EV charging plug 6-50 vs. 14-50

[rjacobs]

Going to wire up and install a plug for an EV charger for a plug in hybrid I just bought. Dont need to go overkill as the internal charger only runs 3.7kw, but am thinking multi purpose...

50a non GFCI breaker(again its overkill as I will likely only use 16a on 220v anyway and non-GFCI because i may use it as a generator input)

Thinking triple/quad purpose which is what has me contemplating which plug to use...

Welder use pushes me towards 6-50

Generator input feed(would use an interconnect) I believe pushes me to a 14-50

EV charger can be ordered with either 6-50 or 14-50 plug...

Temp plug in for an RV which I believe all are 14-50's.

I believe for the welder I could simply get a 14-50 to 6-50 adapter and solve that small issue.

So 14-50?

6g THHN...

Southwire (By-the-Foot) 6/3 Stranded Romex SIMpull CU NM-B W/G Wire 63950099 - The Home Depot

Wire residential indoor branch circuits for outlets, switches and other loads with Southwire Romex SIMpull Type NM-B Cable. SlikQuik jacket allows for 50% reduction in pulling force for easier installation.

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Looking at receptacle gang boxes, I can surface mount or probably flush mount a metal box. I dont think "old construction" plastic boxes are sturdy enough for 14-50 plugs and the cords associated with them.

 

[mike93lx]

There is no way to use this for input and output without it costing way more than another plug, so forget the generator aspect

Is it in a good spot for a welder to connect? The welder feed can be downsized, so if another location makes more sense for that, keep it separate.

14-50 is likely what I will do in my garage, but I'll also likely add a 6-50 on the same circuit for a welder

 

[u2slow]

EMT to a healthy-sized metal box. Pull in minimum conductor size and count. Change it up if your needs increase.

Generator hookup doesn't make sense unless it the good ol' suicide cord approach.

 

[dave*99]

A generator inlet must be on an interlock breaker such that the main and the generator breakers can not be be on at the same time..
The EV receptacle will be on a normal breaker.
Can't mix the two.

 

[rjacobs]

Can't mix the two.

"legally"

 

[rjacobs]

the good ol' suicide cord approach.

basically yes

 

[jeepxj]

14-50 for sure if you're going outlets. if it was hardwired EVSEs then 2 hots and a ground is plenty.

some things to consider:

6/3 romex is only good to 55a. if you ever go hardwire charger a very popular size runs a 60a breaker. that gives you 48a charging max. most chargers will allow you to dial it down to 40a which is still more than enough for nearly anyone. Down the line however if you run a dual car charger off that line the extra 8a couldn't hurt.

#6 THHN in conduit will get you over that 6a rating.

 

[rjacobs]

There is no way to use this for input and output without it costing way more than another plug, so forget the generator aspect

Is it in a good spot for a welder to connect? The welder feed can be downsized, so if another location makes more sense for that, keep it separate.

14-50 is likely what I will do in my garage, but I'll also likely add a 6-50 on the same circuit for a welder

It can be used for in and out, just not "legally"...

I have a 50ft welder extension cable, might only be 25 feet actually, so the location is ok. My garage is ~35 feet across and I dont expect I would ever be welding against the far wall.

 

[rjacobs]

14-50 for sure if you're going outlets. if it was hardwired EVSEs then 2 hots and a ground is plenty.

some things to consider:

6/3 romex is only good to 55a. if you ever go hardwire charger a very popular size runs a 60a breaker. that gives you 48a charging max. most chargers will allow you to dial it down to 40a which is still more than enough for nearly anyone. Down the line however if you run a dual car charger off that line the extra 8a couldn't hurt.

#6 THHN in conduit will get you over that 6a rating.

Whatever I buy will max out at 40a I believe. It seems most boxes these days are 16, 24, 32, 40a. It seems the Tesla is about the only one at 48a right now. I'm only going to use 16a as thats all the car will take so even #6 romex is way overkill for me.

 

[mike93lx]

Forget "legal" (fyi, electrical code isn't law). Suicide cords are stupid. Simple as that. Doing it right is neither hard, nor expensive.

 

[jeepxj]

Whatever I buy will max out at 40a I believe. It seems most boxes these days are 16, 24, 32, 40a. It seems the Tesla is about the only one at 48a right now. I'm only going to use 16a as thats all the car will take so even #6 romex is way overkill for me.

