We are trying to wire 3 baseboard heaters (all 240V: 750W, 1000W and 1500W, in parallel) attached to a douple pole 20amp breaker. We tried 12 gauge 2 wire first and they were working but not much heat. So someone told us maybe we'd only wired them using 120V(? ). So we now have re-wired them using 3 wire, all different ways and no luck. We have since learned from reading here that 3 wire isn't need as baseboard heaters require no neutral so we ignored and capped the neutral at both ends, still no luck!
Winter is coming and we are in a mad panic to figure this out as the new heaters are our only source of heat.
Could someone please explain in laymans terms exactly how to properly hook them up to each other and to the double pole breaker as well as how we can test or know that we are running 240volts and not 120volts.

Many thanks and appreciation in advance, we have become very frustrated!
Shelby

If your heater is 220 volts, I highly recommend installing a double pole thermostat.

Installing Electric Baseboard Heat (DIY Electrical Wiring Help - Answers to your Electrical Questions)

220 V baseboard heater wiring - Electricians Forum

You are sure it is a double pole breaker, 2 contacts to the breaker box busses and not a tandem one with 2 circuits from one contact?

To start, can you provide a picture of the panel, and point out the breaker for the heat?

You will also need a voltage tester to measre across the wiring you have installed to the heaters.

Does your "double-pole breaker" have a bar that connects both poles together? If it doesn't you may have bought the wrong kind of breaker.

Yeah, the lack of a bar is another clue it is a tandem breaker. The more I think about it, if you are getting some heat, you have wired them up in series.

You have 2 feed wires coming into your house each 120 volts above ground and 240 to each other. Each one connects to a different buss running down through the box. A properly installed double pole breaker will connect each wire from it to a different buss. So power flows from one buss in the breaker box through the breaker to one pole of the double pole thermostat and when closed on to the heater. There, it needs to flow into one terminal, through the element, and back to the thermostat, and back to the other contact in the breaker, and finally to the opposite buss.

Several things can go wrong. With the wrong breaker, both the out going contacts connect to the single feed contact, the tandem breaker. Some boxes are set up with slots 4 and 6 both connected to the same buss. I think this is where TK is going. The solution there is to use 2 and 4 or 6 and 8. If you connect the second wire to the neutral bar at the bottom, you will only have 120. The last case is wiring them in series. That is harder to explain.

Try just wiring up the first heater. If it then gives the full heat, you had them wired up in series. With : as contacts and = as wires, the breaker, thermostat, and 3 heaters needs to look like this, :=::=:=:=:

The meter TK suggested is a good idea. If you don't have 240 volts between the contacts on the breaker, no sense doing anything with the rest of the circuit until you do.

We have heat! We think it was bad breakers. We just hooked up a double 30 amp breaker and the heat is pouring out. I know we should use a 20 amp but can we use a 30 amp?

Thanks for the help!

Very good. Since the circuit is wired up with #12, you must use a 20 amp breaker. Look for one labeled double pole, and 2 contacts to the buss, and a bar between the handles or a single handle. Best to go with the same brand as your breaker box.

Lesson #1, always start at the breaker, or what ever feed there is.

The 30 will work OK for temporary purposes, day or so, as long as no more load is added. I am not worried about overload, the current will remain at 13.5 amps, and the breaker will still protect for short circuit.

I am curious how a bad breaker could cause reduced power without producing about as much heat as the heater was putting out.

Easy, a bad connection can easily turn into a high resistance heating element type load, create a small amount of heat at the beginning, and as it deteriorates get progressively worse.

This resistance can drop a significant voltage drop, sometimes just barely touching or conducting electricity. This vd can cause another load in series to act odd, or run at low power.

Do a search for lose electrical connection, there is a wealth of information available. There are entire businesses looking for loose connections before catastrophic damage is done. Have IR camera, will travel.

Also, you may be interested in doing a search on infrared inspection, see what a loose connection looks like in color infrared, and the temperatures of those hot spots.

Infrared is not the cure, only a one part of analyzing a hot spot. While Ir helps find the problems, other instruments are used to determine the actual problem to effect corrective measures.

This service is a big part of my everyday at work, so if there are any questions about the loose connection, detection, and repair of them, I will be happy to help.

It seems to me that unless the bad connection was so high resistance, it really knocked the power down, or was rather low, you wouldn't need the IR camera to find it.

At times your correct, you can either feel it or smell it. Other times, nothing.