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View Full Version : What gauge to wire a 50 amp line?



jtybt
02-25-2010, 04:46 AM
I have a 20 amp 220 for my small welders but decided I might as well run a 50 amp along side. It's just a 25' run from the service box. I have plenty of 12/2 romex around but wasn't sure what would be appropriate for a 50 amp line.

TIA


P.S.
I now have a 225LX and waiting for a PP50

Ray
02-25-2010, 05:43 AM
Technically 12 Ga. will handle 50 amps, but I would go with at least 10Ga.
Here’s a link to calculate minimum conductor sizing.
http://www.elec-toolbox.com/calculators/voltdrop.htm

rinktumbody
02-25-2010, 05:45 AM
I have a 20 amp 220 for my small welders but decided I might as well run a 50 amp along side. It's just a 25' run from the service box. I have plenty of 12/2 romex around but wasn't sure what would be appropriate for a 50 amp line.

TIA


P.S.
I now have a 225LX and waiting for a PP50

At Home Depot today I bought 4-conductor 10 gauge, recommended by the salesperson. It was about $2.00 per foot.

jtybt
02-25-2010, 07:51 AM
$2.00 a ft! OUCH.

To complicate matters, I have a 10 Ga 25' extension cord putting total run at 50' so I presume 10 Ga Romex is much better.

What is the fourth wire for? Ground? I have a Leviton 50 amp dryer plug with no ground.

Steveg
02-25-2010, 12:52 PM
You should run 6 ga. wire for a 50 amp circuit.

sg

performance
02-25-2010, 04:39 PM
I agree, especially any distance from the panel box.

jtybt
02-26-2010, 01:25 AM
What would be the amp draw of the 225LX or the PP50...not being used at the same time.

The calculator link said 10 ga up to 50'. I measured the actual run, 24'.

Electrician at HD said the line and breaker should be matched to the unit being used.

Actually sounds to me that it's OK to used larger gauge wire as well as plugs and receptacles as long as the breaker matches the 'appliance' being used?????

performance
02-26-2010, 03:51 AM
Both show a max of 39 amps

jtybt
02-26-2010, 05:07 AM
OK Thanks.

I've been running the 225LX off my 220/12-2 20 amp breaker with no problem so upgrading to 10-2 40 amp should be OK! Very few of my actual welding is done over 125 amps and 2 minutes.

rinktumbody
02-26-2010, 05:43 AM
$2.00 a ft! OUCH.

To complicate matters, I have a 10 Ga 25' extension cord putting total run at 50' so I presume 10 Ga Romex is much better.

What is the fourth wire for? Ground? I have a Leviton 50 amp dryer plug with no ground.

One wire is ground (green), one is white (neutral), one is red (hot) and the other is black (hot). Good luck!

performance
02-26-2010, 06:29 AM
You could wire color for color and trim the red wire or other color wire, whatever color it may be. Just be sure to hook up the green ground wire to the middle round post. The 4th wire is considered a safety ground. If you will observe in some true NEMA welder type plug connections, there are actual wire colors printed on the plug itself, showing you what color to use. They all say black and white for the two hot legs and green for ground. I would not use the red if this is an extension type plug, just use the colors that are used in the welder if it terminates into a male plug and not directly into the panel box.

Steveg
02-26-2010, 12:07 PM
I don't want to be a spoiler, but, take a look at the IEC you will see the max fuse size for #10 non metallic sheathed cable the kind sold at HD is 30 AMPS.

sg

jtybt
03-01-2010, 04:02 AM
Turns out I already had 10/2 with a 20 amp breaker. Upgraded to 40 amp breaker and 50 amp plugs/receptacles.

shawn
03-02-2010, 02:20 PM
i really hope your not saying your gonna try and run 40 amps through 10 ga wire. if so i hope you have a good house insurance policy. for a 40 amp breaker you should be running atleast #8 and for a 50 you should be running a #6 otherwise you will be getting that wire red hot when pulling a max load and too many hot cold cycles will make the insulation melt off and crack and eventually creating a short in the walls or whereever the wires run which will in turn eventually burn your house down.

