Converting 5-15 receptacle which is on a 20 amp breaker

[davewill]

I will say is that I think it's a bad idea to use an extension cord for daily charging. If it were my garage, I'd make the effort to run conduit and wire from that box to an outlet box located where I actually wanted to plug the mobile connector in.

A long extension cord is anouther connection to go bad or work loose as you move the cord around. It is also a possible trip hazard if you leave it strung across the garage. It's one thing to use one temporarily to reach an outlet, it's another to depend on one day in and day out, especially at high amperage.

 

[LostVector]

I'm not an electrician by trade, but I'm pretty sure you can mix 5-15 and 5-20 receptacles on the same circuit. Obviously you can't upgrade to 6-20 on one outlet in a chain since its 240 volts.

You can mix and have multiple receptacles as you stated, but only for general purpose devices. Certain devices require a dedicated receptacle/circuit ... of which an EVSE would be one of those.

 

[LostVector]

Thanks, and no offense taken; I'd be the first to admit my own doofusity.

Will try to answer your points:

First, the extension is needed to get to the 'Tesla side' of the garage. The dryer outlet is currently on the 'other car' side. (I have abandoned the 5-20 idea). Then the (20ft) MC will go from the back (house) wall of the garage to the front (street side), almost 20 ft of run when you count the gap between the back wall and the nose of the car. Conveniently, there is a knee wall that runs the length of the garage on that side, so the entire length of the MC rests on that.

And an update: my neighbor had some time today and before you know it, we were done! See below for the near-completed layout. Only the wall texturing remains, followed by the faceplate.

One thing we did not do, as he wanted to move along and his skill level is so far ahead of mine I didn't want to lose that help, is we just turned around the existing box, receptacle, wires and all. It fits pretty well with some shims.

Keeping in mind all y'all's advice to go GFCI, 3 comments:
- Home was built around 2006, SoCal. None of the other outlets in the garage are GFCI and neither are their breakers.
- I understand the code is more recent, so I guess I do need GFCI? That's not a problem as I can go to HD and pick one up. But - this is the only result of the search term "14-30 receptacle GFCI", but nowhere in the product details do I see GFCI noted.

Leviton 30 Amp Industrial Flush Mount Shallow Single Outlet, Black R10-00278-S00 - The Home Depot

Ensure you have an outlet that allows for correct and speedy wiring with the Leviton 30 Amp Industrial Flush Mount Single Power Outlet. This thermoplastic outlet fits Leviton's wide range of 2-3/20 in.

www.homedepot.com

- If you see major issues (I know it's not the most elegant, but I'm referring to safety/code), then please let me know.

View attachment 958548

You do technically need GFCI since this is new work. However, as you noted this requirement is a small update to what would have previously been code compliant.

The GFCI would be on the breaker, not the outlet.

Tesla's wall connector has a 24' cable ... don't know if that's enough for you or if you want the extra expense at this point. In theory the extension cord should be fine, but it does add an extra point of failure. Couple of things to consider would be an in-use cover over the plug instead of a standard wall plate, and some sort of strain relief to prevent the weight of the cord from loosening the connection in the outlet over time.

EDIT: Ah I can think of one more problem. The mobile connector has a temperature sensor in it to detect overheating at the outlet. With an extension cord in the mix, you will only detect overheating at the point where the mobile connector is plugged into the extension cord, and not at the outlet itself. This removes one layer of safety. In fact, note that the warnings at the very start of the Mobile Connector's User Manual explicitly say not to use the Mobile Connector with an extension cord.

 

[Cosmacelf]

Thanks, and no offense taken; I'd be the first to admit my own doofusity.

Will try to answer your points:

First, the extension is needed to get to the 'Tesla side' of the garage. The dryer outlet is currently on the 'other car' side. (I have abandoned the 5-20 idea). Then the (20ft) MC will go from the back (house) wall of the garage to the front (street side), almost 20 ft of run when you count the gap between the back wall and the nose of the car. Conveniently, there is a knee wall that runs the length of the garage on that side, so the entire length of the MC rests on that.

And an update: my neighbor had some time today and before you know it, we were done! See below for the near-completed layout. Only the wall texturing remains, followed by the faceplate.

One thing we did not do, as he wanted to move along and his skill level is so far ahead of mine I didn't want to lose that help, is we just turned around the existing box, receptacle, wires and all. It fits pretty well with some shims.

Keeping in mind all y'all's advice to go GFCI, 3 comments:
- Home was built around 2006, SoCal. None of the other outlets in the garage are GFCI and neither are their breakers.
- I understand the code is more recent, so I guess I do need GFCI? That's not a problem as I can go to HD and pick one up. But - this is the only result of the search term "14-30 receptacle GFCI", but nowhere in the product details do I see GFCI noted.

Leviton 30 Amp Industrial Flush Mount Shallow Single Outlet, Black R10-00278-S00 - The Home Depot

Ensure you have an outlet that allows for correct and speedy wiring with the Leviton 30 Amp Industrial Flush Mount Single Power Outlet. This thermoplastic outlet fits Leviton's wide range of 2-3/20 in.

www.homedepot.com

- If you see major issues (I know it's not the most elegant, but I'm referring to safety/code), then please let me know.

View attachment 958548

Good stuff. I don’t think they make 14-30 GFCI receptacles, so you’d have to get a 30A GFCI breaker. The only reason for a GFCI is to prevent a shock hazard when you unplug a heavy duty plug from a receptacle. It isn’t a fire risk mitigation measure, just a shock hazard measure. If you’re ok with that (Be smart and not dumb when pulling out plugs from receptacles, don’t grip around the plug and contact the blades!), then leave it be. Or pay $80 for a GFCI breaker and do some panel work to install it (it’s a bit finicky since you have to route the white wire from the breaker to the neutral bus bar).

 

[EbS-P]

Im going to recommend hardwired chargers on a dedicated 240v branch circuit. Even it’d it’s only 20A.

Reasons, has no need for gfci breaker saves lots of money. No need to ever worry about extension cords. No need to worry about physical wear on a receptacle.

I used an existing 20A circuit with 12-2 plus ground wire that used to power the house well. With a j box, conduit, double pole 20 amp breaker and gen 3 wall charger I was all set.