What is the purpose of the twin single pole breaker?

Question

I just moved into a rental property and was doing some electrical work such as replacing ceiling fans and outlets (reimbursed of course). When working with the breaker box, I encountered breakers I have not worked with before and frankly seem dangerous. As in, you can have to flip both half switches before the breaker is off. That and there seem to arbitrarily be white plastic clips place thru out to help turn both off at the same time. Honestly, most just seem to be missing with age.

I have yet to remove one from the panel, but so far I cannot find them online to see what they are. I'm under the impression the house was built in 92', but already I've been finding what I believe to be electrical violations, even for 92', every time I pull off a wall plate or fixture.

What are these breakers and should they be replace?

Also, a well pump is positioned between two breakers. This really feels like someone was cutting corners too. That and whom ever label the panel put GFI #1 and GFI #2, which went to the bathrooms that had nothing close to GFI (Just cheap 50¢ outlets). Needless to say those have been changed out.

Answer 1

Some things don't need common trip, they just common maintenance shut off. A 2 pole breaker provides both these things but not everything needs that.

The white things are called handle ties. You wouldn't expect to find them on every breaker, just the ones that need common maintenance shut off.

The two Breakers in one space are exactly what it says on the tin. They are separate Breakers with separate trip. I have never seen double stuff Breakers with handle ties, but if the manufacturer supports it then okay.

One thing that does need common trip is the pump. That should not be on a double stuff with handle tie. That should be on a 2 pole breaker. Now they do make quadplex Breakers which are two double-stuffs with a proper two-pole breaker in the middle; all that will fit into 2 spaces. That is what they should have used in that location.

I certainly hope that you tested the bathroom receptacles to see if they already had GFCI protection before installing a GFCI receptacle for no reason. Putting a GFCI on a GFCI is a waste of money. None of the breakers in that panel are GFCI Breakers, in fact there's no such thing as a GFCI double stuff.

Answer 2

Electricians usually call these double stuff or tandem breakers (tandem is what the manufacturer calls them). Not full height. Each breaker controls 2 120v lugs from 1 standard breaker position. Using 2 adjacent breakers with a pin creates a 240v circuit or possibly a multi wire branch circuit( MWBC is a circuit with 2ea 120 hots and only 1 neutral and 1 ground) the top switch on each breaker controls the top lug. Many years ago it was legal to use the pin to connect the breakers this is no longer legal to do but updating the panel is not required. Note square D still sells these tandem breakers today in 15,20 &30 amp models. For the last few code cycles the limit to the number of breakers in a panel was removed so we put in panels that can handle 40+ breakers and don't need to use tandems.

Answer 3

A normal US residential supply has two hot lines (sometimes called "legs"), which are 180 degrees out of phase with each other. If you connect a load between one leg and neutral you get 120V. If you connect a load between two legs you get 240V.

The phase difference also means that if loads are placed on the two different hots, their neutral currents will be in opposite directions. This leads to a construction called a "multi wire branch circuit". Such a circuit has two hot conductors on different legs and a neutral conductor shared between them.

A circuit with multiple hot lines is required to have "common maintenance shut-off", that is the means for shutting off the circuit must shut off all legs of the circuit. This is important because if only one of the hot lines is disconnected and then the neutral conductor is disconnected the neutral conductor can become live.

In some cases, a circuit is also required to have "common trip". That is a fault on one hot leg should disconnect all hot legs. This is needed if the circuit will support both 120V and 240V loads to avoid a back-feeding situation after the breaker trips.

To facilitate these requirements boards are designed so that adjacent slots are on opposite legs of the supply. If you need "common trip" then you have to use a purpose made double-pole breaker, but if you only need "common maintenance shut-off" you can use what are known as "handle ties" to tie together two adjacent breakers.

Standard breakers in the US are quite wide, wider than is really needed for low current breakers and US properties tend to have a lot of circuits. So manufacturers made "double stuff" breakers. These are two independent breakers in one unit and occupying only one slot, thus saving space in your panel.

Since a double stuff breaker fits in a single slot, both halves are on the same leg. So a double stuff breaker can run two 120V circuits, but it cannot on it's own run a 240V circuit or a MWBC. That is why the handle ties in your board are placed between two adjacent double-stuff breakers rather than between the two sides of the same double stuff breaker.

Answer 4

Not sure how much you know about how breaker boxes are set up internally. Ganged breakers are quite common.

To get ~220V in the US one can use a double-height breaker (like in slots 13/15 labeled Range). Or one can use two separate but adjacent full-height breakers which provides one breaker on each of the two different phases/busses. (The busses alternate each full-height breaker slot, so adjacent full-height slots are on different phases.)

In your case you have no full-height breakers ganged that way, however, you've got adjacent half-heights THAT ARE IN SEPARATE SLOTS which perform the same function.

Now, the one marked PUMP seems OK. I suppose the pump operates on 220V. But the others seem questionable.