10-50 to L6-30

First, let me say sorry for the stupid question. Second, let me add a disclaimer that I'm not an electrician and I know I can kill myself with my ignorance. Third, I don't believe that electrical stuff is some form of witchcraft that I must outsource to wizards. I just need some simple direction, and with that direction, I think I can do it safely if I do it right.

I'm making a 10-50P / L6-30R adapter so I can charge my LEAF on an old 240V electric stove outlet in a house that I'm rehabbing- 10-50 has two hots and one neutral (labeled X, Y, W), while L6-30 has two hots and one ground (labeled X, Y, G)- why the discrepancy? I know ground and neutral are close relatives, but I'll be wiring the ground of one side to the neutral of the other side, and that just makes me feel all dirty inside.

My guess is 10-50 is an old standard and having a dedicated ground was uncommon. Is that correct?

Correct. The newer standards with dedicated grounds are the 14-30/14-50.

Have you thought about changing the cable to the stove to one that uses a 14-50 receptacle, i.e. have a proper equipment ground separate from the neutral that goes back to the breaker panel, and using perhaps NM 6/3 cable? Then you need not feel "dirty" and you won't have to worry about the possibility of a "broken neutral" connection to your stove causing your stove's frame to become electrically hot (because currently the neutral is connected to the frame).

The house is empty right now, so no stove is in place. It's also got gas hookup available, so I may not even be using an electric stove. I'm not sure if the wiring used has a fourth ground wire, but it wouldn't surprise me if it didn't. The house was built in 1955 and has had no upgrades (or even repairs) since the early 90's- so none of the outlets are grounded properly (some have been upgraded to 3-prong outlets, but the ground is bootlegged to neutral).

I'm only rehabbing the house to the point of meeting city code so I can get a certificate of occupancy (it was a foreclosure, and put into the vacant and abandoned building program, so no occupancy until I dump money into it). Upgrades and repairs beyond city code violations aren't budgeted, and ungrounded outlets are OK per city inspectors, so no 14-50 receptacle in the near future. I don't make a lot of money, so I'll be roughing it for the next year or two...

kubel said:

I'm not sure if the wiring used has a fourth ground wire, but it wouldn't surprise me if it didn't.

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So, you could replace the stove receptacle with a 6-50 receptacle, and "move" the former neutral conductor from the neutral bar to the ground bar. I say "move", because if the ungrounded stove receptacle was installed properly according to the code at the time, its wiring came directly from the main service panel, where the neutral and ground bars are the same, so nothing needs moving on the supply end.

Cheers, Wayne

Correct me if I'm wrong, but the proper wiring on the service side would be two hots to the breaker, 1 neutral and 1 ground to the ground bar. If I use the current wiring and it's 2 hots and 1 neutral, and I move neutral to ground at the panel, wouldn't I be in the same boat as I am now with a 10-50 if there's ever a fault?

Edit: Also, I wouldn't be able to use this outlet as an electric range if I did that, would I? As I understand it, electric ranges get 120V by using one hot to neutral, and 240V with both hots, right?

kubel: What you wrote seems ok to me.

I think running a separate 6 AWG green ground wire along the original cable (if accessible) may be an acceptable method to provide a ground at minimal cost to that circuit.

I have heard that the EVSEs are very sensitive about a proper ground. Will they even work if you connect it to an old stove or dryer outlet, where the neutral and ground are together?

Graycenphil: Since an outlet's neutral wire is normally properly connected to the outlet's ground wire at the breaker panel, I would say yes -- but DON'T connect the neutral terminal to the ground terminal at other outlets (and preferably at no outlets), ground the outlet by a separate ground wire.

As an example, if a single 2-wire cable circuit consisting of only a hot wire and a neutral wire and, say, 16 duplex receptacles were re-wired with three prong receptacles where each ground prong was connected to its neutral prong. If a "broken neutral" condition occurred, say, in one of receptacles (so that none of the subsequent receptacle's neutral is connected back to the ground bus of the breaker panel), then if any of the subsequent receptacles has a device that is "on" this causes the neutral AND GROUND to become electrically hot together with any device's metal exterior frame -- setting up a real potential for electric shock should someone touch that energized frame and something else that is grounded like a sink typically is in a bathroom (since it is connected to the usually grounded water pipes).

As long as that 10-50 is dedicated and wired properly, you can simply repurpose the neutral as a ground in your adapter.

Thanks. Makes sense.

MikeD said:

Graycenphil: Since an outlet's neutral wire is normally properly connected to the outlet's ground wire at the breaker panel

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I believe you mean they are connected at the main breaker panel, the service entrance; at subpanels they are kept separate.

