NEMA 6-50 or 14-50

[tangible1]

We have a different opinion of what constitutes an "expensive charging device outdoors" - I'd call a $350 wall connector very inexpensive. If the vehicle is often stored outdoors why would I have a charger indoors, needing a cord to run through a door or window?

$300 is very inexpensive for an installation, normally the GFCI breaker is over $100 alone not to mention the other materials needed. Perhaps your install was much cheaper than the average install is. The MC is worth a couple hundred dollars regardless if you got it free or pay for it. A WC is very similarly priced or $100 more. There is most likely a slightly higher cost to most buyers installing an 14-50 outlet with a MC than a WC, and resulting in an inferior product. Perhaps your case it is cheaper or you are using an old electrical code that doesn't have GFCI protection, in which case your install is also less safe. Of course you and any homeowner is fine to use whatever option you want, but I can think of extremely few cases it makes sense to recommend someone install a MC over a WC.

you can purchase Hubbell 14-50 at an electrical distributor for 45 bucks
as well, the same electrical distributor sells a 60A GFCI breaker for 65.
I'm in SoCAL. My electrician charged 225 for install including wire run, which was less than 8 feet to the panel including panel drop length.
of course, all this was just before the EV subsidies by Edison and the Feds began. Now, electricians know 700 is the subsidy and that's what they charge.

 

[tangible1]

So then the MC is almost never in the vehicle, seems to eliminate the entire point of having one as a backup or emergency charger.

A MC with additional connections at the receptacle and plug will always have more possible points of failure. Perhaps its an insignificant difference to you.

The plug is also a point that kids could think is fun to unplug or play with, etc - So I'd consider it to have safety risk. A half inserted plug could have potential to kill someone especially without GFCI, but even with GFCI across two hot legs.

sure, we can hypothesize anything to rationalize choices

 

[flai54]

Doesn't surprise me at all, actually. In my complex there are a great deal of EV's that don't have a charger in their parking spot. They're most likely getting charging at work or at superchargers. To me this is not at all appealing, but I'm fully aware a ton of people are doing it.

To anyone with some electrical experience, it is truly trivial to cap off some wires and put a plate over a gang box, but I understand some might find it daunting.

I do agree 48A vs 32A is not significant for most. In fact, I try to charge at the lowest speed that I find convenient, which I've determined to be somewhere around 24A.

Overall, however, I weigh reliability and safety heavily and just because mobile connectors are "running in spec" does not mean I want to use them if a better alternative is available. But this is all about priorities and tradeoffs ... as a personal example, I was extremely tempted to install a wall connector at our in-laws, but after some difficulty in iterating with electricians and other family members, opted for a plain old 14-50 outlet with a lockable in-use cover. We are only there about twice a year anyway and will simply bring our mobile charger and charge conservatively ... not worried about it in the least.

But make no mistake ... if it was my house and I was planning to be there for while, the wall connector would be going in. Less points and modes of failure is a fact.

I agree with you in that there is no one size fits all for everyone. For those that require an installation of their EVSE outdoors, 100% that should be the wall connector option regardless for safety reasons since the wires go directly into the enclosure. I know there are ways to try to add a NEMA 14-50 outlet outdoors but adding a waterproof enclosure box around the NEMA 14-50 outlet but I don't think its worth it. Other reasons for opting for a wall connector could be if they plan to have multiple EV cars and want the flexibility to add a secondary wall connector to their 2 car garage to do load sharing off of a 60A circuit. In my situation, I just have a 1 car garage in a condo complex so I don't need to worry about load sharing.

In terms of the NEMA 14-50 outlet installation, definitely agree that there can be more points of failure than a hardwire especially if the electrician does not do a good job of tightening the 6 AWG wire to the contacts of the NEMA 14-50 outlet and more importantly if you are not using a Hubbell 14-50 outlet from the start instead of the cheap kitchen grade Leviton NEMA 14-50 outlet. For me I didn't even want to entertain using any other 14-50 outlet than the Hubbell outlet with full brass connectors so I ensured I bought that Hubbell outlet and watched the electrician grounding/tightening the contacts to the electrical box correctly during installation. Most of the points of failure and dangers of using a NEMA 14-50 EVSE is not the actual EVSE itself but rather then connections inside the electrical outlet box due to poor choice of outlet materials and installation.

 

[Jerryr]

I’m a belt and suspenders kind og guy. I have mobile chargers in the trucks of our 2 teslas. And a Wall connector on a 60 amp circuit in the garage. No plugging and unplugging a mobile connector and I enjoys the 40 amp 11 kw charge capability of 5he Wall Connector..

At our cabin I have a mobile connector only because I already had 2 50 amp RV outlets on the property. I’ve got a mobile connector permanently plugged into one outlet in the shed‘s sub panel. It’s a 60 amp sub panel and I can only comfortably charge at 30 amps due to other stuff the panels supplying. I have considered getting the new universal wall connector and installing it on the outside of the house with a 60 amp setup. I can use the existing 6AWG THWN wiring that supplies the 14-50 and replace the breaker with a 60 amp breaker. If only I could purchase a wall connector at the $350 price it was last year. Oh well, It’s only money.

