# Correct wire size??



## SuperM1952 (4 mo ago)

My daughter has a correct 220 volt receptacle in her garage. The previous owner of the home wired this with a 10 gauge 4 conductor wire for some sort of machinery (woodworking or?). It is 30 feet from panel box and it is protected by a single throw 20 amp 220 breaker. Where am I as far as charging her Model three. Can I charge it with whats there or as I suppose upgrade to what? Thanks for all the help up front Skip.


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## NR4P (Jul 14, 2018)

Send a photo of the receptacle so we know what kind of plug is required and we can see if Tesla offers the plug. That is the safe method


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## Rub"Y" (4 mo ago)

With 10-4 wire you could change the breaker to a 40 amp and charge at 32 amps. With a 20 amp breaker you shouldn't charge at more than 16 amps ( 80% of breaker rating )


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## SuperM1952 (4 mo ago)

NR4P said:


> Send a photo of the receptacle so we know what kind of plug is required and we can see if Tesla offers the plug. That is the safe method


Already got the plug directly from Tesla, It all fits perfect. The more I read it looks like it has to be a number 6 gauge wire and a 60 amp breaker. I can take the receptacle box off the ceiling (previous owner) and move it to the wall and that would cut the run down to 15/20 feet. I am not at her house so I can't get a pic.


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## SuperM1952 (4 mo ago)

Rub"Y" said:


> With 10-4 wire you could change the breaker to a 40 amp and charge at 32 amps. With a 20 amp breaker you shouldn't charge at more than 16 amps ( 80% of breaker rating )


So changing the square D breaker to a 40 amp breaker and a charge rate of 32 amps is safe. the wire is jacketed and run through PVC conduit. Since I am DAD GAS,LOL, it seems that you are alluding to the fact that onecan select the charge rate of the tesla somewhere in the computer??? Sorry but I am Tesla ignorant. but.....I think they are the bomb My pockets during retirement are just not as deep as my daughters. Thanks again Skip


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## SuperM1952 (4 mo ago)

SuperM1952 said:


> So changing the square D breaker to a 40 amp breaker and a charge rate of 32 amps is safe. the wire is jacketed and run through PVC conduit. Since I am DAD GAS,LOL, it seems that you are alluding to the fact that onecan select the charge rate of the tesla somewhere in the computer??? Sorry but I am Tesla ignorant. but.....I think they are the bomb My pockets during retirement are just not as deep as my daughters. Thanks again Skip


So charging at the 32 amp rate what kind of charge will that give me overnite? I know it will be much greater then the 110/15. She is looking for something that will give her more charge over the 10/12 hour down time while she is home from work.


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## shareef777 (Mar 10, 2019)

SuperM1952 said:


> Already got the plug directly from Tesla, It all fits perfect. The more I read it looks like it has to be a number 6 gauge wire and a 60 amp breaker. I can take the receptacle box off the ceiling (previous owner) and move it to the wall and that would cut the run down to 15/20 feet. I am not at her house so I can't get a pic.


It doesn't HAVE to be #6/60A. That's what it COULD be to get the absolute fastest charging the vehicle is capable of at home. You can just choose to charge at the slower rate. If you're CERTAIN the wiring in the walls between the receptacle and breaker is #10, you can up the breaker to 30A (along with the appropriate receptacle, and charge slightly faster.

Keep in mind that swapping #10 for #6 wire is easier said than done (especially if the conduit isn't sized to support the larger gauge wire).


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## shareef777 (Mar 10, 2019)

SuperM1952 said:


> So charging at the 32 amp rate what kind of charge will that give me overnite? I know it will be much greater then the 110/15. She is looking for something that will give her more charge over the 10/12 hour down time while she is home from work.


The computer will auto choose the charging rate (giving you the option to lower it in-vehicle) based on the plug you're using in the mobile connector.









Gen 2 NEMA Adapters


Use a variety of household outlets to charge your Tesla with a Gen 2 NEMA Adapter. Simply attach the appropriate adapter to your Mobile Connector, plug into the corresponding outlet and begin charging. Adapter Max Distance Gained Per Hour of Charge Model S Model 3 Model X Model Y 5-15 3...




shop.tesla.com


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## SuperM1952 (4 mo ago)

shareef777 said:


> The computer will auto choose the charging rate (giving you the option to lower it in-vehicle) based on the plug you're using in the mobile connector.
> 
> 
> 
> ...


This is what I ordered and received
Gen 2 NEMA Adapters
14-50
Quantity: 1


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## JasonF (Oct 26, 2018)

SuperM1952 said:


> My daughter has a correct 220 volt receptacle in her garage. The previous owner of the home wired this with a 10 gauge 4 conductor wire for some sort of machinery (woodworking or?). It is 30 feet from panel box and it is protected by a single throw 20 amp 220 breaker. Where am I as far as charging her Model three. Can I charge it with whats there or as I suppose upgrade to what? Thanks for all the help up front Skip.


