Clarify Ontario Electrical Requirements for UMC / HPWC

hingisfan · Jan 19, 2015

Hi guys,
I was just getting a quote done for my future outdoor nema 14-50, which will be enclosed outside my garage (see below).
The electrician that is giving me the quote seemed to think that 8 gauge wire was fine (I was thinking 6), and that a shutoff with arms reach of the recepticle was required. (I was hoping to not have to do this)
Is the electrician correct?
My panel is about 100 feet away and inside the house.

andyro · Jan 19, 2015

Electrician here (QC) put the 14-50 outlet inside a nice RV enclosure - hangs nicely (no cord kink). Made by company called Midwest Electric Products, Inc. (Rainproof box, lockable). 8 wire OK for stoves but I used 6 for both outlets. You might need better than 6 for 100' though, that's far - what does a chart say?

hingisfan · Jan 19, 2015

andyro said:
Electrician here (QC) put the 14-50 outlet inside a nice RV enclosure - hangs nicely (no cord kink). Made by company called Midwest Electric Products, Inc. (Rainproof box, lockable). 8 wire OK for stoves but I used 6 for both outlets. You might need better than 6 for 100' though, that's far - what does a chart say?

Link for that enclosure you used?
I like the style in the picture above as I can leave the umc locked in the box and then just grab the wand to use. Works just like a dedicated EVSE and then I can disconnect and take on a trip if I need to.

Doug_G · Jan 19, 2015

The cutoff switch thing is due to a misinterpretation of the electrical code, IMHO, but if the inspectors says you gotta have it, then you gotta have it.

Here's a picture of my ridiculous installation. A switch in series with a plug. Makes no sense whatsoever. But I did find it came in handy as a cord holder.

miimura · Jan 19, 2015

Many inspectors in USA initially misinterpreted the NEC to require disconnect for hard wired EVSE installations. The actual requirement in the NEC is to require disconnect if over 150 Volts above ground or over 60 Amps. A NEMA 14-50 on North American 240V split phase is only 120V above ground and only up to 50A, so it is not required in the States. In addition, any plug-in appliance (EVSE) that has an accessible plug should not need a disconnect since the plug IS the disconnect? A HPWC on a circuit greater than 60 Amps does need a disconnect though.

Cosmacelf · Jan 19, 2015

8 gauge wire for 50 amps can be fine if it has a high enough temperature rating. Don't quote me, but I seem to remember that 8 gauge THHN in conduit works, but typical 8 gauge romex does not.

You shouldn't need a cutoff switch for a NEMA 14-50 outlet.

wayner · Jan 20, 2015

Cosmacelf said:
You shouldn't need a cutoff switch for a NEMA 14-50 outlet.

But do you need one for an HPWC? I had mine installed a month ago but my inspector is coming tomorrow and I hope I don't get dinged by this.

kizagjo · Jan 20, 2015

Mine looks like this:

I'm in Markham. Installed ~March 2014, and got my rebate.

Doug_G · Jan 20, 2015

miimura said:
Many inspectors in USA initially misinterpreted the NEC to require disconnect for hard wired EVSE installations. The actual requirement in the NEC is to require disconnect if over 150 Volts above ground or over 60 Amps. A NEMA 14-50 on North American 240V split phase is only 120V above ground and only up to 50A, so it is not required in the States. In addition, any plug-in appliance (EVSE) that has an accessible plug should not need a disconnect since the plug IS the disconnect? A HPWC on a circuit greater than 60 Amps does need a disconnect though.

I've had that argument with the inspector. Their line is, "no that's obviously an error in the way they wrote it, everything in the standard is phase to phase, not phase to ground."

- - - Updated - - -

LOL that's bad. I didn't show you my Roadster HPC installation. Considering that the Roadster HPC is about 5X larger than the Model S HPWC... the switch box is even bigger:

Cosmacelf · Jan 20, 2015

wayner said:
But do you need one for an HPWC? I had mine installed a month ago but my inspector is coming tomorrow and I hope I don't get dinged by this.

Well, first it all depends where in the world you are. But my understanding of the US NEC is that a dedicated hardwired HPWC does need a cutoff switch (similar to what an outside AC condenser needs). That's assuming the HPWC is hardwired (not via a plug). Also, some inspectors will allow the cutoff switch to be the breaker panel breaker if the panel is within visual distance of the HPWC. Good luck!

wayner · Jan 20, 2015

Cosmacelf said:
Well, first it all depends where in the world you are.

Um, I am in Ontario of course!

Isn't this thread entitled "Clarify Ontario Electrical Requirements for UMC / HPWC". I am pretty sure that Ontario is referring to Canada's most populous province rather than the city in SoCal, especially since this is in the Canadian sub-forum and the OP live in Kingston, Ontario.

RAM_Eh · Jan 20, 2015

For the HPWC you need a disconnecting means.

For a 14-50 outlet you do not, but if the inspector says you do he rules. A lot of the inspectors will play it safe.

wayner · Jan 20, 2015

I guess I need my electrician to come back - the inspector is coming tomorrow. Is a circuit breaker box sufficient? I could use one in my garage anyhow so this could kill two birds with one stone.

Doug_G · Jan 20, 2015

RAM_Eh said:
For the HPWC you need a disconnecting means.

For a 14-50 outlet you do not, but if the inspector says you do he rules. A lot of the inspectors will play it safe.

At 40A the code is pretty clear - you don't need the disconnecting means. The PLUG is the disconnecting means.

Plugs aren't allowed above 40A, due to the risk of arc flash if you pull the plug at full power. So the disconnecting means within sight of the load is a good idea - and required in most jurisdictions.

And yes, if the inspector says you need it, then you need it. The reason my inspector gave is hilarious. He said that if they forget to unplug the car before pulling the plug out of the wall, then they could get a big arc. I pointed out that if they weren't smart enough to unplug the car first, they weren't going to pull that switch either. Didn't convince him of course, but it is complete idiocy.

The "Electric Vehicle Only" sign on my outlet - also required - makes no sense whatsoever. So I can't plug a welder into the outlet? Adding a safety switch makes that illegal? Don't get it.

hingisfan · Jan 20, 2015

For guys that are doing an outdoor Nema 14-50, are they putting in a GFI breaker? or just normal? Does GFI cause issues with the UMC?

Cosmacelf · Jan 20, 2015

I don't think anyone makes a 50A GFCI breaker. As it happens, the Tesla UMC has a built in GFCI anyways.

Doug_G · Jan 20, 2015

Personally I'd install the HPWC outdoors, and dial it back to 40A if that's what your circuit can hack.

hingisfan · Jan 20, 2015

Cosmacelf said:
I don't think anyone makes a 50A GFCI breaker. As it happens, the Tesla UMC has a built in GFCI anyways.

I have one right now on my hot tub circuit!

- - - Updated - - -

Doug_G said:
Personally I'd install the HPWC outdoors, and dial it back to 40A if that's what your circuit can hack.

If you didn't buy new though you could save $800+tax by using the UMC though. (no Ontario EVSE rebate on used)

Doug_G · Jan 20, 2015

hingisfan said:
If you didn't buy new though you could save $800+tax by using the UMC though. (no Ontario EVSE rebate on used)

Well sure, you can save some money by using what comes with the car. But it's nice to have the UMC in the car with you all the time, in case you ever need it. These days buying a second UMC is only slightly less than buying an HPWC.

hingisfan · Jan 21, 2015

Is anyone running the UMC with a 50 amp GCFI breaker? I saw some posts from way back saying that there could be issues in doing this, but nothing lately about it.
Thanks

Clarify Ontario Electrical Requirements for UMC / HPWC

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