EVSE wiring - 30a vs 40a

[wantonsoup]

I've got the Schneider EV2430WS 30-amp EVSE ready to be installed. I'm confused about the wiring instructions and I'm hoping someone here is enough of an expert to guide me. 30 amps use 10 gauge wiring, but the installation manual for this EVSE says this:

8 gauge / 40 amp setup. I'm confused. I mean the instructions are straightforward obviously, but why is this a 30-amp EVSE if it's connected with 40-amp wiring and breaker? Can/should I use 30 amp / 10 g? 8 g wire is more expensive which is like another $50-100 for this run.

Second question!
I'm also thinking I should have the electrician install a NEMA outlet and wire a plug to the charger, in case I want/need to move it in the garage down the road. What plug is recommended? All I see are 30 and 50 amp ones.

 

[davewill]

An EVSE is considered an "continuous" load. A continuous load is only allowed to use 80% of the circuit's capacity. Doing the math, 30a/80% = 37.5a, which gets rounded up to the next highest breaker available, 40a. Since the circuit is 40a, you'll have to pick a 50a receptacle (there are no 40a receptacles).

 

[wantonsoup]

Okay, mystery solved there. Which NEMA 50amp plug/outlet would you recommend I pick up? I'm having a licensed electrician do the work but I'm buying the parts to save on time and money.

 

[leafedbehind]

Okay, mystery solved there. Which NEMA 50amp plug/outlet would you recommend I pick up? I'm having a licensed electrician do the work but I'm buying the parts to save on time and money.

I have a NEMA 6-50. I think that's the most common plug for 40A EVSE circuits.

 

[davewill]

The Blink that was installed in my garage uses a NEMA 6-50, which works fine. A lot of people like using the 14-50, since it's popular at RV parks and the like, but it requires an extra neutral wire that the EVSE doesn't need and would increase the cost of your install.

The big advantage of a plug in my opinion isn't moving the EVSEs location. After all, if you're going to have to dismount it from the wall and wire a circuit to the new location, disconnecting three wires and capping them off isn't going to be much more bother. The handy thing is being able to power off the EVSE without going and finding the breaker. Just pull the plug. In addition, a lot of localities require a cutoff near the EVSE itself. The plug can be that cutoff, eliminating the necessity of installing a switch.

 

[smkettner]

I used a 14-50 so I can unplug the Schneider and plug in my RV when needed.

You can make a cord with 3 wire #8 cord and connector of choice. The 4 wire 14-50 appliance cords from Home Depot etc. are a bit bulky to to get in a strain relief.

I bought my stuff here:

http://www.stayonline.com

You do not really need to understand the instructions as much as just follow them.

 

[thankyouOB]

seems to me that someone smart enough to buy a LEAF and who has this many questions about basic wiring issues should prolly call an electrician.
$100 for peace of mind, also too, not screwing up your toys and that house you own with the bank.

 

[Nubo]

8 g wire is more expensive which is like another $50-100 for this run.

Well, you'll save a bit, 2 ways. The heavier wire will have less resistance, and dissipate less energy. Also the voltage drop will be slightly less and so the car may charge more quickly, lessening the time the coolant pump has to run, etc...

Very small differences to be sure, but still a consolation

 

[wantonsoup]

seems to me that someone smart enough to buy a LEAF and who has this many questions about basic wiring issues should prolly call an electrician.
$100 for peace of mind, also too, not screwing up your toys and that house you own with the bank.

Umm, I said twice that I'm using an electrician I'm just buying the parts in advance.

Thanks for the help, everyone. I'll pick up some 8/2 NM wire and a 6-50 plug and receptacle.

 

[QueenBee]

The big advantage of a plug in my opinion isn't moving the EVSEs location. After all, if you're going to have to dismount it from the wall and wire a circuit to the new location, disconnecting three wires and capping them off isn't going to be much more bother. The handy thing is being able to power off the EVSE without going and finding the breaker. Just pull the plug. In addition, a lot of localities require a cutoff near the EVSE itself. The plug can be that cutoff, eliminating the necessity of installing a switch.

It's still recommended to turn off the breaker just because the plug is pretty bulky and it'd be easy to get your fingers in there when unplugging it.

wantonsoup, I think your strategy is a good one. Having all the supplies ready for the electrician obviously saves on trips and planning they need to do.

 

[MikeD]

I have noticed that most of the cord-and-plug EVSEs have entirely plastic outside cases, and these plastic (non-conducting) EVSEs (like the Leviton EVB30) say nothing about using a protective cover over the 6-50 receptacle/plug in their installation instructions -- which I take to mean UL considers them safer to use than EVSEs with metal outside cases (like the Leviton models EVB32-8ML and EVB32-5ML whose installation instructions do require a protective cover over its receptacle/plug).

I think the reasoning behind the protective outlet cover requirement is that UL typically requires an outside metal case (that might become electrically energized due to, say, a loose/broken internal wire) to be connected to the "equipment ground" plug connector (so that the breaker will protect a user by tripping if the case does become electrically "hot"). Since a 6-50 plug has relatively long prongs (to provide more surface area for making a good electrical connection, I think), a partially inserted plug allows more possibility for a person (and especially a child) to accidentally touch either of the two "hot" partially exposed plug prongs while simultaneously touching the nearby grounded EVSE case -- a potentially lethal situation.

I rather think that even if you have a plastic cord-and-plug EVSE, it would be a good idea to add a protective cover (even one with a small lock), especially if you have children. Remember wet concrete floors can also provide a path to ground.

An alternative safety measure (Siemens for one recommends it for their (plastic cased) cord-and-plug VersiCharge EVSEs) is using a GFCI circuit breaker, but they are currently relatively expensive (> $100) and last time I checked not available from Lowes or Home Depot. A possible downside is if the breaker causes "nuisance trips" that causes incomplete charging.

