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How many of you have used double pole breakers?

Are double-pole breakers just two single pole breakers physically joined?

Someone stated that only one side of the double pole breaker provided short circuit protection.

Picture below is the exact GE model. Anyone familiar with it? Does only one side trip?

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The person who tested the 2-pole breaker to have only 1 side tripping is an US citizen who has done many tests with it. See the middle of this blog. http://myphilippinelife.com/philippine-electrical-wiring/comment-page-1/

Could it be a counterfeit product?

Quoting him:

"The assumption that the two halves of DP breakers can serve as SP breakers proved to be very wrong. The double-pole breakers are NOT just two single pole breakers physically joined. We found this out the hard way when we had a total short in one of our circuits and the 20 amp breaker did not trip, but instead melted a #12 AWG wire. This must have been a huge overload, far beyond 20 amps.

We then tested the breakers on a test circuit. We found that only one side of our double pole breaker provide short circuit protection. It’s unknown which side may provide over current protection. Presumably, breakers made to be used as single-pole provide both protections in a single breaker, as do double-pole breakers used as a unit."

I need to know this because I'm powering up 240v load and there is ground wire to the enclosure. If not both can trip, what would happen if the live line that shorts to the enclosure is connected to the breaker side that doesn't have short circuit protection?

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    \$\begingroup\$ There are some “2pole” breakers that have protection on the phase side and the neutral is just a switch. Don’t expect the seitch to offer protection... usually obvious as one is thinner... \$\endgroup\$ – Solar Mike Nov 25 '18 at 7:07
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    \$\begingroup\$ I would, as a non-expert layman, expect a double pole breaker to be a breaker that cuts both sides if it trips. Nothing about that name suggests to me that both sides of the circuit have breakers in them, just that both sides get cut. That may be a bad interpretation \$\endgroup\$ – Passerby Nov 25 '18 at 7:10
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    \$\begingroup\$ Where did you find that comment? We can't analyze it out of context. \$\endgroup\$ – Dave Tweed Nov 25 '18 at 15:29
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There is no need for confusion, one just needs to read the specifications!

You have 1p breakers, one protected conductors.
You have 2p breakers, two protected conductors.
You have 1+n breakers, one protected conductor, one switched conductor, polarity sensitive.
And 4p or 3+N for three phase with or without neutral protection.

Look at the symbols.

One protected conductor.
enter image description here

Two protected conductors.
enter image description here

These symbols are printed on the unit.

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    \$\begingroup\$ The symbols on the 1+N tell even more. The tiny x says only the 1-2 switch has the 3/6/10kA switch-off capacity printed on the device, while the N-N switch has to be switched off under no current conditions. There is a mechanical arrangement to ensure that for the "normal" use case. \$\endgroup\$ – Janka Nov 25 '18 at 16:46
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    \$\begingroup\$ The X indicates it is a circuit breaker. Both have the T part, indicating a isolator/disconnect switch, and it is it not a simple signal switch without T part. \$\endgroup\$ – Jeroen3 Nov 25 '18 at 18:41
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There may be or may have been at some time, a legitimate use for a circuit breaker connected to a switch with a handle-tie. It would be more than unusual to find such an assembly offered for sale today. Such an assembly must not be offered for sale as a two-pole circuit breaker.

A two-pole circuit breaker is two circuit breakers that open simultaneously if either one trips. That is true whether it has one handle or two handles tied together. If a device is a two-pole circuit breaker with two handles tied together, the trip rating should be marked on each handle. There should be sufficient information marked somewhere on each breaker to identify each one as a circuit breaker if separated.

It is not a good idea to install any circuit breaker that is not purchased new. Even purchasing new-old-stock circuit breakers is less then the best idea.

PS

In my first paragraph, I was referring to circuit breakers of the type mentioned in the question that plug in to North American distribution panels. I believe the 1+N breaker described by @Jeroen3 in another answer refers to stand-alone circuit breakers.

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    \$\begingroup\$ That may be true in the US domestic market where split phase is a thing, but it is far from true in general. A breaker/switch combo is very useful as it provides a means of isolation in a single phase with grounded neutral situation which a single pole breaker does emphatically NOT provide (Neutral is a current carrying conductor you should really isolate it as well as the phase conductor before working). Having a breaker that can also serve as an isolator can be a win in things like panel building, but as ever you have to understand your application and what risks you are protecting against. \$\endgroup\$ – Dan Mills Nov 25 '18 at 19:06
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A two-pole circuit breaker is effectively two single pole breakers with their handles tied together, so that when either breaker trips, both will be turned off.

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  • \$\begingroup\$ Pls read updated post above. Someone has tested the GE TQL line and he confirmed only one side of the 2 pole offers short circuit protection. \$\endgroup\$ – Jtl Nov 25 '18 at 6:18
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    \$\begingroup\$ "Someone!?" not even username on xyz internet site? \$\endgroup\$ – Charles Cowie Nov 25 '18 at 16:16
  • \$\begingroup\$ Pls see edited main post for the identity of the person and the tests. \$\endgroup\$ – Jtl Nov 25 '18 at 22:12

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