Any electricians in the house? Wiring your nema 14-50 gang plug

Any electricians in the house? Wiring your nema 14-50 gang plug

Any electricians in the house? Is it true you just wire the two "hot" terminals and the "green" ground leaving the "white" neutral alone? Would it be redundant to run both the green/ground and the white/neutral?

rdalcanto | August 20, 2013

NO, you need all 4. 2 hots, one ground, one neutral.

AlMc | August 20, 2013

rdalcanto is absolutely correct. If your wire it with three wires as you described it will not be code compliant and will carry with it lots of potential danger/liability.

If you do not feel comfortable wiring the outlet get a licensed electrician. If it is a short run it should run you $250-400..

If you have spent 100K on the car, do not short change your future
power supply costs.

nickjhowe | August 20, 2013

For answers, instructions, etc. etc. check out the "get the charging solution installed" section in the Model S delivery checklist and owners guide

jbunn | August 20, 2013

The hot wires by convention are usualy black and red. It does not matter which of the hot terminals they attach to on the outlet, but the white and ground wires must be hooked to their dedicated terminals. They will be clearly marked on the back of the outlet.

rswerts | August 20, 2013

If you have a reason to not use a neutral wire, you can install a NEMA 6-50R and get that adapter for your charging cord from Tesla.

SCOOBY | August 20, 2013

Will it work? Yes: the UMC does not require a neutral connection.

Is it to code? Maybe:see for an interesting debate between licensed electricians.

skymaster | August 20, 2013

I would install a 6-50. Adapter is 50 bucks from Tesla. Two hots and a ground...piece of cake. Make sure you use at least 6 gage wire.

travis2013 | August 20, 2013

Let me re-phrase, I am a contractor, I have a nema 14-50 gang plug, a 60 amp 240 breaker and 6 gauge wire. I DID run all four wires but was told by the Tesla "elect service tech" and know I read it somewhere on the Tesla sight not to use the "white or common lead" for the S Model,(I wish I could find it again.) Does anyone know for sure if you use the "common" lead? It's inside the box just waiting to be hooked up along with the "green ground."

SUN 2 DRV | August 20, 2013


Yes, you need to connect the neutral wire to the 14-50 receptacle. Since the wire is already there, what's the down side of just going ahead and connecting it?

The other comments you saw relate to the fact that Tesla doesn't actually use the neutral connection, but other appliances that might be connected to that 14-50 in the future could be significantly damaged and become become unsafe without the neutral connection.

Neutral should definitely be connected on a 14-50, and should be separate from the Ground connection.

SUN 2 DRV | August 20, 2013

schueppert: Thanks for the interesting link... I shudder to think that any licensed electrician would ever take such an unsafe short-cut

IMHO It's very clear that a standard outlet like the 14-50 MUST be wired in the standard way, which includes a neutral connection. To leave out the neutral connection just because some devices may not need it is very unwise because it leaves open the opportunity for other appliances with 14-50 plugs to be severely damaged, overheated, cause fires etc

Donato | August 20, 2013

Just looked at the "High Power Wall Connedtor" Installation Guide

For a 100 amp circuit it recomends two 3 gauge copper wires for L1 and L2 plus a 4 gauge wire for a ground. The neutral is not used. This is similar to a hot water tank installation. If aluminum wire is substatuted, probably 1 gauge will be required.

I don't think aluminum wire is allowed in some city codes; it has a reputation to start fires if not properly installed. Needs to be coated with an anti oxidation compound.

Vancouver, WA

SCOOBY | August 20, 2013

joehuber - I only scanned the material I linked to, but the gist seemed to be that any Level 2 EV charging installation must be dedicated, must be labeled for EV use only, and can't be used for any other purpose. You could argue that installing a neutral "just in case you want to use the outlet for something else" is actually encouraging people to break the code. To be clear, I come down on the side of believing it is best to install a neutral, but I don't think it is as clearcut as you suggest.

