appreciated. Thanks.
Old 04-22-03, 06:36 AM
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A multiwire circuit is 2 circuits that use a common neutral . You have only 3 wires instead of 4 for 2 circuits. It is critical that the hots be on different legs when installing a multiwire circuit.

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