Cheers, Wayne

kubel: Thinking about your original post some more it occurs to me:
1) Besides the adapter (most(all?) EVSE instructions say "Don't use"),
2) you probably need an extension cord (most(all?) EVSE instructions say "Don't use"), and
3) I think implied safe use strongly suggests changing the circuit breaker for your 10-50 receptacle circuit from 50a to 30a for your intended EVSE use, but since the outlet may be used in the future with a stove requiring a 50a breaker, the situation seems very problematic. A better solution to me seems to change the 10-50 receptacle to a 6-30 receptacle so no adapter is needed, change the breaker from 50a to 30a, and ensure that the neutral wire goes directly back to the main breaker ground/neutral buses (if not (i.e. one or more sub-panels in between) or you're not sure, maybe using a competent electrician to help you out would be wisest).

If it were me doing this, I'd get a fused disconnect (about 15 bucks at an electrical supply house) put some 30 amp fuses in there. Get a surplus range cord hook that to the line end, and some 10 gauge SO cable (preferred because it is outdoor, stranded cable) connected to a L6-30R connected to the load end. Mount the fused disconnect solidly to the wall behind where the stove goes. When you are done rehabbing the house and are ready to install the stove take off the disconnect, unplug the cord and the stove will hide the holes.

My old buzzbox welder uses the old-fashioned range receptacle, wired as you say. When I first got my Schneider EVSE, I wired up a pigtail cord with the 3-prong plug to feed the thing. It worked fine. Legal? I don't know. Safe? Enough, IMO. You might want to change the breaker to a 40 amp if you're using a 30-amp EVSE, as that's what's recommended; there's probably a 50 amp breaker in the panel at present.

I have a 14-50 in my garage for my EVSE. It has no neutral and it is 40A. I put a label on it marking 240VAC and 40A. This is so someone would not expect their RV to work plugged into this socket since it can not supply 120VAC.

GlennD said:

I have a 14-50 in my garage for my EVSE. It has no neutral and it is 40A. I put a label on it marking 240VAC and 40A. This is so someone would not expect their RV to work plugged into this socket since it can not supply 120VAC.

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This can be a dangerous situation. You are far better off connecting the ground and neutral together at the outlet (still not recommended) than you are in leaving the neutral out altogether. I know you have a label and it's your own garage. If someone were try to plug a rv into it, and plugged a radio into an outlet on one side, and a air dryer into the other, it would fry the radio, Because of the way ohms law works.

GlennD: I am curious: what make of EVSE do you have for your Leaf that uses a 14-50? All the 30a or 40a "cord and plug" ones that I have read about seem to use the 6-50.

I guess the comment that I want to make is that it seems safest when the receptacle type can be relied upon to inform the user the circuit's voltage (including if both 120v/240v is provided), maximum amperage, whether it has an equipment ground, and even if it is GFCI protected.

johnrhansen said:

GlennD said:

I have a 14-50 in my garage for my EVSE. It has no neutral and it is 40A. I put a label on it marking 240VAC and 40A. This is so someone would not expect their RV to work plugged into this socket since it can not supply 120VAC.

Click to expand...

This can be a dangerous situation. You are far better off connecting the ground and neutral together at the outlet (still not recommended) than you are in leaving the neutral out altogether. I know you have a label and it's your own garage. If someone were try to plug a rv into it, and plugged a radio into an outlet on one side, and a air dryer into the other, it would fry the radio, Because of the way ohms law works.

Click to expand...

I agree a neutral wire would be better but I tried to buy 10 feet of white #8 at home depot. Needless to say after waiting for help over a half hour it did not happen.

GlennD said:

johnrhansen said:

GlennD said:

I have a 14-50 in my garage for my EVSE. It has no neutral and it is 40A. I put a label on it marking 240VAC and 40A. This is so someone would not expect their RV to work plugged into this socket since it can not supply 120VAC.

Click to expand...

This can be a dangerous situation. You are far better off connecting the ground and neutral together at the outlet (still not recommended) than you are in leaving the neutral out altogether. I know you have a label and it's your own garage. If someone were try to plug a rv into it, and plugged a radio into an outlet on one side, and a air dryer into the other, it would fry the radio, Because of the way ohms law works.

Click to expand...

I agree a neutral wire would be better but I tried to buy 10 feet of white #8 at home depot. Needless to say after waiting for help over a half hour it did not happen.

Click to expand...

Well I gave up on the Fullerton Home Depot and tried the Orange location. Still no one in the electrical dept. I had the paint person page for electrical help and ten minutes later help showed up. I wish Ganahl Lumber carried wire larger than #10 since they are friendly and helpful.