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Joined: Oct 2017
Posts: 6
New Member
Hello everyone. Hope all is well, It's nice to be here.

I built a cart for my Mig, Tig, Tig-Water Cooler, Torch Set, Plasma Cutter & Shielding tanks for welders & Torches.

I built a cart for my Stick, Mig, Tig, Plasma & water cooler.
I got ahold of some old 1930's steel cartwheels. I decided to Fab up a two-story cart with a roof and side walls & tool drawers. Anyway, I was hoping to Power the cart. I have the outlets and wire needed for the cart its self. My first plan was to run at least 100 amps to a subpanel on the cart via 3 pole cord. This way I could power a welder and plasma at the same time. I was thinking of adding an additional Nema 6-50 in the case it is needed. I also wanted to have 4 Nema 5-15 outlets for tooling. So the cart would have 4 Nema 6-50 outlets and 4 NEMA 5-15 outlets.
I was thinking about attaching a 12 space 24 circuit subpanel right two the cart. However, finding a 100 + amp portable cord @ 40' is proving to be a challenge and very expensive. I also don't feel its the best plan for my goals.

I started thinking I will only be powering one of the units at one time. Max input/rush amp rating for units are as follows (Mig = 48A)
(Tig = 41A)
(WC = 1.1A)
(Plasma= 40A)
So I started to think I can put a 125A subpanel run a 60-70amp cord from the 14-50 wall outlet to the subpanel Drop 3-40 amp breakers in the subpanel and 1- 50amp breaker & 2-20amp for the 5-15outlets using them as on/off switch at the same time. making sure to only run one unit at a time.

If I'm looking at this wrong or anyone has a good idea I'm willing to listen.
My goal is to not have to run 4 + cords running from my cart. I also don't want to have to unplug one device and plug another in to change from one to the other. Running one cord from the cart to a wall outlet.
The only time I can see running more then one is if my welder or plasma is still on and I pick up a grinder and start working. However, the welder or plasma will not be drawing many amps at that time. It will be a lot easier to flip a switch then unplug and plug in every couple of min. I have pics of the cart build as it is still in progress. Framing is complete starting to find the locations for outlets now.

Looking for some advice on accomplishing my goal in this build. Also looking to make sure I'm not building a death trap. I have electrical experience especially the motherboard and computer repair field. I ran 90% of the electrical in my first home and of course have a good basic understanding of electricity. I have a habit of looking at it like water. Water in water out. However, I have never tried anything like this before. I'm well aware of the fact I'm not a professional Electrician. clap
Possible final material list: Subject to change!

Wall outlet: Nema 14-50R 3-Pole Qty= 1

Power cord: 4/4 SOOW SO Portable Power Cord 3-pole 60 amp 2-pole 70 amp rating. QTY= 1

Subpanel: attached to the cart, 125-Amp 12-Space 24-Circuit BR Main-Lug Outdoor. removing green lugs. QTY= 1

Breakers: 40 Amp 2 in. Double Pole Qty= 3
Breakers: 50-Amp 2 in. Double Pole Qty= 1
Breakers: 20-Amp 1 in. Single Pole Qty= 2

Outlets: on Cart, Nema 6-50 Qty= 4 Nema 5-15 Qty= 4 total Qty= 8

Wire: Sub-P to Outlets: 10-AWG Stranded CU THHN Wire, run length= 2' - 3' to each outlet.

Safty Switch: On Cart, General Electric TGN3321 Safty Switch Qty= 1

Conduit: To outlets on the cart, 1/2 in. EMT Conduit
looking for pointers and/or mistakes I made in the designing of the powering of this build. Thank you!

Joined: Oct 2017
Posts: 6
New Member
So, I was thinking last night. Since I'll be going with NEMA 6-50R outlets Mostly because all my welders are factory NEMA 6-50 plugs. I was thinking I could get away with running a 2/3 SOOW SO Portable Outdoor 600 V Flexible Cord instead of the 4-4 SOOW SO Portable Cord.

The (2 AWG 3 Conductor cord) is around the same price as the (4 AWG W Conductor Cord) I was originally going with.
For some reason, I just thought it might add some safety to the build if I ran 2 hots-Neutral & Gound to the subpanel instead of 2 hots and Ground.

Then I started thinking Wait if I'm running 4 NEMA 5-15 The Neutral will be needed.
I sometimes over think things. However, with electricity I learned at a young age you can't be too careful.

I'm I correct in this I can't get away with the 2 Pole 3 wire cord?
Will I have to stay with the 3 pole 4 wire cord?

I also wanted to clear something up.
The maintenance DEPT at my place of employment is trying to tell me I need to bond the Neutral and ground in the Subpanel.
I have installed a few subpanels in my day.
My understanding has always been when it comes to the Subpanel you don't bond neutral to earth ground. One if you neutral and ground are bonded the Ground is flowing current. as far as I'm aware ground should never be used for current. It will also cause the box that the ground is bonded to becomes live. if you touch the box and a ground of some sort it will light you up. This is how I was trained. However.

The Maint department manager is trying to tell me otherwise. It makes no sense to me at all. however, he does have me second guessing myself.
Am I wanting to confirm I am right in my thinking?

Joined: Jul 2004
Posts: 9,928
Likes: 34
The first thing you have to do is get a better handle on your expected load. You do not to build this to run everything if you are only running them one at a time,. Then go 125% of the biggest load.
There are also rules that allow smaller conductors for welders but you probably should get some engineering advice that may be beyond the score of this group.
You are right about separating the neutral and ground. You also do need 4 wire cord.

Greg Fretwell
Joined: Jan 2007
Posts: 36
Unless its a generator, at your Panelboard, NEC ARTICLE 551.45 - instructs us to insulate the neutral feeder from the enclosure, just like any other sub-panel.

Generators, and Telephone D-Marks are the other noodles, which bond EGC's to Neutrals.

Roger Ramjet
Joined: Oct 2017
Posts: 6
New Member
Thanks for confirming.
As I said It has always been common practice to insulate the neutral from the enclosure on a subpanel. I believe in the heated discussion while trying to convince him he was wrong and why he was wrong. I started second guessing the basics. It has been a few years since I've studied up on AC current. I'm cautious with electricity, mistakes are easy to make. I have unloaded 100's of capacitors in my day for a replacement. just the other day I missed one and got a bite. Thanks again for confirming.

Joined: Oct 2017
Posts: 6
New Member
Thanks gfretwell!

My expected load was listed above in original post. Mig at 48-amp will the largest load. I'm not so good with word. My apologies if I things were getting confusing.

I'm well aware of the load expection.. 125% of my largest load has me at 60amp. worst case one person welding one grinding with a 15-Amp grinder. If welder was cranked up with would be 125% 78.75-Amp. However, I don't deal with the real heavy steels. The welder will maybe see full load once or twice in its lifetime at my shop.

I guess I was just looking for confirmation that I was going about this correctly not missing anything in my layout.

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