Have Plug-In now... convert to Hardwired?

[dtbaker61]

Hi there,

My home garage currently has a NEMA 6-50 50A socket. Been reading about hardwired is better. I'm wondering for my situation, is it worth converting over or can I safely use the current socket for L2 charging?

as long as your plug-in charger pulls no more than 32-36 amps thru a 50a breaker, and the wiring to the socket is 6-awg with 8awg ground (for a 'short' run <25'), the plug/socket should be fine.

I prefer to leave a socket if wiring is good so that it *could* be used for temporary generator backfeed in case of power outages (after isolating from grid by turning off the MAIN breaker, and disconnecting any Solar interconnection circuit)

Sponsored

 

[dgilles428]

When my 14-50 was originally installed I opted for the 60A breaker and appropriate wire gauge because I knew I'd eventually go hardwired.

I did a 48A Wallbox Plus install myself about a month ago now and it's been great. 11.1kW charging is a world of difference over a routinely overheating Ford Portable (Webasto) EVSE that maxed out at 7kW at the best of times.

I got the Wallbox Plus as an 'open box' item on Amazon for about $100 off retail. Everything was in the box and unopened (hardware packets, etc)...it's just somebody opened the box so I guess they couldn't sell it as 'new'.

I have been using plug-in for 3 years and would never want a hard wired EVSE. When I have friends that stay over and need to charge their Tesla's I unplug my EVSE and fun a 6 ga extension cord to the front of the garage so they can charge in the driveway, even had to do that once myself when a garage door spring broke with my car outside. Of course it also depends on how fast you need to charge, I prefer 6 kw and can always charge completely overnight. Only if for some strange reason you need to charge really fast would a permanently mounted EVSE be needed.

 

[Chuck]

Hi there,

My home garage currently has a NEMA 6-50 50A socket. Been reading about hardwired is better. I'm wondering for my situation, is it worth converting over or can I safely use the current socket for L2 charging?

I've been using a plug in for 3 years without issue.

 

[dbsb3233]

Pretty sure it was 8 AWG copper. But it could have been 6. I don't remember right now.

Edit:...it probably was 8 AWG since they had it on a 60A breaker.

8 would be awfully weak for a 60A. I'd definitely go at least 6, if not 4, for 60A (as your chart recommends). They used 6 for my 50A.

Remember that an EVSE draws max power continuously for up to 12 hours. That's a lot more stress than a dryer or oven or even A/C that's only on for maybe 30 minutes at a time before shutting off and being able to cool down.

 

[Jtbuster]

As have been said in past :


The code is very clear that you cannot install an evse that pulls 48 amps on 6-2. The issue is that that clarity requires looking at several different places in the code book and understanding the difference between maximum over current device and minimum circuit ampacity.





An EVSE is considered a continuous load.



NEC Article 100 defines continuous loads as loads that are expected to run continuously for 3hrs or more .



The minimum circuit ampacity (amount of current wire has to be rated for) is 125 percent of the continuous load, in this case 48*1.25= 60amps



NEC 210.19(A)(1) code reference for that.





Romex cable can only be used at the 60 degree c rating on the NEC ampacity tables.



NEC article 334.80 code reference for that.





Then, we need to look at the NEC ampacity tables. At 60c, #6 (6/2NM cable) is only rated for 55 amps. Commonly, people misapply the round up rule that allows you to round up the over current device (breaker) past the MOCP calculation to the next standard breaker size, which for 55 amps could be 60. However, we are calculating minimum circuit ampacity, not maximum over current protection, so the round up rule does not come to play.



So our options are to use 4/2NM which is rated at 70amps @ 60c (which is impossible to find) or to use #6thhn, which can be rated at 75c as long as the breaker and evse terminals are also rated at 75c (most are) which is rated at 65 amps.



NEC 310.16 reference for that.

 

[Mach-Lee]

I’ll put this here:

EV Breaker Size Reference

 

[Kyle]

Hi there,

My home garage currently has a NEMA 6-50 50A socket. Been reading about hardwired is better. I'm wondering for my situation, is it worth converting over or can I safely use the current socket for L2 charging?

I would go to a hardwired setup. When I was installing a NEMA 6-50 outlet here in MN. I failed the inspection because I didn't have it installed on a circuit with a GFCI breaker. Everything I heard about the GFCI breaker with the NEMA outlet is that they continuously trip inadvertently causing issues with not getting fully charged when you need it. The plug itself wears out and they can heat up and melt or worse cause a fire. The price of one of those breakers is almost the same price as my hardwired Charge Point 48 amp charger that has a builtin protection system making it unnecessary to have the GFCI on the circiut. Very happy with the Charge Point hardwired charger for about 500 bucks.

 

[Mike G]

8 would be awfully weak for a 60A. I'd definitely go at least 6, if not 4, for 60A (as your chart recommends). They used 6 for my 50A.

Remember that an EVSE draws max power continuously for up to 12 hours. That's a lot more stress than a dryer or oven or even A/C that's only on for maybe 30 minutes at a time before shutting off and being able to cool down.

I edited my post after I checked. It is 6 AWG.

 

[johnnycombo]

I did the hardwire in the beginning, not because of what I need now but what I'll need in the future! My thought was go big and do it one time.

 

[Dear_OP]

Thanks for the replies. Lots to think about. If I have nothing, I'd probably look into hardwire as part of the EV-fying the house. Just that I already have an existing 240V plug inside the garage. I think I'll give this route a try... or fry?

Somewhat related question... does the MachE come with charging cable like other EVs? I seem to come across threads where this is an option. That sounds a bit odd.

 

[Peugfan]

OP: So you don't have an EV yet and you have a NEMA-6-50 in your garage? Since the Ford mobile charger has a NEMA 14-50 plug, I would just change the plug to a NEMA 14-50, one of those industrial rated brands as you already have wiring suitable for a 50 amp circuit. Then buy a 40 amp EVSE with a 14-50 plug. A plug in EVSE gives you more flexibility than hard wiring. If you don't yet have a mobile EVSE unit don't buy the Ford brand as they are trouble prone.
I have a JB 40 plug in version on a 50 amp breaker with #6 AWG Romex wire, 20 ft run. I did not install a expensive industrial receptacle, just a standard outlet. However, I took care to properly torque wiring connections and applied a thin coating of dielectric grease on them as well as the plug blades. I've checked temperatures of the receptacle when operating at 40 amps and they are well below skin temperature. I also rarely plug-in/plug-out my EVSE.

Sponsored