[14u2c]

The easy answer sometimes is not if? you are running puny extension cords but how long?
I don't know how many times a cheap #16-3 50 ft chines extension cord can cause an extra 10-15 amps of draw. Although theoreticaly you should have a larger breaker there should be plenty of built in "extra"

TRY NO EXTENSION CORD

Yeah if you have a siemens or sqd you can go get a 30 amp single pole.. cost about 12 bucks but even so if you turn both heaters on at the same time you are probably going to have too much amp draw and that one will pop also... just go get a extension cord 12 gauge and run it off that..

[14u2c]

yeah if you have a siemens or sqd you can go get a 30 amp single pole..cost about 12 bucks but even so if you turn both heaters on at the same time you are probably going to have to much amp draw and that one will pop also...just go get a extension cord 12 gauge and run it off that..

Duh had to modify this after I thought about it forget the 30 amp single pole your wire probably is only 12 gauge which I only rated for 20 amps.. so like I keep saying use a extension cord or have another circuit put in that runs off a new breaker..

[14u2c]

They never say they are running an extension cord but always are and you know the quality most people use. . . Silly? maybe. but line loss is a big problem. I give up! put in another breaker. Me I would use an amp meter and measure the amp draw. some of you experts should try it with and with out 50 ft of chinese 16 gauge extension cord you might learn something. PS 12-2 with a ground is 12-3.

You 12 2 extension cord is 12 3 but you never say a "gound wire" is a actual wire in the world of romex.your going to go make this man pick up 12 3 romex and confuse him with too many wires.. that he does not need... 122wg romex or 12 3 extension cord is what you need..

[14u2c]

You're right labman, I should have left this one alone. :rolleyes:
This is only true for inductive loads like motors, not resistive loads like space heaters.

Amp draw is amp draw this thing still suck a lot more amps when they start up just like a motor they spike in amp draw and then when reach a desired temp the trim back off to a running amperage..

[donf]

What in Heaven's name is going on here? This post qualifies as moronic for all the garbage responses. <deleted cheap shot>

2heater - I understand your concerns, you have been given a bucket full of swamp gas.

Let's go back to the environment you have. As I understand it you have two heaters that each draw 15 Amps connected to one 20 Amp independent (or dedicated circuit)

Your situation is that the breaker trips every time both heaters are turned on simultaneously, correct?

The area you are trying to heat is a garage so that your family can use this area as a playroom during the winter.

Labman very correctly pointed out to you the step one would be to insulate the garage to keep the heat in, very good decision.

As to the electrical problems.

A heater is defined as a "Constant power or Continuous On" device. As such, the Amperage available for this device must be 125% of the listed Amperage.

15 X 1.25 = 18.75 amps, NOT 15 AMPS. So each heater should be attached to its own 20 amp circuit, not joined on the same circuit.

Each 20 Amp circuit will require a 20 amp SPST Breaker. 12/2 NM cable and each should have a 20 amp receptacle installed in the wall where it is needed.

Just taking an extension cord and plugging it into another outlet buys you nothing unless that receptacle is on a 20 amp circuit, which it seems no one bothered to tell you!

Do you have any 20 receptacles installed in your residence? Yes youi do. <The two small appliance circuits in the kitchen should be 20 Amp according to current NEC Code.> Edited additional information

Calling cable Romex is like calling tissue paper Kleenex. Romex was a company product name for Non Metallic Cable.

12/2 cable is defined as two insulated conductor cable with a bare ground. The conductors are colored Black (Phase) and White (Neutral or Return).

12/3 is defined as three insulated conductors. Black (Phase) - Red (Phase) and White (Neutral) and an bare copper ground wire.

The 12 Is the AWG (Which stands for American Wire Gauge) 12 AWG is listed for no higher than 20 amps.

14 AWG is listed for no higher than 15 amps.

For example using a 14 AWG cable on a 20 Amp circuit may create a fire condition for you.

Please let me hear back from you so we can actually help you.