Tandem vs. Double Pole

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  #1  
Old 03-28-05, 04:03 AM
CyberEddy
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Tandem vs. Double Pole

Can you explain the difference between tandem and double pole circuit breakers and when one is used versus the other? Thanks
 
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  #2  
Old 03-28-05, 05:21 AM
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A tandem breaker is sometimes called a mini breaker. It is really two circuit breakers in a single package, the size of a normal single breaker. They are separate and distinct breakers. In most panels they yield two separate circuits while connecting to a single point on the incoming power plane at the rear of the panel.

A double pole breaker is a 240 volt breaker. It is twice the size of a normal breaker and it is designed to connect to both planes at the rear of the panel, thus providing 240 volts between the two terminals.

This is where it gets confusing. On some panels you can use a tandem breaker as a 240 volt breaker, depending upon where it is positioned in the panel.

Further confusing the issue is that for some panels you can purchase a quad breaker. A quad breaker is two tandem breakers in a package, yielding fur breakers. In this configuration the center two breakers are usually joined to provide a 240 volt breaker, while the outer two each provide 120 volts.
 
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Old 03-28-05, 07:45 AM
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And to be even more confusing, some manufacturers call their tandem breakers "double-pole".

Fundamentally, they are really the same thing. The difference comes in whether or not the two poles must be connected to the same leg of the power or whether they may be connected to opposite legs. Most (but not all) tandem breakers can only connect to one leg of the power. To get 240 volts, you need to connect to both, so you usually (but not always) need a wider breaker.

Unfortunately, the naming used by various manufacturers is not consistent.
 
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Old 03-28-05, 09:18 AM
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From my experience, any circuit breaker that is the same width as a normal single pole (120v) breaker will only be able to provide 120v. It has to be the same width as a two-pole breaker to bite onto both legs of the juice.

General electric makes single-pole breakers that are 1/2 the width of a standard singl-pole breaker, so you can fit two of them in the space of one normal breaker. But, again, they can only give you 120v.

Juice
 
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Old 03-28-05, 11:13 AM
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Some GE tandem breakers in some GE panels can be installed a half-slot off of the normal position and deliver 240 volts.
 
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Old 03-28-05, 11:14 AM
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Wow, I did not know that. I guess that's handy to know. Thanks. Juice
 
  #7  
Old 03-28-05, 11:50 AM
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Originally Posted by John Nelson
Some GE tandem breakers in some GE panels can be installed a half-slot off of the normal position and deliver 240 volts.
That would kind of screw up breaker placement in your panel. Unless you could buy a 1/2 breaker to fill that 1/2 slot above and below.
 
  #8  
Old 03-28-05, 02:37 PM
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I have one of those GE panels built for half width breakers in my apartment and it doesn't really mess anything up. The double pole breakers are spaced down one (half) space from the top by a single pole breaker. In my case, the two kitchen GFI circuits are on each side at the top. Half width regular breakers, GFI receptacles. (But I'm thinking they don't need to be that it is a "user friendly" arrangement.) Then the double pole breakers (half width also - 1" instead of 2" for the double pole) down each side, then the rest of the single pole breakers. I opened up the panel a while back when someone here mentioned the wire jumble that comes from using half width breakers, just to see what the wiring looks like... It wasn't gorgeous, but far from a jumble - I build tube guitar amps and there's plenty of room in one of those panels for decent lead dress if one takes the time. I'm thinking of going with a similar GE panel with the rewire I'm planning for the house I've purchased...

Anyone have thoughts on the use of half width breakers in a panel made for them?
 
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