i've been an electrician for 17 years now and have seen people do this waay too many times for my own comfort and wonder why heir house burnt down or why their equipment burns up. the problem with running a smaller gauge wire for a larger circuit is it won't flow as well as the larger wire which in turn causes more resistance. the resistance in the wire makes the welder work harder to accomplish the same thing because it's not getting what it needs to do the job.

picture a 2" water line being used to fill a swimming pool now put a section of 1/2" at the end of that 2" line. your basically doing that same thing by using a wire that's too small for the load. your connection at the breaker are gonna heat up, the wire itself is gonna heat up, and your welder is gonna heat up because of all the effort it's putting into trying to get what it needs. somewhere something is gonna fail. most of the time it's the it's the appliance trying to be used but the other times it's either the wire or the breaker and either 1 of those are very adept at starting a fire

shawn
03-02-2010, 02:24 PM
oh and by the way read the sentence at the top of the page of that link. he tells you his calculations aren't up to code and to reference the nec to make sure he's right

jtybt
03-03-2010, 03:09 AM
What would be the amp draw of the 225 with a base amp setting of 125 amps?

Most of my base settings are between 55 and 90 amps welding .060" or thinner SS with foot peddle.

Even welding thick aluminum set at 127 amps with a 20 amp breaker, I didn't pop the breaker. That's the main reason I'd like to know what the actual amp draw is at different base settings. I figure there's a formula somewhere.

shawn
03-03-2010, 03:52 AM
look at the nameplate on the unit that'll tell you what the max draw is on the unit. just because it's a cut 50 doesn't mean it'll pull 50 amps from your panel.

Rodsmachineshop
03-03-2010, 04:15 PM
yes dosnt pay to cut corners and not use the wire size you should use . My machine shop is wired in number 6 wire when setting up my machine shop ended up using about 3 x 500 ft rolls of number 6 , most my machine are 3 phase so you end up with a extra wire to run . plus all the emt conduite and breakers and sub boxs. I think with everthing doing it with my dad was like 1500.00 . but know i am up to code and not over stressing the wiring.

jtybt
03-03-2010, 06:50 PM
OK, so I pulled the 40 amp breaker and will go to a 30 amp breaker with 10AWG.

At least that way it will pop before things get hot. I might even go back to 20 amp breaker. It was working fine with the 20 amp breaker. Mainly I wanted to go from a 20 amp plug to a 50 amp plug cuz that's what I've found at most shops/yards that I might have some work.

Ray
03-03-2010, 10:11 PM
Sorry I steped out. If Shawn is an electrician I'd beleve him over anybody including me.
Here's another link , this one also acounts for stranded wire.
If you go buy this calculator 8GA solid core will carry 44.6 amps over 25', personaly I go for overkill I ran 4GA across the shop for a 50amp circut for my compressor, it does seem funny the 250EX would have a 12GA cord on it though.

http://www.geocities.com/CapeCanaveral/Lab/9643/awg.htm

everlastsupport
03-03-2010, 11:44 PM
A 50 amp cutter will pull under but close to 30AMP when you power it and will run on 30amps without a problem. The output voltage is not 220 volts at the torch, it is rectified and stepped down. There are details on the back of the unit, should have an Max I (max current)

On the gauge of the wire, there are plenty of tables on the internet. But the length does affect the gauge as well. Long run, lower gauge.

It is always better to be safe than sorry. Though I know things are tight on most right now. If you are in doubt, hire a professional electrician.

Steveg
03-04-2010, 01:51 AM
Current capacity of a wire depends on conductor size and the type insulation on the conductor. IE TW, THW,THHN, etc check the code.

sg

jakeru
07-29-2010, 05:38 PM
If you look at the actual size of the wire feeding into the back of your unit, you may be under-whelmed, or surprised. I think my Super200P has something like 12 gauge (or maybe it was even 14 gauge) wiring in the main power cabling that feeds it, and inside the unit. And after the power switch, it all goes through a quick connect spade terminal into a printed circuit board trace, too!