 

[tangible1]

I guess poster never said it was a professional electrician doing that $300 install, could be self install or illegal unlicensed work. Yes, I can't imagine a licensed electrician doing an install for that price.

licensed pro electrician

 

[tga]

I really like everything with this post except this one sentence. Why would you choose lower amps? It uses more electricity (vehicle sleeps less), would leave the pack at higher SOC longer with scheduled charging (higher degradation), and even at full 48amp is very low charge rate relative to max charging speed (11kw vs 250kw)?

Only reason I would do that is concerns about the amp limit of the house.

There's another reason, but it's less applicable in the days of (relatively) slow L2 charging.

Power losses due to resistive heating increase with the square of current (P=I^2*R). In the "before times" when Roadsters could charge at 70A and dual charger S's could go to 80A, we often dialed down the current to minimize heating (good for long electronics life and power savings). I think the most efficient charging for an S was around 40A, if I recall correctly.

My parents installed an 80A wall connector. I used to charge at 56A (80A/sqrt(2)) at their house to cut heating in half vs 80A. Charging over 40A had the added benefit of testing the second charger (it was only used at >40A).

 

[MacO512]

There's another reason, but it's less applicable in the days of (relatively) slow L2 charging.

Power losses due to resistive heating increase with the square of current (P=I^2*R). In the "before times" when Roadsters could charge at 70A and dual charger S's could go to 80A, we often dialed down the current to minimize heating (good for long electronics life and power savings). I think the most efficient charging for an S was around 40A, if I recall correctly.

My parents installed an 80A wall connector. I used to charge at 56A (80A/sprt(2)) at their house to cut heating in half vs 80A. Charging over 40A had the added benefit of testing the second charger (it was only used at >40A).

Good point.

Yeah I put 6 gauge on my WC and the run is about 7 feet to the main panel on the other side of the garage wall so pretty irrelevant to me. On a long run and if the wiring is close to the breaker limit perhaps this could become a concern. I'd still think the car sleeping would use more power than any additional resistance/heat waste. Although if lower current reduced heat I might be tempted to do that more to reduce long term wear on the wire insulation.

 

[Shelby Griggs]

Just met with my electrician today due to some error codes from wall connector and on car display, reported in detail on another post here today. My WC is about two months old and I wanted to verify issues weren't due to any install error. I watched everything and all checked out. Torque was actually checked with a torque wrench, by the book!

Discussion turned to WC vs MC with a 15-40. They don't recommend a 15-40, even with industrial quality plugs they have seen some failures or near failures after 2-3 years. Overheating and melting/burning issues even with installing commercial outlets and wired by a pro electrician. YMMV, just reporting what I was told.

My install of the WC has about a five foot run of THHN in conduit. I noticed it warms when in use, so took some temps today, about a 20F increase at the breaker, about 15F of the conduit and about 10F of the WC cable to the car after 1-3 hours of charging. So, a continuous 40A definitely creates some heating even with the WC.

 

[3sr+buyer]

In terms of the NEMA 14-50 outlet installation, definitely agree that there can be more points of failure than a hardwire especially if the electrician does not do a good job of tightening the 6 AWG wire to the contacts of the NEMA 14-50 outlet and more importantly if you are not using a Hubbell 14-50 outlet from the start instead of the cheap kitchen grade Leviton NEMA 14-50 outlet.

Note that there are lots of other brands and models of 14-50 outlets, most of which also have full size brass contacts to the plug blades (unlike the Leviton 279-S00 that has half size steel contacts with higher resistance and heat generation).

Main difference with the Hubbell and Bryant 14-50 (but not 6-50) outlets is an improved wire clamping mechanism that is easier to install properly and harder to install poorly than the usual screw-down wire clamping. However, careful installation of screw-down wire clamping avoids problems.

 

[Jerryr]

I still think it matters when it comes to the current owner of the house on whether they are planning to stay in the short term or long term. Having flexibility with a NEMA-14-50 plug if you move out is much easier to unplug your mobile charger than to figure out what you will do with 3 open wires when you disconnect your wall charger when you move. If someone moves in and has their own EVSE, most likely it would not be wired and using a NEMA 14-50 plug.

Installing a Wall connector with 4 wires makes it easy to replace the wall connector with a 14-50R when selling the house, if you want.

If it was installed with 3 wires (no neutral) there are several options.
1- just install an outlet box, cap the wires, install a blank plate and disconnect the wires from the breaker.
2- install an outlet box and a 6-50R

My cabin has an outlet with a blank plate on the screened porch. There is an unused 50 AMP GFCI breaker in the panel that fed a hot tub on the porch at one point.

 

[zroger73]

Some things I'd like to point out (and I apologize if they've already been stated)...

1. There's no reason to pay more for a Hubbell 9450A than a Bryant 9450FR receptacle. They're both made by Hubbell in the same factory and are the same quality.

2. Hubbell and Bryant both sell industrial and residential-grade receptacles. Brand alone isn't sufficient - you have to look at the model number as well!

3. A Wall Connector can have a lower net price than a Mobile Connector. In my case, my electric company offered a $250 rebate for fixed, but not portable EV charging equipment. This made the WC cheaper than the MC. And, there's a 30% tax credit for fixed, but not portable EV charging equipment on top of that.

4. If you can only have charging solution, I recommend a MC since it can be used at home or away.

5. Ideally, I recommend two charging solutions so you have a backup - a WC at home for the fastest charging (just in case you need it) and a MC that you can keep with you or use as a backup in case the WC goes down.