power cord

[travis]

i just got given a 35 ft long 50amp ext cord once used on a rv it is 6/3 with a 8 gage ground this will give me the movement i need in my work area

[Mr120]

That's a pretty nice gift. Nice thick cord like that won't have very much voltage lost to it at all.

[Tanh]

You have some very nice friends Travis. A cable like that is over a bill here if you buy new. 35' might just be long enough to reach anywhere in a small shop/garage. What kind of connectors does it have on it?

[travis]

one end has a male 4 plug other end is loose

[Tanh]

4 plugs? It might be a nema 14-50p. Does it look like this?



If it does you are in luck cus that's a dual voltage plug. You can run 240v and 120v with that cord. Great for having a grinder or saw handy where your welding.

[MuttonHawg]

4 plugs? It might be a nema 14-50p. Does it look like this?



If it does you are in luck cus that's a dual voltage plug. You can run 240v and 120v with that cord. Great for having a grinder or saw handy where your welding.

That's exactly my plan for an eventual welding cart - provide 240V and 120V power on the cart itself (with a NEMA 6-50 receptacle for the welder and standard 20A receptacles for whatever else), with a hard mounted cord from the card that will plug into the wall. I'll probably end up buying an RV cord off Amazon and chopping off the receptacle end and just using the plug and maybe 25' of cord to reach anywhere in my garage or driveway.

[youngnstudly]

Cool score! It would be sweet if that was dual voltage!

Looks like I need to find some new friends...Or find friends in the first place!

[travis]

male plug looks like that yes and i have a black red and white wire along with a green ground wire
ok so how do i run dual voltage ? i was thinking that today it would be nice to have a 110 and 220 all togather

[MuttonHawg]

Well, I plan to build 2 metal boxes on my cart that are the same size as a standard galvanized electrical junction box that you'd mount to a wall stud. In one of these boxes, I"ll mount a NEMA 6-50 outlet, and in the other I'll mount a standard 120V outlet, then put standard cover plates on them. Basically, it'll be just like installing a couple of wall outlets, but it'll be on the cart. As for the wiring, I'll run the black, red, and green wires of the cord to the NEMA 6-50 outlet. I'll also run the black and white (neutral) wires, plus the green for ground, over to the 120V outlet/box. Then, when the 4-conductor plug is plugged into the wall, I can plug in a welder and/or any 120V tool to the cart, and I'll be mobile.

I'd recommend discussing this with an electrician before you actually wire anything up yourself - it's always a good practice to get an expert to check on your work when with high voltage/current like this! (and yes, I'm making a basic CYA statement)

[Rambozo]

male plug looks like that yes and i have a black red and white wire along with a green ground wire
ok so how do i run dual voltage ? i was thinking that today it would be nice to have a 110 and 220 all togather

The big problem with that is that you will have 50 amps of 120V! Not the best thing to run small power tools on because something like a locked up motor will probably not pop the breaker, and set fire to it instead. The best thing would be to add a smaller circuit breaker to your cart to provide better protection for 120V.

To be blunt, if you have to ask about it, it's probably not something you should be doing. If you do plan to go ahead, please at least use a power strip with a circuit breaker on your cart.

BTW, that is not your typical RV plug, but a standard 120/240 plug. You can get receptacles for that at Home Depot. Most RV plugs use the NEMA TT-30.

[MuttonHawg]

The big problem with that is that you will have 50 amps of 120V! Not the best thing to run small power tools on because something like a locked up motor will probably not pop the breaker, and set fire to it instead. The best thing would be to add a smaller circuit breaker to your cart to provide better protection for 120V.

To be blunt, if you have to ask about it, it's probably not something you should be doing. If you do plan to go ahead, please at least use a power strip with a circuit breaker on your cart.

BTW, that is not your typical RV plug, but a standard 120/240 plug. You can get receptacles for that at Home Depot. Most RV plugs use the NEMA TT-30.

Fair enough. I hadn't researched the case of whether or not an over-current on just one of the 120V legs would trip the 240V breaker. Electrically providing the right power is one thing - doing it safely is another. If I have to mount a little pony panel on my cart, it's a non-starter and I'm not going to bother doing it. I'm definitely going to consult with a licensed electrician before wiring up my cart, though.

I wonder if electric stoves and clothes dryers, which use a 4-conductor plug to provide 240V for the main heating element and 120V for the control electronics protect the condition you describe? Wondering if they have internal fuses on the 120V circuits, or if the current they'd pull, even in the even of a failure, would be small enough to not cause a problem. I could certainly see how a little electronic circuit board might not pull the same current as a jammed motor.