KWTESLA | August 20, 2013


Do it your self ! Do it right .
Here is how !
Black or Red are the hot wires which ultimately hook up to the breaker screws in your main panel.
Black or Red hook to the Y or X screws Brass colored screws on each side of the Nema 1450 R device.
White is the ground you have no neutral with 240 volt. Hook the White wire to the bottom straight blade having a Silver screw. Green hooks to the round pin on top. Ground has a green screw.
The green is a case ground or redundant ground wire. It hooks to to the side of the metal box or to green screw on your receptacle or wiring device. The green is also called an equipment ground used to protect you in the case of a broken ground wire. Back up system yes. Some brands do not use colored screws. The NEMA 14-50 device all look the same. holding the pin shaped hole on top ( the equipment ground) the hots are on the left and right . This leaves White wire at the bottom straight pin. Your Tesla mobile connector checks wiring for you when plugged in before you hook it to your car .
You can check it with a voltage meter before use as well you should have 120 volts from each of the two hots on each side to top round pin or the bottom straight pin . Zero from the bottom white to equipment ground .

shop | August 20, 2013

@schueppert, I don't think that argument applies, as a NEMA 14-50 is NOT a dedicated level 2 charging installation. It is a standard plug. And by code it must be wired in a standard manner. The Tesla UMC isn't even a dedicated level 2 charging installation, it is a device that can be plugged and unplugged into a variety of plugs.

Anyways, regardless of code, it is just common sense that any electrical plug should be wired in a standard way. Otherwise the next house owner will come along and plug something else into the plug and have potentially disastrous consequences is it isn't wired correctly.

Btw, Travis, when you say you have a 60 amp breaker, do you mean a spare breaker not connected to anything else?

SCOOBY | August 20, 2013

@shop. Actually, you are wrong. A NEMA 14-50 outlet installed to charge an EV is an Electric Vehicle power outlet: "Electric vehicle power outlet or EV power outlet — These are essentially the same as EV charging stations except that they terminate in a normal NEMA- type receptacle and are intended to be used with an EV power cord set that is then plugged into an EV receptacle inlet." They have to follow article 625 which, amongst other things, does not permit them to be used for other purposes.

And I don't agree with "regardless of code, it is just common sense...". I believe in following code.

travis2013 | August 20, 2013

Look guys, I'm not trying to take any short cuts. As I stated before, I already ran all 4 wires 15' from the NEMA 14-50 and the "white or normal" wire is rolled up and not connected in the inside of the box. Please don't tell me to connect it just because there is a connection for it. I've already said I read on the Tesla site not to connect it! I will scour the site till I find it again. Thanks all for your advise and if anyone POSITIVELY knows whether or not to use it please chime in.

travis2013 | August 20, 2013
travis2013 | August 20, 2013

above photo did not work, check out page 4 of this link. It CLEARLY says DO NOT CONNECT THE COMMON WIRE!

SCOOBY | August 20, 2013

The official Tesla guidelines are at:

I'm afraid they do not provide any clarification.

SCOOBY | August 20, 2013

@travis2013 I'm not sure what that document is that you posted a link to. Roadster maybe? Anyway, the correct Tesla document for Model S together with a NEMA 14-50 is the one I linked to above.

JohnHarte | August 20, 2013

@travis2013 I found these statements on page 4 of the document you referenced

"Do not connect all 3 phases of a 3-phase feed."

"Caution: The unused leg (L3 in the illustration) must remain open. Do not connect to a Neutral bar, or to Ground."

Both statements refer to 3 phase power.

travis2013 | August 20, 2013

Trying to post a picture:

travis2013 | August 20, 2013

Yeah!!! Can you explain this?

notice | August 20, 2013

I had my electrician install a NEMA 14-50 next to a HPWC on the same circuit - partly so that if something goes wrong with the HPWC, I have a back-up, and partly to support the possibility of a second electric car in the garage someday. The NEMA 14-50 was wired with a neutral for code - I believe the Tesla adapter simply doesn't make use of it. The HPWC doesn't use the neutral either. (Now I just need the S! 2 weeks and a bit to go...) But the HPWC tests out and glows green ready and waiting for something to plug in to... | August 20, 2013

So those instructions are for 3-phase power which is not what I thought you were talking about. Anyway, I would think the wise approach is to take the fail safe approach. Is Tesla does not need/use the neutral then no harm done, but if NEC requires it to be connected and its not, then it could mean problems down the road for you. Most homeowners policies I have seen usually have some kind of statement that says any work done to the house is in compliance with local building codes.


appljd | August 20, 2013

@schueppert : I think you are correct. Those where instructions for the Tesla Roadster. Never heard of a "Home Connector" for Model S.

notice | August 20, 2013

Some more info:

And yes, comments above assuming 2-phase 240V not 3-phase 208V (most homes are 2-phase and many industrial buildings are 3-phase)

ModelNick | August 20, 2013

I'm installing my own NEMA 14-50 outlet. Luckily, my electrical panel is exactly where I need it to be, so I only have to run it about a foot away.

