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

[PepsidAC]

Hello all,

New owner of a Model Y, first new car in 12 years and we are enjoying the heck out of it! I would like to tweak things a little bit in the house to fully realize the EV experience though.

We have a fairly modern home with a 225 amp box with a 200 amp breaker. Not sure this is relevant to my question below but just for context.

The breaker box reveals a paired 20+20 breaker that are labeled 'Dishwasher' and 'Vacuum' respectively. I tested for this and it is the case.

'Vacuum' refers to a central vacuum that the subdivision homes were built with around 20 years ago, but the previous owner, for whatever reason, has removed the hardware. I have plugged in the garage refrigerator into this (and verified it is a simple 5-15 receptacle) for the past couple of years. I can easily find another receptacle for the fridge within the garage.

Question is, can I use the above outlet, after changing to the appropriate receptacle, to run either 6-15 or 6-20 power to my Model Y? Installing a wall charger is overkill for me, not just because our driving habits (retired, less than 20 miles per day on average, some days are zero) don't require it, but cost is a driver (again, retired) and the location would not be ideal. Plus you can see that I really 'need' a higher charge rate just for the occasional trip.

I am comfortable working in receptacles (changeout etc) but not in panels, although I did do a bit of that many years ago.

While 6-20 would be preferable to 6-15, if it requires running wire then I'll settle for 6-15. I have been using just a 5-15 with 12 amps on the Model Y, so even a 6-15 will more than double my charge and meet 98.2% of my needs .

Thanks in advance for any help.

 

[jcanoe]

You should verify that the wire used on the central vacuum circuit is 12 gauge. If so you can change the receptacle to 5-20 with no issue. To be up to code the receptacle should be a GFCI receptacle (else GFCI breaker.)

Driving 20 miles per day, using the 5-15 receptacle and charging at 120V/12 amps it would take between 4 and 5 hours to add 20 miles of range to the battery. (Even if you stay with using the 5-15 receptacle it should be replaced with a new quality 5-15 receptacle. A GFCI receptacle would bring this up to current code for receptacles used for EV charging.)

To convert the existing 120V/20 amp circuit to 240V/20 amp and change to a 6-20 receptacle you would need to confirm that there were no other 5-15 or 5-20 receptacles on the circuit. You would have to add a 20 amp double pole breaker to the panel and move the wires using the neutral wire (normally white) as the second hot wire and also move the black hot wire and the ground. (No new wires required.) If you are not experienced with working inside home electrical service panels then you should have this work done by a licensed electrician.

 

[PepsidAC]

Pic of twin breaker with vacuum in red.

 

[E90alex]

240v 6-20 circuit would require a double pole breaker so you would need to do some rearranging of the electrical panel if possible.

You can just swap out the outlet for a 120V 5-20 which will be a tiny bit better than standard 5-15.

 

[rwiegand]

If the wire is 12 ga, and if the receptacle is the only thing on the circuit then you can put in a 240 v double pole breaker and a 6-20 receptacle and all will be copacetic. Either the breaker or the receptacle needs to be gfci.

 

[PepsidAC]

Thanks. Considered the 5-20 and may still do so if other plans don't work out.

I need to check for 12 ga wire. It does seem to be the only thing on the circuit but will double check.

Assuming the two things above check out, do you mean I can use the existing double-pole breaker without modification (keeping in mind the other half is still dedicated to the dishwasher)? Yes, planning on a GFCI 6-20 receptacle.

 

[E90alex]

Assuming the two things above check out, do you mean I can use the existing double-pole breaker without modification (keeping in mind the other half is still dedicated to the dishwasher)? Yes, planning on a GFCI 6-20 receptacle.

No, that is a tandem breaker for two 120V circuits. Each pole can be individually turned off.

A double pole breaker supplies one 240v circuit and is typically double the size of a normal breaker with a single switch or two switches permanently connected with a bar to turn on/off both poles at once.

 

[Sophias_dad]

It would be really odd for an electrician to wire a 20 amp breaker with 14 gauge wire, but its always better to check.

Get a zoomed-out picture of your panel.

 

[PepsidAC]

OK I see. As I want to avoid panel work (not lazy, just not confident), this may not work.

Alternate plan: The laundry room is on a shared wall with the garage, and it contains a 14-30 outlet, not in use as the dryer is gas. I thought of tapping into that, passing an extension from laundry to garage (will require making a 3" square hole in the wall) and using that for an even better charge rate. But not sure if this creates a potential hazard owing to passing the wire through the wall? I would use insulation but not sure that would mean anything.