[MuttonHawg]

Upon further research, a short on EITHER hot leg of a 2P breaker would trip the entire breaker (both sides). However, it would still take 50A to do that, which would NOT be safe to run through all the 120V wiring (which would only be rated to about 20A), including the 120V outlet, the tool's power cord, and the tool itself.

So yes - any 120V circuits on the cart should absolutely have some sort of protection at a much lower current (20A). I don't think a circuit breaker on a power strip would be enough, unless perhaps the power strip was hard wired instead of plugged into the 120V outlet. It would probably be easiest to just run 2 cords from the cart to the wall - one for 240V and one for 120V. I got a little ahead of myself - thanks for bringing me back into line!

[Rambozo]

Fair enough. I hadn't researched the case of whether or not an over-current on just one of the 120V legs would trip the 240V breaker. Electrically providing the right power is one thing - doing it safely is another. If I have to mount a little pony panel on my cart, it's a non-starter and I'm not going to bother doing it. I'm definitely going to consult with a licensed electrician before wiring up my cart, though.

I wonder if electric stoves and clothes dryers, which use a 4-conductor plug to provide 240V for the main heating element and 120V for the control electronics protect the condition you describe? Wondering if they have internal fuses on the 120V circuits, or if the current they'd pull, even in the even of a failure, would be small enough to not cause a problem. I could certainly see how a little electronic circuit board might not pull the same current as a jammed motor.

Yes, most large appliances provide protection for each load inside. Usually with fuses soldered on the circuit boards. As you found out, over current on either leg will trip both of them. In fact a lot of two pole breakers are just two single pole breakers with the handles pinned together. Magnetic starters are the same, but use a different method to trip all lines, even if there is only a problem on one.

A sub panel on the cart would be the right way, so I can understand that you might want to pass on that. Two cords also means that if you are just using 120V you won't need to haul out that heavy cable. I have 100 feet of 6/4 on my welder and I dread coiling or uncoiling that monster. But check with an electrician and go over your options. You might like just the one cable and if you do it safely there is no problem. The cost will be much the same either way.

[sportbike]

How about just wiring in a power strip with a built in 20A breaker on it?

[travis]

so theres no way to wire a 11o off the rv cord ?

[Rambozo]

How about just wiring in a power strip with a built in 20A breaker on it?

That's probably what I would do for myself.

[Rambozo]

so theres no way to wire a 11o off the rv cord ?

There is, but to do it safely requires that you provide some lower amp protection for the 20A outlets. If you are at all unsure, get an electrician to wire it up for you.

[ShaneJackson]

To be blunt, if you have to ask about it, it's probably not something you should be doing. If you do plan to go ahead, please at least use a power strip with a circuit breaker on your cart.

Isnt that the proper way to learn how to do something? Ask first and follow directions? Sure as hell beats guess and ask how to fix later.

[Tanh]

To cover everybody's bottom side, I'll say consult with a qualified electrician first. Over here usually only the stove has dual voltage cus it has to run lights and electronics on 120v. Most dryers and washers use the Nema 6-30 with few exceptions.

This is what I did on my stove receptacle. Code here says you have to have at least a single gang wall mounted box for any junction and any 240v line should have only 1 receptacle/appliance on it. That might mean that if you don't have that type plug near your garage, you'll probably have to run cable. If you do then it's all good.

The 240v is gotten from the red and black cables. They are both 120v with 180 degree phase shift. Neutral is not used on 240v and ground is for safety. The 120v should be taken from the red and white (neutral) wires. I say red cus it's convention to keep the same phase as the rest of the 120v in your house and that's usually the red wire. So a 20amp breaker should be put on the red wire going to the 120v receptacle. This means you should have 3 boxes. One for 240v, another for the inline fuse/breaker and one for the 120v. And since you'll be using the welder in a designated "damp" space (garage or outside) you'll need a gcfi for the 120v and the 240v Should have weather sealing. Here's a diagram that may help.




Just to make sure you know, it's not good practice to ground the neutral as a shortcut. If there was a case of a hot short the neutral would be live and so would any ground that on your equipment. Ouch! Hope this helps.

[Rambozo]

The 120v should be taken from the red and white (neutral) wires. I say red cus it's convention to keep the same phase as the rest of the 120v in your house and that's usually the red wire.

BTW 120V circuits in a house are split evenly over both hot legs.