Computerizer
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NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 11:12 am

I have the "portable" AV EVSE that plugs into to a NEMA 6-50 outlet, which I installed in my garage. We're thinking about spending some time at my father-in-law's house. He has a NEMA 10-50 outlet in his garage.

I researched the 10-50 and it seems that it's a little strange: two 110V prongs that give you 220V when combined, and a neutral. The 6-50, however, has a hot, neutral, and ground.

What I'm wondering is this: Is it possible to make an adapter from 6-50 to 10-50 so I can use my charger there? There'll be no real ground, so will my EVSE get mad and not actually work?

If it's not possible, we could use 110V charging, BUT his house has no ground. There are a couple outlets that have ground holes in them, but it's not connected to anything. How carefully does the 110V EVSE check the grounding? Will it not function without a true ground? Can I fake it out somehow?

[EDIT: Mine is 6-50, not 5-50]
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smkettner
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 11:19 am

Pretty sure AV has a 6-50 plug

6-50 has 2 hot and ground, 10-50 has 2 hot and neutral. Connect the hots direct and the neutral to ground.

http://www.mynissanleaf.com/viewtopic.php?f=26&t=5504
Last edited by smkettner on Tue Jul 02, 2013 11:24 am, edited 1 time in total.
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Computerizer
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 11:21 am

smkettner wrote:Pretty sure AV has a 6-50 plug

6-50 has 2 hot and ground, 10-50 has 2 hot and neutral. Connect the hots direct and the neutral to ground.
Yeah, I got the numbers mixed up in my head. I edited my original post.

Now that I look at pictures of 6-50 instead of 5-50, it does look fine. As long as the EVSE is fine with ground being neutral (which it should be -- in my house it's the same thing).
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davewill
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 11:52 am

Computerizer wrote:... Now that I look at pictures of 6-50 instead of 5-50, it does look fine. As long as the EVSE is fine with ground being neutral (which it should be -- in my house it's the same thing).
You'll be essentially repurposing the neutral as a ground. Since there's likely only the one receptacle on that circuit, it shouldn't be a problem.
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MikeD
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 12:20 pm

Computerizer: I STRONGLY suggest you have a competent licensed electrician run a new [or OK the old] dedicated circuit for your cord-and-plug EVSE, if you do anything at all.

My (not extensive) understanding is there is a "broken neutral" risk that could occur that could cause anything connected to a neutral to become electrically energized (like metal appliance covers -- including that of an EVSE (although these days most EVSE covers seem to me made of plastic for safety)) -- if the "equipment ground" of such appliances is connected to a neutral instead of a well-grounded ground at the breaker panel. Any electricians out there: please correct me if I'm wrong about this issue.

[Edit Update: I've had more time to think about the above paragraph and could not think of a situation where a "broken neutral" could occur with a 6-50 circuit and create a hazard for the device on that circuit. This may partly explain why 6-50 was chosen (along with lower cost) rather than 14-50 -- which can have a "broken neutral" risk.]

Even if you decide to do nothing with your EVSE after all, IMO having an electrician inspect your father-in-law's house for any serious safety problems that may have arisen since the house was built is worth considering. Going further, it may be a good idea for an electrician to upgrade the panel to the point that at least new safely grounded circuits can be easily added in the future.

arnolddeleon
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 4:45 pm

Ground to neutral in this case is ok because we are assuming there is no current on the neutral conductor because it is not shared w/ anything else (there should only be be one receptacle on the circuit) so there are not120V loads. Older appliances that use 10-30 and 10-50 cords also end up tying their chassis ground to the neutral line.

The EVSE (or the car, I don't remember at the moment) should test for ground so if the neutral/ground wire is broken it will fail that test.

FYI the Neutral and ground buss bars are connected together at the main service panel.

arnold
Last edited by arnolddeleon on Tue Jul 02, 2013 7:40 pm, edited 1 time in total.

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ebill3
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 7:15 pm

I use an adapter with a 10-50 outlet to power the Tesla EVSE that requires two hots and ground. Works just dandy.
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MikeD
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Re: NEMA 10-50 adapter & ground...

Tue Jul 02, 2013 7:43 pm

arnolddeleon: Yes, I agree with you (or what I think you are implying) that an EVSE doesn't cause a special issue (other than possibly service capacity and available breaker slots) for (not too!) older houses built before an additional ground wire was required in its wiring.

A larger question going beyond EVSE installation for such older houses is (and probably one I shouldn't add to this thread): If you are an electrician (or others out there), are there intermediate recommendations on upgrading only part of such a house's wiring short of replacing all wiring w/o an "equipment ground" wire? Something along the lines of replacing 10-30 receptacle/plugs with 14-30s and 10/3 cable and 10-50 receptacle/plugs with 14-50s and 6/3 cable?

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