A/C Disconnect

Is this really a 2 pole breaker that takes 2 slots or a single slot tandem breaker on one phase rail?

It is a General Electric 30 Amp, 2 Pole Thin Type THQP General Electric Circuit Breaker Model THQP230

Pull the breaker out and be sure it is actually hitting 2 rails. Some small GE panels only have 240v on the center two positions and one rail extends horizontally out from there. I have one of these in my garage.

There is a horizontal bar, with a smaller vertical bar below it. the breaker has a large split down the middle, two smaller connectors which line up with the vertical bar. All appear to be contacting properly. Is it possible that because the neutral wire is not attached to the neutral bar (because the disconnect doesn't have a way to connect it) it is not operating correctly. I am just perplexed because each hot is drawing 120, but i can't get the 240 to show.

The red wire should go to 1 pole on the breaker, and the black wire should go to the other pole.

And the white wire is ...?

1) RE: not sure if your volt meter is broken

If you know how to do this *safely*, connect a 120 volt,

60 watt test lamp to the load side red and black, then turn the Eaton on. If the bulb glows extremely bright or blows, your meter is bad. Or buy a new meter.

2) RE: possible to have 120 to ground from red and 120 to ground from black, but nothing from red to black?

Yes, it is possible if the wiring is wrong. At your main service panel, the power comes in like this:

120------0 A ground---0 B 120------0 C

I added the ABC labels. Voltage from A to B is 120; voltage from C to B is 120; voltage from A to C is 240.

A typical panel distributes the voltage so that 12/ the breakers are connected to A and the other 1/2 are connected to B, like this: A B B A A B B A etc

Your Eaton disconnect should be wired to an AB pair. If it is miswired so that both red and black go to A (or to B) then you will get the symptom you describe.

The double pole breaker in your main panel should have 240 volts across its poles.

Please be very careful with this. If you are messing around in the main panel or the disconnect, you are in danger. If you are unfamiliar with these, the danger is magnified.

Ed

You should read 240 (approx.) volts between the two hot wires. Make sure your tester is wroking properly first, you can try it on another

240 volt appliance outlet, such as a dryer or stove. If you are sure it is reading 240 volts like it should, then proceed with this next suggestion, if it is not reading, stop and get one that does work. If you are reading on the bottom of the disconnect, try reading on the top. If you read 240 volts on the top, then the disconnect is bad and needs to be replaced. Or if the disconnect has fuses, one is probably blown. Put your test leads across each fuse , you should read nothing with power on. If you read nothing between the top, or incoming wires, then go back to wherever this is fed from, you either have a bad breaker, or a blown fuse. This is probably fused in your main breaker or fuse panel. (The one for the whole house.) Or you could have a wire broken between the disconnect and the main fuse or breaker. You are reading 120 volts on each conductor to ground because the voltage is going from the "live" conductor, through the AC unit, back to the conductor that is "dead", through your tester, to ground. Pretty common problem. Hope this helps..

Yes, it is possible if the wiring is wrong. At your main service panel, the power comes in like this:

120------0 A ground---0 N 120------0 B

I added the A,N,&B labels. Voltage from A to N is 120; voltage from B to N is 120; voltage from A to B is 240.

A typical panel distributes the voltage so that 1/2 the breakers are connected to A and the other 1/2 are connected to B, like this: 1 A A 2 3 B B 4 5 A A 6 7 B B 8 etc with each number representing a breaker position and each letter the buss bar it is supplied by.

Ed I changed the labeling of your reply to make the labeling consistent and to mimic the breaker pattern most commonly found in North American panels. This change may make your reply easier for the OP to understand.

I'd also like to suggest that the OP go and buy a Wigington type solenoid voltage tester such as the one shown in this document.

There is a good reason that electrical workers are required to use them on the job rather than use a multi meter. A solenoid voltage tester places 10 milliamperes of load on the circuit in the form of the testers solenoid coil. The vibration of the solenoid is palpable in the tester and increases as the voltage increases. This leads to both a palpable and visual difference in disparate voltage readings and unlike high impedance multi meters a Wiggy will not falsely indicate a voltage from induction from adjacent circuits.

Yes! Much better! Ed

It's the wrong breaker. It contacts only 1 phase, and distributes that phase to two wires via the two poles. You need a regular width 2 pole breaker that takes up two positions in your panel - or you could use 4 "skinnies" in 2 positions with appropriate toggle ties. Easisest to use a regular two pole if you have the positions available.

Ed

Whoa whoa whoa! He said he has a "thin" GE breaker, which means it is the type that gives 2 x 1-pole breakers off of a single 1" slot. You CANNOT get 240V from that breaker, it is 2 x 120V from the same phase! The reason he is reading nothing now Line-to-Line is because there is no difference between the 2 breaker circuits, but both of them will read 120V Line-to-Neutral or Ground. There is nothing wrong with the meter.

What is needed is to put in a true 2-pole breaker, which will be TWICE the width of a 1 pole breaker. That way it will span the 2 phases of the load center bus bar and have 240V Line-to-Line. If you are out of slots, you need to buy a 4 pole breaker set which has 2 x 2-pole thin breakers configured so that the 2 on the inside make up 1 x 240V circuit and the 2 on the outside make up the other 240V circuit. If you need the other 2 circuits to be 120V, just remove the bracket that joins them together.

If you don't understand any of this, hire an electrician!

It still depends on which slot he uses in the panel. They do make a thin 2 pole but there are usually only a couple slots in a panel where it works. I have a small GE panel and there are only two 240v slots, the rest are on the same rail so you get 120v, no matter what breaker you use. The label says you only use single pole breakers anywhere but the two center slots.

WRONG!!

"tandem" vs "double-pole"

A single pole "tandem breaker" IS 2 breakers that will fit in an opening designed to fit one breaker. = same phase.

He listed the model# THQP230 = Q Line Circuit Breaker, 30 Amps, 2 Poles, 120/240 Vac. "Double Pole" Thin

That breaker will not fit a single 1" slot. It straddles the middle of two 1" slots connecting the opposite phase and only using "THE AMOUNT OF SPACE" not the opening, of a single 1" slot leaving spaces for a 1/2 single pole on either side.

If you don't understand any of this, hire an engineer!

Bob Ferapples wrote: