NEC and EVSE technical question

[sub3marathonman]

I am needing a bit of help figuring out what to do. I had everything set up, with a 50 amp outlet on the back wall of the garage, years ago planning for an electric vehicle (I had an S10-EV but that's another story). I never expected that the vehicle would have to sit outside overnight because it couldn't withstand a bit of heat. SO ...

I have another 240v receptacle in the perfect location. The one problem is it is a 20 amp circuit / receptacle. IF I am reading the NEC correctly, I could put the necessary NEMA 6-50 receptacle in place and be code compliant. However, if whatever is plugged in to the receptacle would draw more than 20 amps, that would be a code violation. The EVSE calls for a 40 amp breaker, but that is for the full 30 amp continuous power it can deliver. For the LEAF, I don't even need a 20 amp breaker. So, plugging in only to the LEAF, everything is fine. But, the EVSE could just as easily plug in to an EV pulling the full 30 amps at some point.

So, would it be NEC compliant with a warning sign by the EVSE notifying the maximum amperage that could be used? Is it possible to "step down" a GE Wattstation to limit it to 15 amps? Is it possible to just replace the short run of wire with heavier wire that can carry the full amperage, and replace the 20 amp breaker with a 40 amp breaker without doing another load calculation?

And yes, these choices are not what was planned for initially, but I'm trying to avoid unnecessarily having to call an electrician in. I would even try to do the load calculations, but I've heard that is very complex.

 

[asinclair]

I think you would be best served to have an electrician look at your electrical service. If the wiring from your panel to the 240 outlet is the right size, and your electrical service could handle the load (again, have an electrician evaluate, in my humble opinion), you could change the breaker to a 40-amp and solve your issue. Just my opinion...

 

[TonyWilliams]

For the LEAF, I don't even need a 20 amp breaker. So, plugging in only to the LEAF, everything is fine. But, the EVSE could just as easily plug in to an EV pulling the full 30 amps at some point.

Yes, the LEAF does in fact need a 20 amp breaker (0.80 * 20 = 16 amps). The LEAF can pull up to about 18 amps at 200-208v.

So, would it be NEC compliant with a warning sign by the EVSE notifying the maximum amperage that could be used? Is it possible to "step down" a GE Wattstation to limit it to 15 amps?

I just did this on a Clipper Creek (changed from 30 amps to 40 amps continous), and while it was simple to do on that EVSE, I have no first hand knowledge how easy it would be on a GE WattStation.

Is it possible to just replace the short run of wire with heavier wire that can carry the full amperage, and replace the 20 amp breaker with a 40 amp breaker without doing another load calculation?

That is the simple answer.

but I'm trying to avoid unnecessarily having to call an electrician in. I would even try to do the load calculations, but I've heard that is very complex.

What is complicated? It's relatively simple, and I suspect you're making MORE complexity by try to avoid simple calcs. Just run the correct 8 gauge wire and 40 amp breaker. Problem solved.

 

[sub3marathonman]

What is complicated? It's relatively simple, and I suspect you're making MORE complexity by try to avoid simple calcs. Just run the correct 8 gauge wire and 40 amp breaker. Problem solved.

OK, if you want to do it the EASY way, that's what I'll try. Thanks for all the help.

 

[sub3marathonman]

I have made some progress, but now I've run into another NEC question.

In the garage, to comply with NEC code, does the NEMA 6-50 receptacle for the Wattstation plug require a tamper-proof cover? Has this changed with a newer revision of the NEC?

 

[davewill]

... In the garage, to comply with NEC code, does the NEMA 6-50 receptacle for the Wattstation plug require a tamper-proof cover? Has this changed with a newer revision of the NEC?

Mine doesn't have one.

 

[MikeD]

sub3marathonman: Assuming you are attaching a 30a/32a EVSE to the NEMA 6-50 receptacle, just make sure that the circuit breaker for it is 40a (and that the circuit wire used is 8 AWG or thicker).

 

[Rauv]

I have made some progress, but now I've run into another NEC question.

In the garage, to comply with NEC code, does the NEMA 6-50 receptacle for the Wattstation plug require a tamper-proof cover? Has this changed with a newer revision of the NEC?

No, it does not need to be tamperproof (tamper resistant), nor does it need to be weatherproof or GFI. Use copper wire, whatever you do. Consider using a larger wire size if you have a long distance from panel to receptacle to reduce voltage drop.

 

[smkettner]

ebay the wattstation (or sell it right here) and get a Leviton 160.

Either way I believe you will need to hardwire to be NEC compliant outdoors and the Wattstation is a no go.

 

[sub3marathonman]

Either way I believe you will need to hardwire to be NEC compliant outdoors and the Wattstation is a no go.

I am not 100% sure about outdoors, but a plug for a 240v EVSE is definitely NEC compliant, at least for the current 2008 and 2011 version. See http://www.mynissanleaf.com/viewtopic.php?f=9&t=792" onclick="window.open(this.href);return false;

What I'm wondering is about a tamper-resistant receptacle cover requirement.

And also, thanks to everyone who replied to my question here.

 

[Rauv]

I have made some progress, but now I've run into another NEC question.

