Electrical Question?

[Ellis Kinney]

How to explain this--- I have a 220 wall outlet that my Miller Thunderbolt plugs into. It has a round hole and two vertical slots, The right one longer than the left one. I just bought a new electric heater that has one round hole and two horizontal slots of the same size on the plug. I have been running my old electric heater with a 6 foot long HEAVY DUTY extension cord to get it to the center of my garage. I need to change the extension cord to match my new heater. The 220 extension cord has ground and a black wire and a white wire. How do I know which wire to hook to which of the two horizontal slots on the other end of the extension cord? I know this is confusing! Thanks, Ellis

 

[old]

Round is ground the other 2 are the hot leads so black and white go to the slot ones

 

[Audioguy]

With 220v both legs are hot, typically white goes to the larger blade.

 

[Steve@Advance]

If both screws are brass colored, it doesn't matter. Being it's 220v it won't matter.

Should it be a 120v circuit with a ground, a hot and neutral, the ground is green , the hot will be the brass color screw, the neutral the silver screw.

 

[buickanddeere]

 

[buickanddeere]

 

[dr sportster]

As you can see by Buicks post that there are a lot . You can push the male through cardboard to have something to take to the supply house to match. Two hots could go on either screw of the slots in receptacle.

 

[MarkB_MI]

Hmm. Is it possible your "220" extension cord is actually a 120V cord on which the ends have been changed? I say that because white is supposed to be neutral, and your cord doesn't have a neutral. It's OK to change the connectors, but make sure the cord is rated for 300 volts or more. Technically, I think you're supposed to mark the white conductor with red tape on each end, but nobody's going to check.

As for how to connect it to the new connector, it doesn't really matter because, unlike with a 120 volt cord, the polarity doesn't matter. Both hot conductors are 120 volts referenced to ground. On a 120V circuit, one conductor is zero volts to ground while the other is 120V to ground, so polarity matters with 120.

Personally, rather than use a six foot extension cord, I'd probably replace the cord on the heater with a longer one. Less connections means less aggravation. And rather than plug the heater into the welder outlet, I'd wire a second outlet on the welder circuit.

 

[Gary Mitchell]

I FIND THAT TAKING A PHONE PIC OF THE SUBJECT IN QUESTION IS HANDY. gm

 

[GarryinNC]

I may have missed it, but is your heater 120 volt or 240 volt.

Garry

 

[John T]

Ellis, as far as pure 240 is concerned, it doesn't matter which line conductor, L1 or L2, connects to which Hot pin/blade on a pure 240 Volt plug or receptacle..........

A pure 240 Volt plug or receptacle with a single round pin would use the single round for the Equipment GroundING Conductor (EGC) and the two other straight pins for the Hot UNgrounded Conductors, L1 or L2, which have 240 VAC line to line, and it makes no difference which side is used for which L1 or L2.

Often a pure 240 branch circuit consisting of two Hot UNgrounded conductors, L1 & L2, plus an Equipment GroundING Conductor, would use RED and BLACK for the Hots and Green/Bare for the EGC.

On a 120 Volt Branch circuit the UNgrounded Conductor (Hot) would be BLACK......The Grounded Conductor (Neutral) would be WHITE,,,,,,,,,,The EGC would be Bare/Green

If you have a cord that has Black, White, and Bare/Green conductors it may have been used for 120 ???????

Its possible to use the wrong color wire but I suggest you label the wires with a correct color of tape on the ends so in the future it can be identified. If I were doing that on a pure 240 cord I would re-label tape the two Hot UNgrounded 240 volt conductors Red & Black and the EGC Green

Use wires having sufficient ampacity and voltage rating.

Hope this answers your question and provides some electrical insight

John T