All white wires and ground wires are connected to the neutral bar.

Is it ok to connect the white and ground wires from the outlet to the neutral bar? See photos below (hopefully they work) :)

unclegeek | August 20, 2013

Is it to code to run NM-B into a knockout on the side of the panel without conduit as shown? I'm planning to do something similar but my 14-50 will be accessible from the other side of the wall instead of same side as shown. I thought I had to use a conduit even if it's inside the wall and not accessible.. wrong?
If this is kosher then I will just go this route.

SCOOBY | August 20, 2013

Yes, because it's a main panel. No if it were a sub panel.

Bob W | August 20, 2013

@travis2013 wrote: "Can you explain this?"

First, there is absolutely no reason whatsoever to leave the white wire unconnected from a 14-50 outlet.

The document refers to a Clipper Creek charging station, a box on the wall used with the Roadster. You asked about a 14-50 outlet. They are totally different things.

The document refers to 2-phase and 3-phase power connections. Very few homes have 3-phase power. Commercial buildings have three phase power (often provide 208 VAC instead of 240 VAC).

The 14-50 is always a 2-phase power connection. The Model S UMC can't accept three phase AC power.

The Clipper Creek Charging Station (which usually has a J1772 ouput), can accept three phase power input. There's a circuit inside the box that takes care of making the necessary conversion to provide 208V output.

Back to the 14-50, the white and green wires are redundant for a reason. The green wire is connected to the metal conduit and the plug. The white wire must NOT be connected to the conduit, only the plug.

The white wire allows a 240V outlet to supply both 120V and 240V at the same time, to any device that needs it. The electrical code allows the white wire to carry current (which it will if you are using a device that has both 120V and 240V components, such as a 240V clothes dryer with a 120V light bulb inside, or an RV with 120V sockets inside). The green wire is not supposed to carry current. It is there for safety, so that if the insulation wears off the hot wires and touches the equipment case or the metal conduit, you will not be electrocuted (and the circuit breaker will see a short and open).

In sum, connect all four wires to your 14-50 outlet, otherwise your installation will almost certainly not pass code inspection (you did get a permit, right?) If your house ever has a fire, for any reason, your insurance company could refuse to pay your claim, based solely on the discovery of "wiring not to code," anywhere in the building. At best you would have major legal hassle. It's just not worth it. Connect the white wire like everyone else does and be done with it.

unclegeek | August 20, 2013

@schueppert Yes I CAN run NM-B like illustrated above? (just want to make sure I got that right)

SCOOBY | August 20, 2013

@unclegeek Generally yes, but check local rules.

PatT | August 20, 2013


Your diagram is definitely relevant. The 208 three phase diagram is not related to the power that most home owners have access to. It is used by factories and hotels that need three phase power to operate three phase motors. If you have this power available, you will also have three transformers feeding your panel.

Your other diagram shows how to hook up single phase 220/240. This is the form of power that is provided to most single family residential customers. If you have this form of power you only have a single transformer and you will get 220/240 between the two hot wires but only 110/120 between either hot and the neutral. The chargers in the car normally only use 220/240 so the neutral is not needed by the car or by the HPWC. The ground is needed for safety.

I have a half dozen NEMA 14-50's around my place. Most of them have the neutral connected because I also allow friends to hook up their RV's and most RV's don't use 220/240 but use both hot legs and the neutral to get 110/120. I also had a long run that I did not run the neutral because of the extra expense. Technically I should have used a MEMA 6-50 (three prong) receptacle but I didn't because I know that the EV chargers that plug into probably use 14-50 (four prong) plugs and may not have the adapter.

Regarding NEMA 14-50 being only used for EV charging -- that is a strange idea. I have charged from several RV receptacles in RV parks. All of them were intended for RV's when they were installed and they charge my Model S and my Roadster just fine.

tes-s | August 20, 2013

My understanding is with a 14-50 outlet, only three wires are connected - two hots and a common - in addition to a proper ground. Just like 14-2 wire is two wires - plus a ground.

