220V charging (technical) question

[jordanthompson]

Hi there!
I am having issues with my 220V charger (the 50A wired one, not the 70A wall-mounted one). When I connect it up (wall, then car - not that it matters, I get the same problem either way) the car goes from white, to blue, to red. The light on the charging cable goes from solid green to 3 flashes of green, then one red (continuously). I contacted Tesla yesterday and they downloaded my logs and are reviewing them.

We have two-phase power coming into our house panel (2 x 110V and a neutral - no separate ground.) There are four wires going to the NEMA 14-50 (2 hots, ground, and a neutral.) I traced them back to the panel and both the ground and the neutral go to the ground bar (like all of the other wires coming in.) I checked the voltage at the receptical, and there is 120V to ground, 120V to neutral and 240V between the hots (exactly what I expected.)

When I called Tesla, they told me the charger is very sensitive to voltage differences and fluctuations. I am wondering if the charger needs the ground and neutral to be completely separate? If so, I am screwed because there is no way I am running a separate ground to the panel and separating all of my neutral and ground wires.

Does anyone else have a similar wiring setup (ground and neutral are shared?) I am told this is common in Florida (at least it was in 1985!)

thanks,
Jordan

[dsm363]

I had issues with one of my UMCs with a similar problem (UMC would flash red light). I ended up having to get a new UMC. Does the car charge on a 110V outlet without any trouble?

[doug]

Are you using an old MC240?

I'm pretty sure the neutral blade on the NEMA 14-50 plug isn't connected to anything.

[NigelM]

You can find an install sheet here that advises "installing a NEMA 14-50R receptacle connected to a non GFCI 50A breaker." Do you have a UMC users manual? In there it has a small troubleshooting section.

[pgwoosley]

I had a similar problem which the electrician solved by connecting a short piece of wire between the neutral and ground pins of the 14-50. wall plug.

[jordanthompson]

It seems to charge fine with 12oV (thank goodness!)

I believe I have the new UMC (it looks like the one advertised currently at teslamotors.com).

I'll try the short wire trick now!!

I don't have a UMC manual in my bag of tricks - can you point me to one online?

thanks very much to everyone for your help!

Jordan

[jordanthompson]

OK - that was a bust... For grins, I checked the resistance between ground and neutral at the receptical and it was zero. I tried the jumper wire just to be sure and it still didn't work

[kevincwelch]

I am watching this thread with great interest.

I am having my garage rewired to accommodate the necessary juice to charge the Model S on a daily basis.

Hopefully this issue gets resolved and you can post your solution.

[dhrivnak]

I installed the Nema 14-50 and by code you should have a separate neutral and ground and they should terminate on the ground bar inside the breaker box. I cannot inderstand why that is the code as a jumper wire should do the same thing. And make sure you have a non GFI 50 amp breaker. If you are still having a problem i would check with a friend/neighbor or go to a nearby trailer park and test out the cord. If you have the same problem then it is likely the cord.

Also be sure the 240 is measured from the left to right blades and you get 120 from the blade to neutral and to ground.

[cinergi]

I'd try plugging into someone else's 14-50 to validate whether your UMC is good.