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Main box feeding 220v and 110v brearker box off a 50am breaker?

12K views 30 replies 7 participants last post by  uvamosk 
#1 ·
Hello Everyone,
I just purchased a 220v welder as I am starting to get more into welding and have completed my welding class.

Buying a 220v welder I knew I didn't have a 220v supply in my garage so I started reading into it but I have a few questions I need to iron out before I start on this project.

Before I start: I am going to do all the wiring and get as much ready as I can. Then I am going to call in a electrician to check it all and give me the OK and to hook it up to the main panel.


Here is what I'm thinking:
I have room to put in a Double Pole 50amp breaker in my main box in the house.

I was going to run 10/3 4wire cable in PVC tubing underground.

I was going to use a Disconnect and hook up a breaker box in the garage.

I was going to see if I can find a 50amp main breaker for the box and then run 220v with 30amp circuit for the welder and 2 110v 20amp circuit for power tools.
Also of course this box would have grounding rods hooked up.

I am going to make all connections properly and using the right boxes and everything.. So don't think this is going to be a hack job.

I Just wanted to make sure this was the correct train of thought. The garage will see light use mostly just welding. I'm not running a shop or anything where I have to worry about a huge pull on the breaker. Just figured a 50amp breaker would be good enough to supply everything. Might also run another 220v one day.
 
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#2 ·
You can't use 10-3 for 50 amps, probably more like #6 wire
Is the garage attached, detached? - you say underground so I think detached
With a sub panel in a detached structure you will need grounding rods
You need to run 4 wires & that will be a 240v sub
Grounds & neutrals on seperate buss, neutral buss not grounded to the case
 
#3 ·
Yeah I figured I would have something wrong lol thats why I was checking.

I figured it would have to be bigger than 10 gauge but I wanted to check.

Other than that it sounds like I'm on the right path.
I will be using grounding rods as it is a detached and I'll be running #6 also.
All my hook-up's also seem to be in the right order.

Other than the #6 everything I described should be good to go?
 
#5 ·
I'm looking at probably less than 100 feet I have to measure tomorrow for sure. I'm pretty sure it will be under 100 feet. You know how much #6 goes for per foot?

Back when I was just going to run a 10/3 220v to the garage I was looking at 4 wire cable that had a outdoor coating. I was going to use it and bury it in PVC conduit.

It his advised and if so does #6 come in that same setup.
 
#8 ·
The price will varies depending if you use the UF route or THHN/THWN in conduit so look around.

Most big box store do sell roll of conductors or cable they typically come in 25 , 50 ,100, 250 , 500 even 1000 foots spools

So you can get one close to what you need it. somecase you may want to order extra you have to remember the burial depth that can really screw up the count of mesure if not watching it carefully with it.

Merci,Marc
 
#9 ·
Hold on a minute! Welders are addressed as special equipment in the NEC and are treated differently than other equipment or appliances. For one a welder is duty rated. So it does not need to be protected the same as continuous duty equipment or appliances.

You have not told us whats on the welder nameplate. We need that to tell you what size breaker and what size wire. In some instances a breaker much larger than would normally be allowed would be allowed. Welders are one of them. What does the manufacturer say. They usually provide breaker and wire sizes for their welders?

I agree with Dave regarding the sub panel. This is no time to skimp. You must by code install at minimum a 60 amp panel in the unattached structure. So install a 60 amp feeder to a sub panel in the building. Use 1" conduit and four seperate lengths of THHN/THWH wire. 2-Blacks/1 white/1 green. (#6). Two ground rods connected to grounding strip in the sub panel. I would use bare #6 for the ground rods. Keep them next to each other. You need a main breaker panel or a disconnect.

Note: Using the search function above, search "sub panel" or "wire garage" or "run wire to garage". Keywords like that will get you more information than you can read. Concentrate on your feeder and sub panel first. Then get all the information on the welder. We will work on the welder, once you get the sub installed and ready.
 
#11 ·
Hold on a minute! Welders are addressed as special equipment in the NEC and are treated differently than other equipment or appliances. For one a welder is duty rated. So it does not need to be protected the same as continuous duty equipment or appliances.

You have not told us whats on the welder nameplate. We need that to tell you what size breaker and what size wire. In some instances a breaker much larger than would normally be allowed would be allowed. Welders are one of them. What does the manufacturer say. They usually provide breaker and wire sizes for their welders?
IMO this only applies if you are wiring the welder in a commercial setting where there is control over the receptacle and how it is used, or if the welder is hard wired with a disconnect.

If this will simply be a receptacle for a plug-in welder in a residence I personally don't feel the special stipulations in Art.630 (Welders) should be used.
 