However, it seems to be working just fine. I have tripped my 30 amp breaker using the plasma before, but there has never been any sign of anything going wrong with overheating or undersized wiring inside the unit. Also the arc seems to be rock solid consistent. I think inverter machines like everlasts are able to handle varying or fluxuating voltages much better than competing transformer machines do.

mp006ltk
12-09-2010, 06:00 PM
The breaker is there to protect the wiring int he walls, and not he equipement attached to it. Length of run is important, but a rule of thumb is 6 awg for 50 amp, 8 for 40. If you put a 50 amp receptacle on the wall run the apropriate cable and breaker. The same thing goes for 40 and 30. If you ever sell your house/shop you will most likely have bigger things to worry about than to cap off the receptacle, and someone is likely to plug a dryer into an outlet wired by a 10 awg cable. Thats when lawyers get involved.

Oh and if you're in Chicago, the code is crazy, so hire someone. Residential in that area requires conduit. They're a little extreme, becasue of the union influence and the fact the entire city has allready burned to the ground once.

TAPnTX
02-10-2011, 03:50 AM
I know this is an old thread, but was looking for an Extension cord for my Powertig 250 EX.

There are a few options that are not to expensive and should meet Code requirements.

RV's use a 30 AMP (8 ga.) and 50 AMP (6 ga.) extension cords to hook up when parked where there is power.

The other is Hobart and some others make a Welder extension cord for 50 amp 230 volt welders or plasma cutters.

Both are reasonably priced and readily available.

Listen to Shawn!!!


Todd

bigjoeinkg
04-15-2011, 10:42 PM
Checked the price today for the 6AWG/2. Lowes had the cheapest price. HD was over $3/ft. I will be running the #6 to my 50A outlet. Copper prices are getting up. Who would thought that copper would follow gold and silver as a precious metal.

Tritium
04-16-2011, 12:34 AM
China is thinking about backing their currency with copper. If that happens watch out, old pennies (the solid copper ones) will be like dimes or better. I had a shop fire 10 years ago and finally am getting around to cleanup of the copper (welders, wiring, cable etc.) I took it to the metals recyclers Tuesday and got $344 for 106 lbs of badly burned copper.:D I just finished putting in a new 50A circuit for my Lincoln Tombstone AC welder yesterday. Luckily I had just enough #6 left over from a few years back at 50 cents a foot.

Thurmond

bigjoeinkg
04-16-2011, 01:57 AM
Went to an estate auction last week. Picked up about 200 ft of 14/2, 75 ft of 12/2, and 50 ft of 10/2. New 6-50 outlets, 100A sub panel with breakers, conduit, rough in boxes and lot of other goodies. Paid $15 for the lot. Had a good 1HP and 1/3 HP motor to boot. Bad thing is, I have to go buy the 6AWG wire.

Tritium
04-16-2011, 03:38 AM
Went to an estate auction last week. Picked up about 200 ft of 14/2, 75 ft of 12/2, and 50 ft of 10/2. New 6-50 outlets, 100A sub panel with breakers, conduit, rough in boxes and lot of other goodies. Paid $15 for the lot. Had a good 1HP and 1/3 HP motor to boot. Bad thing is, I have to go buy the 6AWG wire.

Score!! What a deal!

Thurmond

ogorir
05-31-2011, 11:38 PM
+1 on 6ga for in-wall wiring for 50a plug. I went a bit cheap-### with my extension cord @ 8ga SEOOW seoprene cable. still cost me $120 after tax for 50 feet.


I should also add that length doesn't affect the current carrying capacity of a wire. it DOES affect the voltage drop, though, which is why you need to bump up to the next bigger gauge for long runs. the actual current carrying capacity is determined by how well the cable can dissipate heat and the insulation on the wire. for instance, the old school knob and tube wiring can carry a lot more amperage through the same gauge conductors because the wire isn't insulated and it's stood off in the air similar to a transmission line. and to the guy who said that pulling 50a through 10ga will make it 'red hot' is exaggerating to make a point. not a good idea for sure, but definitely not near 800 degrees.