I looked it up, code recommends 30 amp maximum for 10 gauge. So it's basically a dryer supply, and should have a 14-30 outlet (4 prong) on it if it has a separate ground, or a 10-30 (3-prong) if it doesn't. Tesla sells both kinds of plug heads for the Mobile Connector.

You shouldn't need to push for more amps, 30 is plenty for charging, it will get (according to Tesla) 17 miles per hour of charge, and charge 24 amps at 240 volts.


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## Rub"Y" (4 mo ago)

Specified nominal amperage for 10 gauge is 30 amp with 20% safety zone. So I'm going to be charging at 32 amps at first and I 'll monitor the wire temperature so it remains under the maximum specs. This should give me a 25mph charge, which is plenty. If I see that I don't need this much I will lower the charge rate.


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## shareef777 (Mar 10, 2019)

SuperM1952 said:


> This is what I ordered and received
> Gen 2 NEMA Adapters
> 14-50
> Quantity: 1


You def can't just update the receptacle. You'll need to re-run the wires and breaker to support the 50A that the vehicle will be able to pull.


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## Rub"Y" (4 mo ago)

You can't draw more than 32 amps through that Tesla home cable.


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## SuperM1952 (4 mo ago)

So to summarize: On the 14 50 adapter I purchased that fits into the 4 prong adapter I can
1. On the 10 gauge 4 wire circuit I can put a 30 amp circuit breaker and set the charge rate at 80% of the breaker which would be a charge rate of 24 amps.
2. Replace the breaker and go to a 40 amp breaker and charge at a 32 amp rate on 10 gauge wire.
3. Replace entire circuit with a 6 gauge run, proper sizing of PVC conduit, dbl. 60 amp breaker, and have a charge rate of 32 amps regulated by the Tesla mobile connector.

Thankyou all for the great responses. I will proceed in numerical order, or the easiest to the hardest, least expensive to the more expensive. Thanks to all Skip


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## Rub"Y" (4 mo ago)

24 amps will give you approximately 20-21 miles /h of charge, so over 200 miles over night with 10 hours of charging. That 3rd option is not recommended if you will still be using the Tesla home cable.( Overkill )


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## JasonF (Oct 26, 2018)

SuperM1952 said:


> 2. Replace the breaker and go to a 40 amp breaker and charge at a 32 amp rate on 10 gauge wire.


Don't do that, the 10 gauge wire will be hot all the time, which is not good for its insulation or the connections. Car charging puts a lot of stress on the wiring, you want to give it every reason to keep as cool as possible.


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## Rub"Y" (4 mo ago)

JasonF said:


> Don't do that, the 10 gauge wire will be hot all the time, which is not good for its insulation or the connections. Car charging puts a lot of stress on the wiring, you want to
> give it every reason to keep as cool as possible.


By the looks of the Tesla home cable it is smaller than 10 gauge. So 10 gauge wire wouldn't be the weakess link. I will measure the temperature of both cables since I have this setup and report back as soon as I get my 14-50 plug.









The wire that plugs into the 14-50 outlet is even smaller as you can see from the picture in post #9


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## FRC (Aug 4, 2018)

You need the advice of a professional electrician. It's clear from your questions that you know just enough to get yourself in trouble (I would put myself in that same boat). And relying on the help of strangers here is a roll of the dice; maybe it works out fine, maybe your daughter's house is a pile of ashes tomorrow.


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## JasonF (Oct 26, 2018)

Rub"Y" said:


> By the looks of the Tesla home cable it is smaller than 10 gauge. So 10 gauge wire wouldn't be the weakess link. I will measure the temperature of both cables since I have this setup and report back as soon as I get my 14-50 plug.


And none of those wires stay cold. That was the reason I suggested not upgrading 10 gauge wire to 40 amps. It can handle it, but it's going to run hot all the time, which is not really a good idea inside of walls or around screw connections.


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## Rub"Y" (4 mo ago)

As promised I received my 14-50 today, when I got back from Bedford picking up my daughter's model "Y", black on black. It's gorgeous when clean.










Did the test and checked for heat emanated from cables after 15 minutes.

Temperature in garage was 61°F ( 16°C )
1. The cable from the car connector to the Tesla controller 71°F ( 22°C )
2. Tesla controller box to 14-50 plug ( Cable I received today ) 77°F ( 25°C )
3. 10-4 cable from receptacle to breaker 66°F ( 19°C )
4. Circuit breaker 71°F ( 22°C )

So I would share with you that it is very safe to charge with this set-up and @ 48Kms/hr ( 30m/hr ) it is plenty to charge your "Y" over night even if it is down to 10%. 8 hours will give you 384 kms ( 239 miles ) of added range.