I also think a 14-50 outlet is a 14-50 outlet, not a L2 charger. Would you call a 120v outlet in a garage a L1 charger?

SCOOBY | August 20, 2013

Obviously charging at an RV park NEMA 14-50 works. Is it to code? Maybe, maybe not. NEC article 625 applies to any electrical equipment used for EV charging and it does indeed prohibit dual use installations above 200V.

SCOOBY | August 20, 2013

@tes-s. Did you read the code before forming your opinion? NEC article 625 permits Level 1 charging from standard outlets, There is no comparable provision for Level 2 charging. So yes, any NEMA 14-50 outlet used to charge an EV is a part of a Level 2 charging installation.

tes-s | August 20, 2013

@ModelNick: how did you get that wire through a punchout in your panel when it is right next to a stud?

tes-s | August 20, 2013

Fair enough. While a 14-50 is being used to charge an EV, it is part of a L2 charging installation. When it is not being used to charge an EV, is goes back to being a plain old 14-50.

ModelNick | August 20, 2013

@tes-s: I drilled a hole in the stud to run the wire through, then used a bushing to secure the wire in the panel. There is actually a small space between the electrical panel and the stud - enough for me to screw in the bushing.

PatT | August 20, 2013

@ModelNick you might want to see if you can push that big aluminum ground wire as far to the right as you can get it. It looks to be right on top of the hot wires coming from the breakers.

@schueppert I just re-read art 625. I believe that the confusion arises from whether a NEMA 14-50 is being installed as a supply for an EV or does it have another use. If you install it as a RV plug (or if you use only three wires 6-50) as a welder supply receptacle; you do not have to be concerned with article 625. If your local code says you need a permit that is what you get the permit for. Later, when you connect your mobile connector to that supply (or in the RV park) you still don't need to worry about article 625 because the mobile connector has all of those requirements built into it.

travis2013 | August 20, 2013

Maybe You should have started your own thread because I still haven't decided whether to use the neutral connection or not. But anyway are you using 4- 6 gauge wires in that cable of yours? I would at least run some flex and connectors in your installation.

PatT | August 20, 2013

He doesn't need flex as he is using NMSC. He does need a cable staple near the blue box.

If you use single wires you would need flex conduit. But you don't need 4-#6. The ground can be smaller and if you use NEMA 6-50 you don't need the neutral.

AlMc | August 20, 2013

Pat T: Agree that the large aluminum ground is too close to hot leads. If you have enough room you may wish to push it over to the right wall and bring into the right side of the ground bar.

I am not as knowledgeable as some in this debate...but is there any reason you can not or should not connect all four wires?

This is the install I did at home and work and I did ground one at the outlet box (green wire) and one to the receptacle ground.

travis2013 | August 20, 2013

I didn't think that outer shell of his cable was code without flex.

Anyway, I have decided to go ahead and connect the 4th "white/common" wire, glad I already ran it! Thanks everyone for your advice. However, I still an confused about this:

skymaster | August 20, 2013

I have no idea why anyone would install a 14-50 at home to charge their Model S.

After reading up on my options before purchase, I ordered a 6-50 adapter from Tesla.

I installed a 6-50R and will remove it when I sell the house and move.

shop | August 20, 2013

@travis2013 - that diagram you are confused about comes from a Tesla Roadster charger manual. It has absolutely nothing to do with a NEMA 14-50 receptacle. If you do a search in that manual, you don't even find the words NEMA 14-50 anywhere in it.

shop | August 20, 2013

@skymaster - why remove the 6-50 plug?

And yes I agree, I'm not sure why Tesla is still recommending a NEMA 14-50 plug, as a 6-50 requires one less wire (and thus slightly cheaper) and is just as good. Perhaps because the 14-50 can be used for other things like an RV hookup.

unclegeek | August 20, 2013

@skymaster how about the fact you get a 14-50 free with the car and for the price of the 6-50 adapter you can run that extra conductor and have enough money left over for dinner out?

create | August 20, 2013

@skymaster I'm with shop. 14-50 are more abundant in the wild than 6-50.