Plug-in EVSE - safer to leave it plugged in all the time, or should I unplug/plug every day?

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Kieran973

Well-known member
Joined
Jun 19, 2018
Messages
170
Location
near NY, NY
I'm talking to an electrician about charging options where I live. I'm not sure which type of EVSE I'm going to go with yet (L1 vs. L2, # of amps, etc. - it depends on a lot of factors related to the wiring in my place), but I do know it will be a plug-in EVSE (not a hardwired one). So my question is: what is safer as a regular, year-round practice, leaving the EVSE plugged into the wall permanently, or unplugging it and plugging it back in every day? It seems like if you leave it plugged in permanently, the danger is that it's always drawing at least some amount of electric current. But if you unplug it and plug it back in every day, the danger is that the outlet and the EVSE will wear over time. What do others on this forum do/think? Thanks.
 
Kieran973: You asked about a particular SAFETY issue -- more broadly IMHO the charging circuit should be:
1) dedicated (i,e, only a single outlet) -- don't want another circuit device that might cause overloading
2) outlet receptacle NOT a locking type -- don't want to increase the possibility of ripping the receptacle/cord apart by a large force (think speakers at a drive-in movie if you're old enough)
3) protected by GFCI breaker -- to greatly reduce shock risk while plugging/unplugging
4) appropriately located -- you want to reach the charging port w/o using an extension cord (also want to reduce tripping danger)
5) preferably indoors or, if not, appropriately "weatherproofed" -- water makes for a dangerous ground (why GFCI is so valuable)
6) not within reach of a permanent ground -- if possible you want to avoid the possibility of touching a live prong and a ground at the same time (why GFCI is so valuable)
7) use plugin EVSE providing high temp protection at plug -- to detect loose connection(s) at receptacle (especially important if EVSE unplugged frequently or high current EVSEs). I know Nissan EVSEs since 2013 MY have provided this as they have Leaf Owner's Manual documentation, but I don't know the EVSE model # for them.
10) any other common sense precaution -- !!

Note that most of these concerns are eliminated by choosing to install a direct wired EVSE -- significantly safer and there are more options to choose from with direct wired EVSEs (for example, like "Share2" EVSEs from Clipper Creek that allow two such EVSEs to operate safely when your home's service only has capacity for one EVSE to charge at a time).
 
Kieran973 said:
So my question is: what is safer as a regular, year-round practice, leaving the EVSE plugged into the wall permanently, or unplugging it and plugging it back in every day? It seems like if you leave it plugged in permanently, the danger is that it's always drawing at least some amount of electric current. But if you unplug it and plug it back in every day, the danger is that the outlet and the EVSE will wear over time. What do others on this forum do/think? Thanks.
I have a Level 2 EVSE. It is plugged into a 30A outlet in my garage which is on a dedicated circuit. I have owned it for something over 5 years. I have never unplugged it from the outlet. Other than for an LED indicator light, why do you think the EVSE draws power when not in use?
 
I now charge almost exclusively at an outlet in the parking garage at the mall where I work. But when I was charging at home I left the EVSE plugged-in all the time. As you mentioned, I did that to avoid wear and tear on the outlet. If you do leave it plugged-in all the time, just make sure you have some way of holding it in place, so that the weight of the EVSE is not on the outlet.

If you want to be very green and eliminate all energy usage when you're not using it, just add a wall switch to control the outlet.

Check Amazon, there are several multi-voltage, multi-current EVSEs that will give you lots of flexibility.

Ron
 
Dooglas said:
I have a Level 2 EVSE. It is plugged into a 30A outlet in my garage which is on a dedicated circuit. I have owned it for something over 5 years. I have never unplugged it from the outlet. Other than for an LED indicator light, why do you think the EVSE draws power when not in use?

My EVSE has a WIFI connection, a tiny Linux computer as well as some other electronics. Total draw is about 1 W typical, manual says "Less than 9 Watts".
 
WetEV said:
My EVSE has a WIFI connection, a tiny Linux computer as well as some other electronics. Total draw is about 1 W typical, manual says "Less than 9 Watts".
I see you live near Seattle, so your electrical rate must be something aroung 10 cents per kwh. A constant draw of 1 W would be something less than 8 cents a month or about 90 cents per year. Your call.
 