Fair enough. even with 40a you will have a ton of power for charging. easily over 100kwh a night.

 

[rjacobs]

Fair enough. even with 40a you will have a ton of power for charging. easily over 100kwh a night.

Its a BMW 330E. Only has a 12kw battery. The 110v plugin it came with is fine for overnight charging, but would love to be able to charge fully in 3 hours so if I go run errands in the morning I can come home for lunch and a nap, plug in the car, and when I go back out in the evening its charged again... Only goes 25 miles on a charge. At 8.4c per KW it costs me $1 to charge the car. Gas engine alone is rated at 37mpg and I'm paying ~$3 right now.

This ******* hybrid system is smart though. If you use the nav(which I have zero real use for 98% of the time) it will optimize the gas vs. electric, supposedly knows where the hills are for regen, etc... I need to make my normal drive to work a few times in different modes and see whats best, but so far the "adaptive" or "intelligent" something like that seems to be doing ok. Did EV the 4 miles to the highway, gas for ~30 miles, then back to EV for the 4 miles off the highway to the parking lot. Same for the way home and pulled in the garage with ~2 miles of EV range left. Got 57mpg combined round trip to work the other day. Prius I traded in would do 54-55 on the same route.

 

[u2slow]

For a mixed 120/240v generator feed of any sort, you want a neutral in the conduit.

 

[wyliesdiesels]

dont bother doing an inlet and outlet all at the same time... c'mon man... do it right...

 

[89MustangGX]

Generator input feed(would use an interconnect) I believe pushes me to a 14-50

"legally"

It can be used for in and out, just not "legally"...

Not just a matter of legal or not, the whole purpose of the interlock is to physically keep you from having both on at the same time. If you are going to defeat that or you make it easy enough to defeat, you might as well not even install it at all. What would be the point?

 

[rjacobs]

Good news...

The spare 50A breaker in my box I planned to use is a GFCI which I cant backfeed the panel through from a generator. But I can use it for all other functions. So ill run a 14-50 off of that and use a conversion cord for a welder(looks like it should work and not trip the GFCI from my limited research). AND while I have the panel open ill install a normal 50a breaker with an interlock kit and an actual generator input plug.

So for all of you "your gonna burn your house down and electrocute yourself" folks... crisis averted...

 

[beemerphile]

Forget "legal" (fyi, electrical code isn't law).

...until adopted by an AHJ, then it is indeed enforceable. Many adopt NFPA 110 for generator safety. Even if a homeowner avoids a required inspection, the adopted codes are still enforceable in my area by Code Enforcement. Georgia state law, probably like many others, states that the codes adopted by the state are enforceable whether the work was inspected or not. You can bet that if you injure someone with a suicide setup that you will be prosecuted (unless it is you who are the unfortunate victim). In that case they may simply mention at your wake that the dearly departed was an idiot.

Suicide cords are stupid. Simple as that.

If the stupid only endangered themselves, it may have some Darwinian benefit. Unfortunately they have a wider reach.

 

[alfredeneuman]

6/3 romex is only good to 55a.

There are no 55A breakers so as long as the load is under 55A, you're allowed to increase the breaker size to the next standard size (60A)

 

[dcg9381]

14-50R for me at the house. I have a 10-12kw generator with a 14-50R on it also... It's kinda our "standard" 240v outlet anyway since we have RVs and RV owning guests.

 

[wyliesdiesels]

14-50R for me at the house. I have a 10-12kw generator with a 14-50R on it also... It's kinda our "standard" 240v outlet anyway since we have RVs and RV owning guests.

So youre using it for both the generator and the RVs?

 

[dcg9381]

So youre using it for both the generator and the RVs?

No. The house has full 20kw backup off an automatic ATS. I don't do "suicide cords".

The shop is "manual transfer" (with an interlock on the shop feed and solar). If our power goes down and we need power to the shop, I have to lug the generator out and use the appropriate Generator power inlet at the shop.

It's just that my shop generator has (on it) a 14-50R. When we buy an EV the EVSE (charing station) will likely be setup on a 14-50P and set to <48A continuous. Largely because these are our "standard" 240V outlet - I have several of them around the shop.