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240 wire for the shop

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Forum topic by mahdee posted 11-13-2013 12:52 AM 1328 views 0 times favorited 16 replies Add to Favorites Watch
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mahdee

3553 posts in 1233 days


11-13-2013 12:52 AM

I have ordered a 240 volt heater for one of my shops that has also a 240 welder in it. I am thinking once the heater arrives, it will not plug in to the welder outlet. Is there a way to remedy this without having to run an extra 220/240 wire in the shop?

-- earthartandfoods.com


16 replies so far

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crank49

3981 posts in 2436 days


#1 posted 11-13-2013 02:05 AM

Yes.
Are you talking about a stationary 240 volt heater like a ceiling mount unit?
You could make up a special purpose extension cord for the heater if it has a cord with a plug on it.
Just make a cord with a jack to match the heater power cord on one end and a plug to match the welder outlet on the other end.

If the heater has no cord and was intended to be hard wired just make a cord for it that terminates on the lugs where the power is supposed to be connected and put a welder plug on the other end.

The size of the cord may be a problem. It should be the same size and gauge as the power cord on your welder, which should match the size of the breaker supplying the welder outlet.

For example, if the welder breaker is a 40 amp 240 volt breaker, the wire would be at least 10/3 gauge. There is an allowance for power cords in open air that allows you to use the next smaller gauge than what is indicated for wires inside a wall. Inside a wall this wire would have to be an 8/3 gauge.

Also, every local building authority has the right to make these rules more strict than the NEC standard code.
Check with a local electrician.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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mahdee

3553 posts in 1233 days


#2 posted 11-13-2013 01:41 PM

Thanks Michael. This is the heater I am getting. It does have a 6’ power cord. Fortunately, I live out in the country and there are no zoning here; nevertheless, safety is just as important. I will have to check out the outlet and go from there. Thanks again for your input.

-- earthartandfoods.com

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crank49

3981 posts in 2436 days


#3 posted 11-13-2013 06:33 PM

So it’s 4800 watts at 240 volts.
4800 / 240 = 20 amps.
A 12/3 wire would handle the amps, but just barely.
Still, to be safe you need to match the capacity of the breaker that feeds the welding outlet.
I suspect the best match would be 10/3 wire. It would certainly handle the heater.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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DrDirt

4169 posts in 3207 days


#4 posted 11-13-2013 06:55 PM

Agree with Crank on the 10/3 wire

I have the Farenheat unit 5000W from Northern tool -
I put a plug on it, but it is supposed to be hardwired in. I is on its own breaker that only supplies power to that outlet box – so there isn’t the possiblity having too many things on the circuit.

There is concern that if there were ever a fire – would having the plug give me insurance woes.

-- 'Political correctness is fascism pretending to be manners' ~George Carlin

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mahdee

3553 posts in 1233 days


#5 posted 11-13-2013 07:01 PM

Thanks guys,
I rarely use the welder and it is unplugged when not in use. I wonder if I can use the welder outlet as a junction box and run the 10/3 wire from there to another outlet. Or do you think my best bet is to go ahead and run an independent 240 from the fuse box? My only problem with that would be routing it. I may be able to go through the ceiling if the studio where the breaker box is and come out through the shop wall.

-- earthartandfoods.com

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GFYS

711 posts in 2936 days


#6 posted 11-13-2013 07:02 PM

not if the receptacle and plug is rated for 30 amps

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mahdee

3553 posts in 1233 days


#7 posted 11-13-2013 07:04 PM

Yes. It is 30 amps. So will go from the box with its own breaker. Thanks again.

-- earthartandfoods.com

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crank49

3981 posts in 2436 days


#8 posted 11-13-2013 09:35 PM

Huh ? ?
I thought this whole discussion was based on using the existing welder outlet for running the heater.
Which is perfectly legal and safe, by the way.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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GFYS

711 posts in 2936 days


#9 posted 11-13-2013 11:27 PM

I was talking to DrDirt re: There is concern that if there were ever a fire – would having the plug give me insurance woes., sorry

View TopamaxSurvivor's profile

TopamaxSurvivor

17671 posts in 3141 days


#10 posted 11-14-2013 04:44 AM

That heater requires a 30 amp circuit and #10 wire. .8×20 = 16×240 = 3840 watts is the maximum continuous load on a 20 amp circuit. Heating equipment is considered a continuous load.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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DrDirt

4169 posts in 3207 days


#11 posted 11-14-2013 06:16 PM

Thanks mics…. after your post – I realize that although each of the 3 recepticles are wired with 10 guage wire – they are all on 20 Amp plugs/recepticles.
Same with the table saw and compressor.

Suppose – I have a little weekend job to do. But also the heater itself says it is supposed to be hardwired in.

I don’t understand why all the 5000 W heaters mandate hardwiring – but the 5600W version has a NEMA plug – NEMA 630P. Same with the clothes dryer and Stove – - they all have plugs. WHat makes this heater special?

-- 'Political correctness is fascism pretending to be manners' ~George Carlin

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TopamaxSurvivor

17671 posts in 3141 days


#12 posted 11-15-2013 03:30 AM

WHat makes this heater special? Most likely the UL listing procedures and the manufacturer’s instructions for use.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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DrDirt

4169 posts in 3207 days


#13 posted 11-15-2013 07:53 PM

Thanks Topa – -my thoughts were initially that 5KW heaters (and higher) maybe had to be hardwired…. then I see the 5.6KW using a NEMA plug (30A – - so I should change mine regardless. They are all electric element wall mount garage heaters.

If it is a dedicated circuit to one box – - is it an potential Arcing issue? where hardwired is going to be safer?

I went with the plug because my shop is a 1 car addition to the house that had already a two car attached garage, and I can if I am working on the car, move the heater to the 2 car garage side. (~2X per year) The two areas kept the insulated wall and door between them.

-- 'Political correctness is fascism pretending to be manners' ~George Carlin

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mahdee

3553 posts in 1233 days


#14 posted 11-15-2013 09:54 PM

This thing actually has a weird looking plug. The two upper ones are side by side like this: . The ground is normal. NEM #6-30P

-- earthartandfoods.com

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TopamaxSurvivor

17671 posts in 3141 days


#15 posted 11-15-2013 10:20 PM

If properly done, I don’t think one is safer than the other. The mfrs just listed one as a portable unit and the other as a permanently installed unit.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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