Electrical Questions? Ask an Electrician Online.
Hello. Welcome to Just Answer.
A circuit breaker, whether double or single, with "20" stamped on it is rated for 20 amps. The difference is a double breaker will put out a total of 240 volts, and a single will put out 120 volts.
The double has 2 hot wires, and reading between them with a meter will show 240.
The single has 1 hot wire, and reading from that wire to a ground or neutral wire will show 120.
What is the voltage rating of your heat mat?
I haven't bought it yet, but it looks like it comes in 120V and 240V versions. Here is an excerpt from the installation manual...
Remember:• Do not exceed 15 amps at 120 VAC (1800 watts) or 15 amps(3600 watts) at 240 VAC through a single SunStat.• Select either 120 VAC or 240 VAC depending on the poweravailable. DO NOT mix voltages on the same SunStat if morethan one mat is to be installed to cover an area.• Load no more than 12 amps on a 15-amp circuit breaker, or15 amps on a 20-amp circuit breaker.
Based on that description, it sounds like the equipment can be used with either voltage.
I'm going to check the circuit voltage. I checked it earlier with my MM set at 200V and it said OL. I'm going to set it to 500V and check. I'll be right back...
Ok, it is 240V by golly. I didn't realize these circuits would be 240V. I just assumed US household electricity is 120V throughout.
Single breakers are. Doubles are 240.
Good to know. So, do you think my setup as described satisfies the manufacturer's requirement, or do you need more information?
Well, the description sounded like it was for a thermostat. But I would like to know for sure that the heat mat itself can handle 240. Can we pick this back up in a couple of hours? I need to sign off to attend church, but will be signing back on immediately afterward.
Yes, no problem. Thanks Jason.
Thank you. Talk to you soon.
I've included a screen shot from the manual showing the specs. Hopefully that helps.
And I think you were correct about my 1st excerpt. I think they were definitely talking about their SunStat control, which is the thermostat required to go with the mat.
According to the screen shot, it will work with either voltage... meaning you can connect it to a double pole breaker OR a single pole breaker.
Thanks Jason. That pretty much tells me what I need to know. Unless you have any parting thoughts, I'm going to sign off.
Other than letting you know you can contact me for additional help if necessary, I can't think of anything else at this time. I do appreciate the opportunity to help.