If cables reach 140°F ( 60°C ) then it would approach the danger zone and my readings were way bellow that. So I'm confident with this set-up and will not modify anything else.


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## Rub"Y" (4 mo ago)

For those following this thread....I said I would post this here so true to my word here it is.

Just came from my daughter's house where I installed her Tesla wall mount unit in her garage near the panel .


















Wired it to a 60 amp Schneider breaker with 6 gauge 3 wire cable. ( 6 gauge is overkill but that's what the Tesla guide recommends ) Pretty sure it isn't 6 gauge in the Tesla cable going to the car.










After charging at 48 amps for 1/2 an hour.

1. Tesla cable going to the car was at 31°C ( 88°F )
2. 6 gauge was pretty much at room temperature 19°C ( 66°F )
3. 60 amp breaker housing 37°C ( 99°F )

Total Cost
1. Schneider breaker 60 amp $75 Cdn
2. Two meters of 6 gauge wire $25 Cdn
3. One panel wire collar $3 Cdn
4. One bandaid
5. Hourly rate dirt cheap, for a total of $125 Cdn with taxes. ( $94 USd )

Son-in-law decided that 40 amp charge rate would be sufficient for his needs, which I totally agreed with.

I charge at 32 and more than enough.


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## JasonF (Oct 26, 2018)

Is it just the photo, or are the breakers on the right side actually sloping downward a little bit? 

The breaker getting warm is normal unless it's painful to touch (the plastic part, obviously, the metal part will always be painful to touch!). The extra careful part of me says go back after a few days of charging and re-tighten all of the lugs to make sure wire expansion doesn't cause some slack.


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## Rub"Y" (4 mo ago)

Just the picture that was taken up close with my cell phone. Not the best lens. I was planning to go back next week even if I put ferrules on the stranded wire. I even tighten the screws on the main breaker, house is 4 years old. Doing the live side is always hairy. You have to be so careful. The electrician that did their panel must have been an apprentice, I would never approve his work. What a mess.


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## SimonMatthews (Apr 20, 2018)

SuperM1952 said:


> So charging at the 32 amp rate what kind of charge will that give me overnite? I know it will be much greater then the 110/15. She is looking for something that will give her more charge over the 10/12 hour down time while she is home from work.


You can select the charge rate and the car will remember it for that GPS location. The setting is on the charging screen.


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## JasonF (Oct 26, 2018)

Rub"Y" said:


> Just the picture that was taken up close with my cell phone. Not the best lens. I was planning to go back next week even if I put ferrules on the stranded wire. I even tighten the screws on the main breaker, house is 4 years old. Doing the live side is always hairy. You have to be so careful. The electrician that did their panel must have been an apprentice, I would never approve his work. What a mess.


Get a good insulated screwdriver (one that has plastic covering almost down to the end) and it will be really easy. Even if you slip the exposed metal isn't enough to short anything.


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## Rub"Y" (4 mo ago)

The main breaker had Allen screws. I had a T handle to which I added 2 layers of shrinkable tubing almost to the tip but was still a bit apprehensive. A 110 shock tickles put a 240 kinda hurts a bit. lol


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## JasonF (Oct 26, 2018)

Rub"Y" said:


> The main breaker had Allen screws. I had a T handle to which I added 2 layers of shrinkable tubing almost to the tip but was still a bit apprehensive. A 110 shock tickles put a 240 kinda hurts a bit. lol


Double protection doesn’t hurt. I usually wear mechanics gloves while working with electricity. Great extra protection - once I discovered in a condo that the neutrals across all circuits in a room were bundled together when I tried to re-twist the bundle in a light fixture while the breaker for it was definitely off, and they sparked at me. I didn’t feel it through the gloves, so I just worked faster before they became damaged.

But you still have to be careful about slipping badly enough to touch a live phase to the box and ground it, that can do some serious damage.

There are things like these that are extra safe because they’re insulated and easier to control:






Amazon.com: Wiha 32366 2.5-8 Insulated Hex Metric Screwdriver Set, 6-Piece : Sports & Outdoors


Buy Wiha 32366 2.5-8 Insulated Hex Metric Screwdriver Set, 6-Piece: Swimming - Amazon.com ✓ FREE DELIVERY possible on eligible purchases



www.amazon.com


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## Klaus-rf (Mar 6, 2019)

When you're checking tightness on the breaker-to-wire screws, ALWAYS switch offthe breaker so the screws are no longer powered.


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## Rub"Y" (4 mo ago)

Yes, but I was talking about the live side of the main breaker.


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## Madmolecule (Oct 8, 2018)




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