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Electrical Help

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  • Electrical Help

    I just got a nice big electric heater for the shop, and I had a quick (hopefully easy) question about hooking it up.

    The instructions for the heater mention three wires, black, white, and green. My 220 circuit has 4: black, white, red, green. What do I do with the red one? Is it necessary?


  • #2
    Is the heater 110v or 220v? It sounds like it is 110v if it only has 3 wires and if so you wont want to hook it up to 220....bad things WILL happen!
    "Hey you dang woodchucks, Quit chucking my wood!"


    • #3
      I am guessing that have an existing 240 circuit in the wall/outlet box that is 4 wire. Typically your red and black are two legs of 120v service and green is your egc with white typically your neutral. You can test this with an voltmeter set to 120vac and touch your leads to the white and either red or black. You should get a 120v reading if everything is setup as standard 240v wiring. Often times the white conductor is included to allow for the flexibility of having 120v service in the same conduit or run. 240v service needs no neutral. HTH

      Chad beat me to it and raises the more important issue, check your heater specs!
      Last edited by chopnhack; 10-30-2010, 10:08 AM.
      I think in straight lines, but dream in curves


      • #4
        It's definitely a 220 heater. I saw in one review that the wiring instructions may be wrong (someone mentioned that the instructions were for 120 instead of 220).

        I attached their instructions.

        FYI, it's this heater:

        Here's the mention of it in the review I was referring to, if this makes more sense:

        The instructions for wiring the heater are very poor. It illustrates how to wire for 120V but not the 240V. You will only need a 3 wire plug (same as Driers or Stoves) with the Red and Black hooked to the 2 power leads (black and white in the instructions) and then white/ground to the ground.
        Attached Files
        Last edited by Cubsfan; 10-30-2010, 10:22 AM. Reason: Additional INformation


        • #5
          are you planning on hardwiring direct into a junction box or installing a pigtail to the heater to plug in to a receptical?....
          also this might help (

          maybe post a pic of the wiring block on the heater, I couldnt find one online.
          "Hey you dang woodchucks, Quit chucking my wood!"


          • #6
            Web site shows it hooked for 208 or 240 volts.

            Unless your home is an industrial complex, you will have a nominal 240 volts. Just use a meter and make sure you are supplying 240 volts where they are calling for the black and white wires.
            Sometimes the old man passed out and left the am radio on so I got to hear the oldie songs and current event kind of things


            • #7
              Picture attached.

              From everything I've read, seems like the black and the red should be attached to the power terminal block, the green to the green screw, but I'm not sure about the white. Then again, I'm not 100% sure about the other ones either

              Thanks for all the help!
              Attached Files


              • #8
                You have it wired correctly: Red and black are hot, green is ground.

                Your heater doesn't require a neutral so you don't need to / can't wire it in. Just cap it with a wire nut and leave it alone.
                Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison


                • #9
                  You can verify that by looking in your breaker box and seeing what color wires are attached to the 220 breaker for that circuit. It should be the black and red.
                  "If all you have is a hammer, everything looks like your thumb."


                  • #10
                    Your picture doesn't look like you have it wired in yet. On the bottom right, where it says L1 and L2 (stamped into the silver plate) there are two lugs, one for each "line". Back out the screw on each and put the black under L1 or L2 and the red under the other, tighten the lugs down real snug, dont overtighten to cut into the copper conductor. The green screw will be where you terminate your ground conductor. You may need a ring or spade terminal to crimp onto your wire as it is probably 10gauge and wont fit under that screw well enough.
                    Last edited by chopnhack; 10-30-2010, 08:48 PM. Reason: 10g would be your l1 and l2 the ground would be smaller and would fit, sorry
                    I think in straight lines, but dream in curves


                    • #11
                      Thanks for all the help! I got it installed and it seems to be working (not going to heat things up on a 75 degree day like today though )