Alternative to alternative: Access the dryer outlet by opening up the garage wall and reinstall the dryer wires into a new receptacle box (effectively reversing the compass direction of the laundry outlet). Downside is this cuts a large amount of drywall (which is fixable of course), but it also wipes out (or strongly reduces) the potential of getting an electric dryer in the future. Plus, code might be an issue.

 

[PepsidAC]

It would be really odd for an electrician to wire a 20 amp breaker with 14 gauge wire, but its always better to check.

Get a zoomed-out picture of your panel.

Happy to oblige, but what are we looking for? So I can make sure it is included in the photo.

 

[Sophias_dad]

Happy to oblige, but what are we looking for? So I can make sure it is included in the photo.

All the breakers, maybe the back of the door so we can see a model number....

 

[Sophias_dad]

OK I see. As I want to avoid panel work (not lazy, just not confident), this may not work.

Alternate plan: The laundry room is on a shared wall with the garage, and it contains a 14-30 outlet, not in use as the dryer is gas. I thought of tapping into that, passing an extension from laundry to garage (will require making a 3" square hole in the wall) and using that for an even better charge rate. But not sure if this creates a potential hazard owing to passing the wire through the wall? I would use insulation but not sure that would mean anything.

Alternative to alternative: Access the dryer outlet by opening up the garage wall and reinstall the dryer wires into a new receptacle box (effectively reversing the compass direction of the laundry outlet). Downside is this cuts a large amount of drywall (which is fixable of course), but it also wipes out (or strongly reduces) the potential of getting an electric dryer in the future. Plus, code might be an issue.

If you want to stay out of the panel, the alternative to alternative plan is best. You aren't likely to go back to an electric dryer.

Making a hole in the wall to pass an extension cord into the garage is a pretty significant no-no. It isn't fire or fume-safe.

 

[Cosmacelf]

Without doing panel work, your only option is to replace the 5-15 receptacle with a 5-20 and thus increase your charge rate by around 42% over using a 5-15. Given that it is on a 20A breaker, it should have the correct gauge of wire to support 20A.

If drywall work doesn't daunt you, then yes, flipping that 14-30 receptacle is relatively straightforward. Do it right, don't use an extension cord.

Either way, you'll have to buy the appropriate Tesla Mobile Connector adapter (either the 5-20 or 14-30).

 

[PepsidAC]

OK I think I have my plan (with one qualifier). Will plan to flip the receptacle around (or use the existing wires in a new receptacle).

My neighbor knows drywall and will help me with the cutout and patch. Once I see the back of the laundry outlet, am I likely to encounter anything crazy? Will it be relatively straightforward to fish out the wire from the old box? (I'm thinking enclosed space and the old box nailed solid to a stud). I will try to mount it a little higher in the wall, so I don't run short of wire.

The qualifier: I read somewhere that some guy did this (not sure if the outlet stayed in the laundry room, I think it did but no difference IMO). He said his dryer plug "melted"! I'd have to think he did something weird. In any case, I'll probably dial down the amps a bit on the app, eg 32 down to say 28.

Cosmacelf, I will still need to use an extension cord. I bought this one: https://www.amazon.com/dp/B0BJZJ7Y6S?psc=1&ref=ppx_yo2ov_dt_b_product_details
Could that create a problem? I'm actually using a short (2 ft) extension right now, on a 5-15 plug.

 

[jcanoe]

OK I think I have my plan (with one qualifier). Will plan to flip the receptacle around (or use the existing wires in a new receptacle).

My neighbor knows drywall and will help me with the cutout and patch. Once I see the back of the laundry outlet, am I likely to encounter anything crazy? Will it be relatively straightforward to fish out the wire from the old box? (I'm thinking enclosed space and the old box nailed solid to a stud). I will try to mount it a little higher in the wall, so I don't run short of wire.

The qualifier: I read somewhere that some guy did this (not sure if the outlet stayed in the laundry room, I think it did but no difference IMO). He said his dryer plug "melted"! I'd have to think he did something weird. In any case, I'll probably dial down the amps a bit on the app, eg 32 down to say 28.

Cosmacelf, I will still need to use an extension cord. I bought this one: https://www.amazon.com/dp/B0BJZJ7Y6S?psc=1&ref=ppx_yo2ov_dt_b_product_details
Could that create a problem? I'm actually using a short (2 ft) extension right now, on a 5-15 plug.

240V dryer circuits are rated for 30 amps. When charging an EV the 80% rule always applies. The maximum amperage while charging on a circuit rated for 30 amps is limited to 80% of 30 amps, a maximum of 24 amps. The Tesla Mobile Connector will automatically limit the charging session to a maximum of 24 amps when you use the Tesla 10-30 power plug adapter (also when you use the Tesla 14-30 plug adapter.) Install a new, quality 30A receptacle. Leave the Tesla Mobile Connector plugged in. Support the Mobile Connector chassis, don't let the Mobile Connector hang supported by the receptacle and the power plug. Tesla sells a Cable Organizer kit that includes a mounting bracket for the Mobile Connector chassis and a hanger for the charging cord. You can find similar kits on Amazon, Etsy and eBay or fashion your own bracket or support.