Edit Addition: Some cord-and-plug EVSEs (like the Siemens VersiCharge VC30BLKBR and the Leviton Evr-Green 400 EVB40-5PT) are designed to be mounted physically over a flush receptacle, removing the possibility of shock from energized receptacle/plug access (as long as the EVSE remains mounted or the receptacle's power is removed when the EVSE is removed).

 

[wantonsoup]

I rather think that even if you have a plastic cord-and-plug EVSE, it would be a good idea to add a protective cover (even one with a small lock), especially if you have children. Remember wet concrete floors can also provide a path to ground.

Good idea, I'll take a look and see what I can find.

A further safety measure (Siemens for one recommends it for their (plastic cased) plug-and-cord VersiCharge EVSEs) is using a GFCI circuit breaker, but they are currently relatively expensive (> $100) and last time I checked not available from Lowes or Home Depot.

My EVSE specifically says not to use a GFCI as the unit has that functionality built-in.

 

[iluvmacs]

I recently helped a friend install an EVLink in his home, and we were originally going to make it pluggable with a NEMA 14-50 plug & outlet on the wall. However, the electrical inspector rejected this idea, stating that the NEC prohibits you from converting a device that is designed to be hardwired into a pluggable one. So we just kept it hardwired.

I know some people that have done the conversions on their own, and even as an electrical engineer I really don't object to the idea at all, but keep in mind that a code-abiding electrician will probably not do it this way for you. You may have to just have them install a 14-50 outlet connected to a 40A breaker without telling them what it's specifically for, and then put your EVLink on the wall later with a cord attached yourself (and then take responsibility for the "violation" yourself if there are any future issues).

 

[MikeD]

wantonsoup: Looking at document "Electric Vehicle Charging Station EV2430WS–Installation (Rev. 03, 09/2011)" on Schneider's website I see the notation "A ground fault circuit interruptor (GFCI) circuit breaker will override the automatic GFCI reset function built into the charging station.", which is probably what you were referring to.

Reading all of the (English!) instructions I think I was wrong when I referred to EV2430WS as a plastic "plug-and-cord" EVSE before. There is nothing in those instructions that indicates that it is UL listed for "cord-and-plug" connections, and in fact words that seem to prohibit it: "• Follow wiring instructions as marked on the inside of the equipment.", "• Do NOT use or modify this device to be PORTABLE.This device is to be used as permanently mounted equipment only.", and especially "This product must be connected to a grounded, metal, PERMANENT WIRING SYSTEM; or an equipment-grounding conductor must be run with the circuit conductors and connected to the equipment grounding terminal or lead on the product [emphasis mine].". I agree that it still not 100% clear, so you ought to communicate to Schneider directly about whether or not "plug-and-cord" is allowed for this EVSE by its UL listing.

As noted in my previous post there are extra safety problems with an EVSE that has doen't have a completely non-conducting plastic case and is "plug-and-cord", so perhaps this EVSE's case is partially metal.

If in fact it is a "direct wired" EVSE (as I think), then there is no good reason to have a GFCI circuit breaker as I was only suggesting one mainly to protect the user from risk of shock at the the receptacle/plug (the EVSE's internal GFCI cannot protect that, it only protects the J1772 connector and the cable leading to it from the control box).

BTW if an EVSE were "plug-and-cord" connected, and you were using a protective cover, and you were not disconnecting/moving the EVSE occasionally then it is hard to justify the expense of a GFCI circuit breaker, especially if it turned out to be prone to "nuisance trips".

 

[wantonsoup]

Honestly I don't plan on moving the EVSE ever, unless I build a new garage or for some reason need to park the Leaf in a different position in the current garage... and I suppose If need be I could always add the receptacle and plug down the road very easily. Considering this, I'll just have the electrician run the wires to a junction box in the garage, then out to the EVSE. Problem solved. I'd sure regret it if we had to do an insurance claim for whatever and they denied it because of some wiring UL violation.

 

[bryan38401]

the hard wire is a nec code it depends on what year book you are using.the gfi in the scheinder unit will reset itself were as the gfi breaker will not.

 

[MikeD]

bryan38401: You wrote (correctly, I think): "the hard wire is a nec code it depends on what year book you are using.". More specifically I believe it is related to Article 625.13 (Electric Vehicle Supply Equipment) reading in part "Electric vehicle supply equipment rated at 125 volts ... [additional requirements] ... shall be permitted to be cord-and-plug-connected. All other electric vehicle supply equipment shall be permanently connected and fastened in place." (2008 and 2011 versions).

However, a TIA (Tentative Interim Amendment (TIA 11-2) was issued in Oct 2011 that would permit non-portable electric vehicle supply equipment (under certain conditions like no more than 50a) rated up to 250 volts to be cord-and-plug connected. I believe it is this that allows non-direct wired 240v EVSEs (under the required conditions).

"A Tentative Interim Amendment is tentative because it has not been processed through the entire standards-making procedures. It is interim because it is effective only between editions of the standard. A TIA automatically becomes a proposal of the proponent for the next edition of the standard; as such, it then is subject to all of the procedures of the standards-making process."

 

[smkettner]

Did I also see a tentative change to allow about 5' of cord on the plug in?

 

[MikeD]

smkettner: Actually 6', but I haven't seen any cord-and-plug EVSEs with power supply cords more than 1' yet. Here's the link:
http://www.nfpa.org/Assets/files/AboutTheCodes/70/TIA70-11-2.pdf" onclick="window.open(this.href);return false;

 

[smkettner]

Interesting that 120v 15 or 20 amp does not designate a cord length. Does it then remain at 1' max?
Or is it now unrestricted?