Let me preface this by saying i did my research, i got an electric car and the charger is limited to 12A draw internally, but it is designed to handle both nema 6-15 and nema 5-15 specs. If you run it at 110 12A it will charge in 9 hours, if you run it at 220 12a it will charge in 4.5.

The adapter already came with a nema 5-15 which i cannot change as it has a temperature sensor in it which i would like to keep, but if i send hot hot neutral through its nema 5-15 connector it would treat it as 6-15 and operate correctly.

I already have a 2phase panel outdoor for my hot tub rated for 50A where the hot tub has a 30A breaker. I will be adding a 2nd 20 amp breaker for this.

The question is as follows, should i run it into a nema 6-15 plug, then build a converter from 6-15 to 5-15, or simply use a 5-15 and wire it hot hot ground. I would be violating code, but adding in an adapter is pointless, the wiring is meant to handle 12 amps regardless of voltage, so i assume a 5-15 should handle 220v 12a without issues.

What are your thoughts?

  • Can you not get a replacement cord from the manufacturer that has the correct plug on it? – ThreePhaseEel Mar 16 '17 at 3:13
  • What make and model is this car charger anyway? – ThreePhaseEel Mar 16 '17 at 3:13
  • It's a Chevy Volt, i asked the manufacturer and they said the 220v charger is aftermarket and costs 1600$, quite a few owners made this modification using a converter, the internals have been dissected and i opened it up myself to double check. Someone is already making a converter cable for it, but i dont see the point of spending 100$ on it when i can simply do it myself. – Costin Mar 16 '17 at 3:14
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    FWIW, a Level 2 EVSE shouldn't cost $1600. You can buy non-portable (home charging station) units for under $800 that let you charge with 32A @ 240V (7680W) and portable units that plug in with a variety of NEMA plugs for under $500. As someone who faced a similar issue (posted to EE SE instead of DIY SE), I'd recommend a bit more research or, as @Harper said, make a cheater cord. – Hari Ganti Mar 16 '17 at 6:14
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    What happens when someone else who isn't aware or forgot that this particular outlet is wired for 200V plugs a 'normal' appliance into it? What will your insurance company say if/when something goes wrong? – brhans Mar 16 '17 at 14:42

Installed fixtures must be correct

Any receptacle which is installed as part of the building must be exactly what it says on the tin. If you are provisioning 240V hot hot ground to the receptacle, and breakering it for 15A, it must be a NEMA 6-15. Period.

The simple fact is, if you provision 240V to a NEMA 5, it will be a matter of time before someone plugs a 120V appliance into it. You know the feeling, you're trying to get something done, you have a 5-15 plug in your hands and you search for the nearest receptacle your cord will reach. Everyone else does the same thing. And that's the problem. Your rush to an immediate goal is no excuse. A reasonable person will foresee that a miswired NEMA 5 will find a victim, just a matter of time. An exacerbating factor is that you're intentionally refusing to pull a permit and get inspected because you know you'll flunk.

Just don't do it. Seriously. Not meaning to be a nag here, just there's a better way to do that thing.

The cheater is the way to go

None of this is legal. But since it's not part of the building, the AHJ (building inspector) doesn't have nearly as much to say about it.

A 6" long homemade extension cord will send signals that makes it far less likely for an innocent person to have an accident. First, there's no logical reason for a 6" extension cord to exist. Second, it's obvious that the plug is weird, *presuming that you use a NEMA L6-15 locking type. Also, label it clearly, and attach it securely to the charger with a cord coupler.

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  • You and a few other people said the same thing, and for peace of mind i agree. Even if it's in an unreachable place, and its a <1% chance of someone plugging in a 110 into it, not a chance worth taking. I used a nema 6-15 with a converter, the converter with 5-15 and the charger that plugs into it are in a locked box and i added zip ties to the connection. Thank you for the advice! For anyone reading this later and wondering. Yes, this works perfectly on 2016/2017 Volts with the charger i linked in the OP, no heat and no issues! – Costin Mar 21 '17 at 0:54

No matter what you do with what ever hacked adapter cables you try to kludge up DO NOT WIRE UP AN OUTLET INCORRECTLY. If you wired an outlet that is normally a service connection for 110-120VAC and made it source 220-240VAC you are just asking for long range trouble and risk.

Best case would be you would be the only one to use it and hopefully not forget and plug in something that blows up in your face making it so you could never drive said electrical vehicle again. Just think of the liability you would have on your shoulders if someone else came along and used this kludged outlet and was killed or maimed. It could be one of your kids for all you know.

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The charger may need to be modified internally to adjust to the higher input voltage. It's not uncommon to use a voltage doubler circuit followed by a switch-mode power supply in a 120 V appliance that needs high current DC like a battery charger.

This internal wiring looks almost the same in 240V input mode and 120V input mode

The voltage double circuit is a bridge rectifier followed by 2 capacitors in series across the DC output. In the doubler configuration the center tap of the capacitors is bridged to the neutral of the 120V AC input. This then provides 360V DC to the switch-mode power supply. To change this over to 240V input you need to cut the link between the neutral an the center tap of the capacitors.

If you don't then you will be feeding 700V DC to components that are only rated to 400V.

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