 

[Cosmacelf]

OK I think I have my plan (with one qualifier). Will plan to flip the receptacle around (or use the existing wires in a new receptacle).

My neighbor knows drywall and will help me with the cutout and patch. Once I see the back of the laundry outlet, am I likely to encounter anything crazy? Will it be relatively straightforward to fish out the wire from the old box? (I'm thinking enclosed space and the old box nailed solid to a stud). I will try to mount it a little higher in the wall, so I don't run short of wire.

The qualifier: I read somewhere that some guy did this (not sure if the outlet stayed in the laundry room, I think it did but no difference IMO). He said his dryer plug "melted"! I'd have to think he did something weird. In any case, I'll probably dial down the amps a bit on the app, eg 32 down to say 28.

Cosmacelf, I will still need to use an extension cord. I bought this one: https://www.amazon.com/dp/B0BJZJ7Y6S?psc=1&ref=ppx_yo2ov_dt_b_product_details
Could that create a problem? I'm actually using a short (2 ft) extension right now, on a 5-15 plug.

1) I hope that 2ft extension cord is rated for 15A? It should be 14 gauge wire, not 16 gauge like a lot of smaller or household extension cords.

2) Yes, that 14-30 extension cord will work. You won’t need to suspend the Mobile Connector (unless you mount it somewhere).

It will probably be easier to get a new box and mount it (nail it) to a stud. Removing a nailed electrical box isn’t the easiest thing in the world. That way you won’t have to drywall patch the laundry room. Just buy a cover for the old box which you put onto the old box after taking out the receptacle.

There are many ways an electrician might have secured the electric wire to your laundry electric box. If you’re lucky, theyll have just used a plastic tab on the box which is a one way friction fit. To free the wire, just bend that tab back into the box. Electricians often will also staple the wire onto the stud. If they did not, then in theory you could cut a double gang box on the other side and fish the wire into the double gang hole, and then you could use a retrofit double gang box and not have to do any drywall repair. Else you’ll have to cut yourself a larger hole and do drywall repair after freeing the wire from the staple (and/or freeing the wire from box connector if they didn’t use a plastic friction tab).

 

[PepsidAC]

Appreciate all your helpful responses! Assuming my neighbor is free, I'll start on this tomorrow.

 

[LostVector]

Appreciate all your helpful responses! Assuming my neighbor is free, I'll start on this tomorrow.

For your first scenario with the 5-15 receptacle on the 20 amp breaker, there should be multiple outlets serviced by that breaker, or else is it not up to code. So you would have to verify the gauge of the wire and then close off all other receptacles before upgrading the candidate receptacle to either 5-20 or 6-20.

For the second scenario with the dryer outlet, you again need to close off the original outlet and move the wires to a new receptacle in the garage. It's unclear why you need the extension cord ... how far of a run are you expecting to need with this charger?

A hardwired wall connector is usually the best option and attempting to save money by using the mobile connector with a plug is really suboptimal as it's slightly less reliable and not even that much cheaper if you do everything up to code (GFCI breakers, high quality outlets, etc).

I'd recommend just summarizing your entire plan here before you do anything as you've (no offense) gotten a few major details with respect to code wrong working through your plan, and it's really better to "measure twice and cut once" with an EVSE install.

 

[PepsidAC]

For your first scenario with the 5-15 receptacle on the 20 amp breaker, there should be multiple outlets serviced by that breaker, or else is it not up to code. So you would have to verify the gauge of the wire and then close off all other receptacles before upgrading the candidate receptacle to either 5-20 or 6-20.

For the second scenario with the dryer outlet, you again need to close off the original outlet and move the wires to a new receptacle in the garage. It's unclear why you need the extension cord ... how far of a run are you expecting to need with this charger?

A hardwired wall connector is usually the best option and attempting to save money by using the mobile connector with a plug is really suboptimal as it's slightly less reliable and not even that much cheaper if you do everything up to code (GFCI breakers, high quality outlets, etc).

I'd recommend just summarizing your entire plan here before you do anything as you've (no offense) gotten a few major details with respect to code wrong working through your plan, and it's really better to "measure twice and cut once" with an EVSE install.

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.

 

[Sophias_dad]

So you would have to verify the gauge of the wire and then close off all other receptacles before upgrading the candidate receptacle to either 5-20 or 6-20.

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.