Extension cord for 220V?

Gary_in_Indiana · Apr 29, 2003

I don't know if this is common or impossible so I thought I'd ask here. If I were to want to use my 220V welder further from an outlet than it's cord will allow could I use an extension cord?

I realize that most extension cords don't have the proper plugs/recepticles for this but assuming I changed those to work and used the proper size/gauge wire is this an option? The wire from the box to the outlets is 10/2 and is on a 30 amp breaker per the welder manufacturer. Does that mean that 10 gauge extension cord would work?

I know that this seems logical but I don't want to rely on that alone when dealing with electricity and wood frame buildings. /forums/images/graemlins/crazy.gif

JATO_RaT · Apr 29, 2003

Easily Gary. Using a #10 wire is great. I suggest you keep the length down to about 50', that however is entirely dependent on the amperage or cuerrent demand for the device you use. A welder is pretty high. It's easy to figure voltage drop which is where extension cords start to become a problem. You can use a regular 120V cord, that is a cord with a white/black/green wire as a 240 volt cord. The white wire will become a hot leg instead of the neutral it's used as in a 120 V application. Identifying it as a hot wire with a wrap of black tape is all that code requires. The plug connections will also need to be changed to reflect this. I prefer using twist lock ends for all my applications. I have a couple of 240 cord setups that work for my welders, my table saw etc. All now have the same ends. By using 240V plugs and receptacles, there can be no mistaking the voltages, a 240V plug will not fit into a 120V and vice versa. Rat...

Mrwurm · Apr 29, 2003

I bought 220v extension cord for my welder at the old 'Farm-n-fleet'. It already had the right plugs. It is 25ft long and rated for 40amps. I think I paid $30. Made by Century.

Mrwurm · Apr 29, 2003

here's one on ebay

It will cost you more $$$ to make your own than to buy one. Probably cost about $40 to make one.

knucklehead · Apr 29, 2003

I debated replying...but here goes. Electricians feel free to whack me...... /forums/images/graemlins/blush.gif

I wired my garage for 220. Because everything is a work in progress, and I wanted to use the welder NOW, and I am cheap and didn't want to cut a few feet off and waste it on a temporary receptacle location, I wired the receptacle to the end of the coil that was eventually supposed to go around the back to the (future) welding table, hung the coil on the wall and used the welder.

That was 15 years ago.

When I want to weld in the driveway, I uncoil the wire, gently lay it down, and go to the job with the welder. I am very careful not to abrade the covering, and I usually loop or unroll the coils instead of pulling on them, because I do not want to flex the copper too much. I assume there is a reason extensions are not solid conductors, and that is not only for flexibility, but to avoid fatigue breakage. I also backfeed the house with this setup when it becomes necessary to use the generator. All of this will be changed very soon, as the garage is going to have its turn as the focus of home projects, and the wiring will be re-done to place a subpanel in the garage.

Now, I said all that to say this: Most welders I know use extended leads, not extended supply cable. Since voltage drop is the consideration in determining wire size, I would intuitively think extending the lower voltage carrying leads would be more economical than extending the supply cable. Can anyone comment on this? Or does the price of welding leads make using an extension cord economical in home applications?

JATO_RaT · Apr 29, 2003

"Now, I said all that to say this: Most welders I know use extended leads, not extended supply cable. Since voltage drop is the consideration in determining wire size, I would intuitively think extending the lower voltage carrying leads would be more economical than extending the supply cable. Can anyone comment on this? Or does the price of welding leads make using an extension cord economical in home applications? "

It is more economical to extend the higher voltage then the lower voltage cables. The lower voltage is where the significance of the voltage drop is most dramatic. I don't want to get technical, but look at those power poles outside your house, they typically carry about 12000 volts on the top wires. From there they drop to a transformer which more often then not drop the voltage to 120/240V. Why not just bring 120/240V from the generation plant and eliminate the transformer you might ask. Well, you could, but the wire size would be about the size of a 6" PVC pipe, cost a fortune, break the poles, and at that, the voltage drop would still be significant. Those little tiny wires with 12000 volts in them is all it takes to bring all that power to you and all your neighbors and have minimal voltage drop.

So to answer your question, extending the low voltage cables of the welder even 50' requires significantly larger cables. Extending the supply side or 240V side would not require any increase in size. Its a matter of convenience, extending your welding cable leaving the welder where it is, is often times is far easier then to bring the welder where you are and run a cord to power it. Rat...

knucklehead · Apr 29, 2003

Duh! I was thinking about it bass ackwards! The pipe analogy I usually use did not help me - I usually find it helpful to convert things to mechanical visualizations. I forgot good old eye-squared-arr. Losses vary as the square of current, and for a given wattage, it takes more amps at a lower voltage, hence greater losses....

I get a lot of ribbing, being a mechanical sort in an electrical utility.....they keep me in the cellar.

Slinking away humbled /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif

thcri · Apr 29, 2003

</font><font color="blue" class="small">( You can use a regular 120V cord, that is a cord with a white/black/green wire as a 240 volt cord. The white wire will become a hot leg instead of the neutral it's used as in a 120 V application. Identifying it as a hot wire with a wrap of black tape is all that code requires.)</font>

RaT,

Not in Minnesota. That would be illegal. In fact all circuit plugs now have to have 3 wire plus a ground for 240 volt 1ph. When moving my welder to my new house I had to have a new cord installed on it because my old one only had three terminals. I had to do that with my clothes dryer also. There is 4 prongs on all the new ones installed in my house. But what I am thinking is this came from the NEC which is National so I would think you would be running into this also. Now I do realise that your house is wired with the old ones and so is the welders you are talking about.

just some information.

murph

JATO_RaT · Apr 29, 2003

Murph, you are quite correct as it applies to devices that use 120/240V. The same applies in CA where clothes dryers once got away with using the ground as a conductor to operate such devices a 120V timer or light bulb. Todays dryer circuits require a four prong receptacle and 4 wire cable. A range also requires the new 4 prong plugs as well. It never made any sense to me that ground would ever be allowed as a conductor. For a 240V only device such as a table saw, air compressor, welder, air conditioner etc., you can still use a 3 wire cable where two conductors are hot and the 3rd is ground. There is no need to consider a neutral since 120V is not needed. Many well pumps are also done this way. It is confusing. Rat...