Thanks, everyone - those comments were helpful. After reading everyone's thoughts and thinking more about it, this is what I'm leaning towards doing:

I rent the 2nd floor apartment in a three floor house. There's a detached garage in the driveway with working 120V outlets but some pretty old and suspect wiring. My original plan was to park in the driveway in front of the garage and just trickle charge on one of these 120V outlets since my work commute is only 11 miles one-way. But the garage seems like too much of a disaster (structurally it's in bad shape too), so I'd like to find a charging solution using the electricity in the main house. I was looking at the electric panel in my apartment, and I noticed that there's a 20 amp circuit breaker labeled "dedicated line" which connects to an unused outlet in a "bedroom" (more of a glorified closet in the New York area) that I also barely use. So I was thinking I could pay an electrician to run more 20 amp wire (encased in metal piping) from that unused outlet, down the outside of the building, and to either an exterior outlet in the driveway, or a hardwired EVSE in the driveway. The driveway is probably 30 feet down from my apartment. I'm actually leaning toward the hardwired option - getting a Clipper Creek LCS-20 installed on the outside of the main building, and having the electrician hardwire it to the 20 amp circuit coming down from my apartment. But if for whatever reason this doesn't work, my next choice would be the LCS-20P (plug-in version) with all the appropriate waterproof covering over the outlet itself. Does this sound like a good idea? I realize there are much faster L2 charging options, but the wiring on the dedicated circuit is only 20 amps and I'd rather not pay for a brand new circuit (especially since I don't own this place), hence the merely 16 amp EVSE. Do other people on MNL charge at 16 amps on a 20 amp circuit? This would be for a 2018 Leaf. I'd probably charge twice a week, between midnight and 8 am, for 6-7 hours at a time. Thanks.
 
If that 20 amp 'dedicated line' is 120 volts instead of 240, then your best option would be to use a portable charging cable that can be set to 16 amps at 120 volts, and just mount it semi-permanently. The charging stations you reference are 240 volts, so what you'd want for an actual charging station is this:

https://store.clippercreek.com/level-1-16-amp-ev-charging-station-acs-120
 
Kieran973: As you may already know from talking with your electrician, if the 20a circuit is in fact only 120v and, say, using NM-B 12/2 cable, it may still be possible to convert to 240v (suitable for a L2 EVSE) using that same wiring if there is room in your breaker box for replacing the 120v breaker with a 240v breaker and there is sufficient capacity in the apartment's service.
 
Kieran973: I just looked at Clipper Creek's info on the LCS-20/LCS-20P that you referred to and noticed that their available plugin versions provide for only the following 4 plugs: NEMA 6-50, 14-50, L6-30, and 14-30

It does not provide a 6-20 version, which I find curious, which I would think is the appropriate plug for you (if you decide plugin). I did see a post from 2016 from someone who installed a NEMA 6-20P on their LCS-20P and stated they had no problem with it. I will try to ask Monday if there is a good reason for no 6-20 option.

BTW note that all lock plugs (like L6-30) are prohibited in the current NEC.
 
Kieran973 said:
...I realize there are much faster L2 charging options, but the wiring on the dedicated circuit is only 20 amps and I'd rather not pay for a brand new circuit (especially since I don't own this place), hence the merely 16 amp EVSE. Do other people on MNL charge at 16 amps on a 20 amp circuit? This would be for a 2018 Leaf. I'd probably charge twice a week, between midnight and 8 am, for 6-7 hours at a time. Thanks.

I've been charging at 240V/16A since 2012. At the time that was the max rate for LEAF. More importantly it was as high as we could go without serious expense. In any case, 16A has been more than adequate. And I think larger pack sizes actually reduce the need for higher at-home charging rates. But of course it depends on your particular situation. For example, someone who drives a lot and has a time-of-use electric plan could use a faster charge rate to place more of their charging in the cheaper TOU window.

As far as unplugging an EVSE, ours has a plug and every few months I will unplug it and plug it back in. The idea being that this helps wipe oxidation off the contacts, while keeping the lifetime plug/unplug cycles low enough that wear is not a concern.
 