In the garage, to comply with NEC code, does the NEMA 6-50 receptacle for the Wattstation plug require a tamper-proof cover? Has this changed with a newer revision of the NEC?

No, it does not need to be tamperproof (tamper resistant), nor does it need to be weatherproof or GFI. Use copper wire, whatever you do. Consider using a larger wire size if you have a long distance from panel to receptacle to reduce voltage drop.

Oops. I did not read your original post correctly. If your 6-50 receptacle is mounted outside and in a protected area from the elements (i.e damp locations, not wet location as defined in the NEC) then you need a weatherproof enclosure for your receptacle. Article 406.9 of the 2011 NEC reads as follows:

"406.9 Receptacles in Damp or Wet Locations - A receptacle installed outdoors in a location protected from the weather or in other damp locations shall have an enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment plug cap not inserted and receptacle covers closed)."

In my opinion, if you really plan to install youe EVSE outside, I would get the hardwired version of the GE wattstation, or better yet, get Phil's EVSE Upgrade and an extension cord to use an outlet in your garage, not outside.

Lastly, there is no requirement for tamperproof receptacle for inside or outside your garage. Tamperproof receptacles only exist in 15 and 20 amp 120 volt receptacles anyway.

 

[sub3marathonman]

"406.9 Receptacles in Damp or Wet Locations - A receptacle installed outdoors in a location protected from the weather or in other damp locations shall have an enclosure for the receptacle that is weatherproof when the receptacle is covered (attachment plug cap not inserted and receptacle covers closed)."

In my opinion, if you really plan to install youe EVSE outside, I would get the hardwired version of the GE wattstation, or better yet, get Phil's EVSE Upgrade and an extension cord to use an outlet in your garage, not outside.

Lastly, there is no requirement for tamperproof receptacle for inside or outside your garage. Tamperproof receptacles only exist in 15 and 20 amp 120 volt receptacles anyway.

OK, I think now with Rauv's follow-up comment I understand.

On the Wattstation instructions, it showed a receptacle cover, so I thought that meant anywhere it was installed. But with the questions about whether it was going inside the garage or outside, along with the clarification about tamper proof receptacles (which explains why I couldn't find any ), I now see that GE is showing the requirement if it is mounted outdoors, which I hadn't even considered was an option.

So thanks again for the help.

 

[smkettner]

I don't think a 6-50 connector on a 20a circuit will pass code.

 

[MikeD]

smkettner: Rather than leave your last post hanging out there (forever?), here is my $.02 take: On a "common sense" basis of doing what appears less dangerous, your last post suggesting using a 6-50 connector on a 20a circuit is unsafe and probably "code fail" is very reasonable (and apparently like reasoning led sub3marathonman to a much safer alternative).

But a careful reading of the relevant NEC 2011 entries about a "single receptacle on an individual branch circuit" (assuming that accurately describes his short 20a circuit) 210.21(B) (Receptacles) and 210.23 (Permissible Loads) appears to me to support sub3marathonman's understanding that simply adding a 6-50 receptacle to his 20a circuit meets code for as long as he (or anyone else) never attaches an EVSE (or any other "continuous" load) that draws more than 16a (or 20a for "non-continuous" load).

However it is even more important to emphasize that Article 90.1(B) (Adequacy) reads in part "This Code contains provisions that are considered necessary for safety ... but not necessarily ... adequate for ... future expansion of electrical use.".

So it is wise for users to think critically and carefully about future as well as present circuit use -- aka "above code". It seems all the posters of this thread were doing this, btw.

 

[sub3marathonman]

smkettner: Rather than leave your last post hanging out there (forever?), here is my $.02 take: On a "common sense" basis of doing what appears less dangerous, your last post suggesting using a 6-50 connector on a 20a circuit is unsafe and probably "code fail" is very reasonable (and apparently like reasoning led sub3marathonman to a much safer alternative).

But a careful reading of the relevant NEC 2011 entries about a "single receptacle on an individual branch circuit" (assuming that accurately describes his short 20a circuit) 210.21(B) (Receptacles) and 210.23 (Permissible Loads) appears to me to support sub3marathonman's understanding that simply adding a 6-50 receptacle to his 20a circuit meets code for as long as he (or anyone else) never attaches an EVSE (or any other "continuous" load) that draws more than 16a (or 20a for "non-continuous" load).

However it is even more important to emphasize that Article 90.1(B) (Adequacy) reads in part "This Code contains provisions that are considered necessary for safety ... but not necessarily ... adequate for ... future expansion of electrical use.".

So it is wise for users to think critically and carefully about future as well as present circuit use -- aka "above code". It seems all the posters of this thread were doing this, btw.

First, apologies for the delay in responding. Things have been a bit hectic. But thank you to MikeD, and also smkettner and Rauv too. I appreciate everybody's emphasis on safety.

But I Knew It, I just wasn't sure I knew it. I had read before about such a situation where a smaller circuit breaker protected a "larger" receptacle. And yes, under better circumstances, it would be best to avoid such situations.

I did end up converting the existing and properly wired NEMA 14-50 receptacle to the required NEMA 6-50 receptacle. I also was further precluded from using the 20 amp subpanel circuit because of the subpanel setup.