#12 ·
How many spaces in the 50 amp main breaker panel? You could use 50 amp, if it provides enough room for the breakers you are going to use plus a few spares? The welder will take two slots. I would think a 60 amp panel would be common. Maybe not. Check another supply house.

You could use a 100 amp main breaker panel (very inexpensive) and and feed it with a 60 amp feeder. Or feed it with a 100 amp feeder. It all depends on what you plan to do in this building. If you are going to have a few appliances, some tools, the welder, 100 amp seems like it would be the way to go. Then you have all the room you need, plus room to add more later.

Since the welder calls for a 30 amp breaker you would normally use #10 wire. You may be able to use smaller wire. Depending on the amp rating of the welder.
 
#15 ·
I got ya, so using the 100amp panel it serves as the disconnect. I was at lowes the had a DP60amp in thick but I needed thin. I'll check HD. So I should still use #6 wire right. I was looking for some at lowes guy there said I could use 6/3 would that be advised as this is just a garage power source for light use.

On a side note if I bring in a 220 and feed a subpanel then run some 110v plugs will running a tool while welding lead to any issues with the welder? Since they share the same feeder breaker from my main box.
Just asking as I want the welder to preform at it's best. I could just run a 220v straight to the welder if I had to as there is 110v in the garage now.
 
#17 ·
I got ya, so using the 100amp panel it serves as the disconnect. I was at lowes the had a DP60amp in thick but I needed thin. I'll check HD. So I should still use #6 wire right. I was looking for some at lowes guy there said I could use 6/3 would that be advised as this is just a garage power source for light use.

QUOTE]

What do you mean a thin breaker?
Most 60 amp 3 pole breakers take up 2 spaces.
Ge can take up one space, but it must be positioned right to get 220 v
6/3 is fine as long as it is UF.
Induvidual wiring in conduit is best.
 
#16 ·
Make sure the 6-3 is rated to be used underground - wet location
It seems HD employees keep recommending wire that is not rated for the intended use
What kind of panel is your main panel?
I have Square D - so for me thin = 120v, thick = 240v
thin with 2 handles = tandem breaker & will not give you (me) 240v

You can't have 2 feeds like that to the garage
In order to have the 240v & 120v you must install a sub panel
 
#18 ·
Well,
My current setup that was here when I moved in has a 40amp taking up 2 thick spots which goes to the stove. The other 220v going to dryer and ETC are all double POLE Thin breakers.

Now don't freak out when you see my box it looks worse than what it is :eek:. I have about 4 unused breakers in there that go to nothing, go figure.

So if those things using 220v that are running off a Double Pole thin breaker then I should be ok to use the same breaker for my 220v running to my garage?

I had this house inspected when I bought it and the inspector had open the box and looked in it. Other than the Dryer plug being mounted in the wrong place everything tested fine and was good on the wiring side he said.
 

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#23 ·
Thanks for all your help guys think I got every thing to get this going.
I'll look at the dp think breakers and see how they hook up.

One last question if I run 6/3 can I use PVC conduit?

Woah for a minuite please did you say conduit ? and 6/3 UF ? both at once ??
If full length of conduit no you can not do that but if for few feet for protection yes it will be ok but really if you going to run full conduit then you have to use the THHN/THWN conductors

Merci,Marc
 
#25 ·
Well,
I came across 8/3 UF for .40 cents a foot at HD... :eek: on clearance.
So I double checked everything and decided to just go with a 40 Amp breaker in my main and a 40 amp in my sub panel.

The welder is rated at 30amps max settings which it will never be used for and I'll have only one light hooked up. I called a Electrician and they verified that I can bury 8/3 UF in PVC conduit with out any issues and it is with in code. I purchased everything today and cleaned up my main box to get ready for the DP 40amp breaker.

once I have everything ran the electrician agreed to come out and check my work before I put power to it all and they said they would drive my grounding rods and install hook them up also.

Our ground out here is filled with huge chunks of rocks and since it mountain terrain so I figured why not pay them to deal with that mess :thumbup:.


Anyway, .40$ a foot was insane and since I was buying most the roll he just gave me the whole 90foot roll for 17$ :)
 
#29 ·
Let me expand little more on Dave's comment if he don't mind :whistling2:


Ok what we do with cable espcally with NM or UF cables we do count by the wide part of the cable and to order to get in 40% fill we do have chart that tell us and right now with your 8-3W/G UF you will need 1.5 inch conduit instead of 1.25 conduit due the fill sizing.

I am kinda suprised they will allowed like that unless that the local code do allow it for good reason for here we don't do that way.

Merci,

Marc
 
#31 ·
I didn't look up any info on the conduit size. So that was my honest mistake. I'll get 1.5".
I'll take back what I have now. I understand the reasoning behind having 1.5 and thanks for the explanation.

I didn't know I should try to keep it under 40% fill rate on the conduit.
 
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