Here's one with a 6-20 plug good for 16a. Note these EVSEs are generally 120v/208/240v compatible so it would work on 120v and also 240v if you go that route by simply replacing the plug or making a plug adapter. It says UL "recognized" and has a nice long(23 or 29 1/2' cord).
https://www.amazon.com/OrionMotorTech-Electric-Universal-Plug-EVSE-Recognized/dp/B073F26KZZ/ref=sr_1_17?s=automotive&ie=UTF8&qid=1532207722&sr=1-17&keywords=level+2+ev+charger
 
All great points, everyone. Thanks.

MikeD: why do you think that a NEMA 6-20 outlet is the best one?

I'm still not sure whether to go with hardwired or plug-in. Since it will be an outdoor EVSE, mounted on the exterior wall of the building, a hardwired EVSE seems safer. Clipper Creek recommends hardwired for outdoor EVSEs, but then, confusingly, their plug-in units are rated for outdoor use. Plus, I rent this place and it would be nice to be able to take the EVSE with me when I move, to not just abandon the whole EVSE when my lease is up. Is it really less safe to get a plug-in and just put the outlet inside a waterproof box?

Of course, I'll have to explore whether the 20 amp line is 120V or 240V (as others pointed out), and then see how this affects my options....
 
If it is easier, there's no problem installing a 6-30 receptacle as the only load on a dedicated 20 amp circuit. For a single outlet circuit, the only requirement is that the receptacle rating should not be less than the circuit rating.

Cheers, Wayne
 
Kieran973: The NEC states MINIMUM requirements, many of which are quite complex -- and without explanation (although the NEC Handbook -- and other sources -- attempt with varying success towards its better understanding). And these requirements can change over time, especially in regards to evolving technology like EVSEs.

Although as best as I can tell, wwhitney's single receptacle reading of the current NEC is correct, to me it makes good sense to go BEYOND NEC, especially if I feel assured of better safety through increased simplicity and understanding.

I very much like the concept that if my device's plug fits into a receptacle (especially one that is on a dedicated circuit), then I can feel confident the circuit will have the capacity of safely supplying the required load to that device. So, for example, using a 50a rated receptacle/plug, say NEMA 14-50, for a 20a EVSE on a 20a circuit eliminates that confidence for that receptacle -- and confuses the load requirements of the device as well (although one can argue that it allows the EVSE to also be used at RV camps where 14-50R is commonly available).
 
MikeD said:
I very much like the concept that if my device's plug fits into a receptacle (especially one that is on a dedicated circuit), then I can feel confident the circuit will have the capacity of safely supplying the required load to that device.
Please note that for a typical receptacle circuit, this expectation is not met. It is easy to plug in two 1800W loads on the same 15A or 20A receptacle circuit, and the circuit will not have enough capacity. So whenever plugging in a high power load, it is important to know more about the circuit than just the receptacle configuration.

Cheers, Wayne
 
wwhitney: Aren't we talking about dedicated receptacle circuits? The NEC has different rules for non-dedicated receptacles, where I think you will agree the ratings of the circuit and the receptacles are required to coincide or nearly so, which makes a lot more sense? I basically agreed with you, I don't understand your nit-picking about a simple multi-receptacle overloading issue (not being addressed here) that everyone should already have a clear understanding of?
 
MikeD said:
Kieran973: I just looked at Clipper Creek's info on the LCS-20/LCS-20P that you referred to and noticed that their available plugin versions provide for only the following 4 plugs: NEMA 6-50, 14-50, L6-30, and 14-30

It does not provide a 6-20 version, which I find curious, which I would think is the appropriate plug for you (if you decide plugin). I did see a post from 2016 from someone who installed a NEMA 6-20P on their LCS-20P and stated they had no problem with it. I will try to ask Monday if there is a good reason for no 6-20 option.

BTW note that all lock plugs (like L6-30) are prohibited in the current NEC.

It is the typical Chinese unit lacking GFCI. Using UL recognized components means nothing. The entire unit has to be recognized. As I understand it even making the unit plug in when it was tested for direct wire in means another test..
 
I wonder. LA requires UL approved EVSE's. The Tesla is favored by many Hollywood High Rollers. How do they charge the cars when the supplied EVSE is not UL approved?
 
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