MikeD
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Joined: Thu Jun 24, 2010 6:14 am
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Leaf Number: 592

Re: Best EVSE/charging solution for my situation?

Mon Jan 01, 2018 5:32 pm

wwhitney: Your NEC reference seems to be on point -- PVC 80 is allowed, contrary to what I believed to be the case.

Don't you think, however, that Rigid Metal Conduit protects its contents much better than PVC 80 (i.e. "don't let the perfect be the enemy of the good")?

Also isn't a conducting conduit more likely to cause a (desired!?) breaker trip if a damaged hot wire contacts a metal conduit (because it should be grounded)?

jake14mw
Posts: 171
Joined: Sun Nov 12, 2017 9:53 pm
Delivery Date: 13 Nov 2017
Location: Connecticut, USA

Re: Best EVSE/charging solution for my situation?

Sat Jan 06, 2018 8:52 am

So, I went and purchased the materials yesterday at my local electrical supply house. I decided to only run the 6-3 cable. I ran into one problem. When he laid everything out on the counter, there was a standard metal box for the outlet, and 1 1/4 inch PVC to come down to it. So, I asked the guy, how do I connect the PVC to the metal box? The cutouts were not nearly big enough in the box. He looked at it with a puzzled look. He seemed unsure of how it could be done. So, I just left with what I had, and figured I could ask the question here. Thanks.

wwhitney
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Location: Berkeley, CA

Re: Best EVSE/charging solution for my situation?

Sat Jan 06, 2018 9:13 am

If the PVC is just a chase to protect the cable from damage, and the cable is being pulled through intact with its full sheath, you don't have to attach the PVC to the box. In fact, you'll need to stop it a little short, so that you have room to install a cable clamp to secure the cable to the box. Something like this, whatever size fits your 6/3 NM:

https://www.homedepot.com/p/1-in-Non-Me ... /100113541

You'll need to ream the cut ends of the PVC chase at both openings so that the exposed edges are smooth and won't damage the cable. For a neater look you could install a male adapter at each end and then a plastic bushing on the male threads. And at the box, make sure that there isn't a sharp offset in the distance of the cable from the wall as it goes from the PVC to the cable clamp, if necessary stop the PVC a couple inches further away to avoid this.

And you're going to bond the metal box directly, right?

Cheers, Wayne

jake14mw
Posts: 171
Joined: Sun Nov 12, 2017 9:53 pm
Delivery Date: 13 Nov 2017
Location: Connecticut, USA

Re: Best EVSE/charging solution for my situation?

Sat Jan 06, 2018 1:24 pm

wwhitney wrote:If the PVC is just a chase to protect the cable from damage, and the cable is being pulled through intact with its full sheath, you don't have to attach the PVC to the box. In fact, you'll need to stop it a little short, so that you have room to install a cable clamp to secure the cable to the box. Something like this, whatever size fits your 6/3 NM:

https://www.homedepot.com/p/1-in-Non-Me ... /100113541

You'll need to ream the cut ends of the PVC chase at both openings so that the exposed edges are smooth and won't damage the cable. For a neater look you could install a male adapter at each end and then a plastic bushing on the male threads. And at the box, make sure that there isn't a sharp offset in the distance of the cable from the wall as it goes from the PVC to the cable clamp, if necessary stop the PVC a couple inches further away to avoid this.

And you're going to bond the metal box directly, right?

Cheers, Wayne



Thanks for your help. I understand most of what you said and it makes sense. When you ask if I am going to bond the box directly, I'm sure what you mean. I plan on nailing or screwing the box into a stud on the wall. Is that what you mean?

wwhitney
Posts: 740
Joined: Sat Jul 17, 2010 10:10 am
Delivery Date: 01 Apr 2011
Location: Berkeley, CA

Re: Best EVSE/charging solution for my situation?

Sat Jan 06, 2018 1:47 pm

jake14mw wrote:When you ask if I am going to bond the box directly, I'm sure what you mean.

No offense, but it seems like this project is a stretch for you. Do you have someone local who is more knowledgeable and can look over your work?

To bond in this context means to provide a low impedance connection (good at carrying current) between normally non current carrying metal parts of the electrical system (like the metal box).

Since you are using a metal box, the ground wire in the 6/3 NM needs to bond the box directly before going to the receptacle you'll be installing. [The screws holding the receptacle to the box will bond the two together, but the bonding of the box has to be independent of the device.] I see that 6/3 NM has a #10 ground wire in it. Your metal box probably has a raised area in the box with a tapped #10 hole in it. It may also have a ground screw in the hole; if not, you need to buy one of these or equivalent:

https://www.homedepot.com/p/Ideal-Combo ... /100134430

[I don't remember if it has to be a green screw, I think you probably could use any 10-32 machine screw of appropriate length.] With #12 wire, I would usually just leave the bare ground wire a little long, wrap it in a 270 degree loop around the ground screw, tighten the ground screw, and then land the free end on the device. I think with #10 copper that will still work. Do not he-man the ground screw, it is easy to strip the threads on the screw (but if you do, usually the threads on the steel box are tougher and still OK, so you can just replace the ground screw.)

You could also switch to a non-metallic box and avoid this bonding issue.

Cheers, Wayne

wwhitney
Posts: 740
Joined: Sat Jul 17, 2010 10:10 am
Delivery Date: 01 Apr 2011
Location: Berkeley, CA

Re: Best EVSE/charging solution for my situation?

Sat Jan 06, 2018 1:58 pm

wwhitney wrote:You could also switch to a non-metallic box and avoid this bonding issue.

Simplest way to do it would be to use one of these:

https://www.homedepot.com/p/Leviton-50- ... /202077645

The receptacle and the metallic back plate of the self-contained box are one piece, so you just need to land the ground wire in one place. Plus the box comes with a cable clamp.

Cheers, Wayne

jake14mw
Posts: 171
Joined: Sun Nov 12, 2017 9:53 pm
Delivery Date: 13 Nov 2017
Location: Connecticut, USA

Re: Best EVSE/charging solution for my situation?

Sun Jan 14, 2018 5:00 pm

Well, completed my Level 2 install yesterday. Very happy with it. It really helps make the care more usable. Thanks to everyone for all your help!

GlennD
Forum Supporter
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Re: Best EVSE/charging solution for my situation?

Sun Jan 14, 2018 7:44 pm

Tesla by the number of cars sold sets the standard. For their 40A EVSE they use a 14-50 plug. That means that others consider the same thing. For sure you can get a Clipper Creek unit with that plug. A lot of cheap Chinese units also use that plug. Also 40 or 50A range cables are cheap. On Amazon or eBay either one is less than $20 shipped. For that reason I use range cables on the OpenEVSE units I build. They are a commodity.
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Back to a Cirrus White 2017 B250e

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