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While not a licensed electrician, I'm concurred about the fill rate of your existing conduit. 60 Amps at 70 ft will require 4 AWG THWN wire for an underground run inside conduit.
Why do you keep saying 4 gauge? 6 gauge wire in conduit is rated fine for up to 65A. Are you thinking because of 70 feet being a long run? It's not that long, and code doesn't require oversizing for that. Does it being underground change the requirement in some way I'm not aware of?How are you going to get 60 Amps (4 AWG) inside a 3/4" conduit? Conduit Fill Table.
Why do you keep saying 4 gauge? 6 gauge wire in conduit is rated fine for up to 65A. Are you thinking because of 70 feet being a long run? It's not that long, and code doesn't require oversizing for that. Does it being underground change the requirement in some way I'm not aware of?
I was using wire size calculator 1 and 2 and both say 60 Amps at 240V at 70 Ft should be 4 AWG. Fill calculator says 6 AWG is as large as you can go in 3/4 EMT, so that drops to 55 Amps max (thus 50 Amps is the highest you could go practically).
THWN (water-resistant) is specified for underground in conduit so that was what I was using as the specified cable. .Perhaps a specific THWN cable might allow for more heat? Where were you seeing 6 AWG could carry 65A? I'd love to find something that would allow for more amperage.
You are correct that 48 Amps would be the I variable in the calculation if the EVSE were the only device on the circuit. However in this setting, there could be other loads on the 120V/20Amp leg.
FWIW, I was taught to use the tripping load when calculating the wire size since the circuit could operate up to that level safely.
no. It’s 48 amps max no matter what. In America, 240v is just two 120v legs out of phase with each other so that the potential across them is 240. The 120v circuit would be just one one leg of the 240, but you arn’t allowed to draw more than 80 percent total.
To select the size of the wire, yes. For voltage drop calculation, nope.
Earlier this year, I had two #4 75-foot lines run from my 200A panel to my garage, each terminated in separate 14-50 NEMA connectors. Each line was run inside separate 1" conduits. The total cost by the licensed electrician was about $3200; note that this was in California.
For now, each line is supported by a 50A breaker (I'm using a Juicebox 40 for 1 outlet and the Tesla mobile charger for the other outlet); #4 lines provide me the option to upgrade to 60A breakers and hardwire a 48A Tesla Wall Connector in the future.
Just so I understand, you technically could have used #6 wire and still go up to 60A eventually, is that correct?
Oh, other end of the telescope. You are starting from the perspective of trying to prevent voltage drop. And I do see that in the calculators you were using. Voltage drop calculations are a recommendation, but not a requirement in NEC, and for EVSEs, they don't matter much if they have some voltage drop. If it were a 200 or 300 foot run, I would lean more toward doing this drop calculation, because it could be getting pretty bad, though.I was using wire size calculator 1 and 2 and both say 60 Amps at 240V at 70 Ft should be 4 AWG. Fill calculator says 6 AWG is as large as you can go in 3/4 EMT, so that drops to 55 Amps max (thus 50 Amps is the highest you could go practically).
THWN (water-resistant) is specified for underground in conduit so that was what I was using as the specified cable. .Perhaps a specific THWN cable might allow for more heat? Where were you seeing 6 AWG could carry 65A? I'd love to find something that would allow for more amperage.
Technically, these are the guidelines for wire gauge and amperage:
6/3 Romex = 55A
4/3 Romex = 70A
6 gauge wire is enough to handle a 48A charger (60A breaker, if not using up to 60A). I had 4 gauge wire installed for margin.
Currently I have a 120v 20amp line running from our house to a detached garage through a 3/4" conduit that is about 60-70' in length. The distance from the panel to where the conduit leaves the house is about 50' through a drop ceiling in the basement.
I had an electrician come by today and he said he could run a dedicated 240v 60amp line to the garage using the same route and conduit. He would just have to pull new wire through the conduit. In the garage he would install a sub-panel to provide service to the current circuits in the garage (lights, outlets and garage door opener) with 120v 20amp and then install a dedicated 14-30 Nema outlet for the Tesla. He would install a ground rod near the garage as well.
He wants $2,300 to do this. Seems like a lot to me. I am in northern NJ. For those of you who have done similar installs, do you think this is a fair price? Anyone have a recommendation for an electrician in northern NJ? Thanks.
You: It's for my new Tesla!I would get some additional quotes my first quote for the standard Tesla wall connector was $1350. My second quote was $425. How can it be so different. My opinion is that the electricians think if you own a Tesla you are a millionaire!! Good luck
Currently I have a 120v 20amp line running from our house to a detached garage through a 3/4" conduit that is about 60-70' in length. The distance from the panel to where the conduit leaves the house is about 50' through a drop ceiling in the basement.
I had an electrician come by today and he said he could run a dedicated 240v 60amp line to the garage using the same route and conduit...
Currently I have a 120v 20amp line running from our house to a detached garage through a 3/4" conduit that is about 60-70' in length. The distance from the panel to where the conduit leaves the house is about 50' through a drop ceiling in the basement.
I had an electrician come by today and he said he could run a dedicated 240v 60amp line to the garage using the same route and conduit. He would just have to pull new wire through the conduit. In the garage he would install a sub-panel to provide service to the current...
I ran three 60 amp circuits to my garage -- 120 feet from panel to 2 gen 2 chargers and 1 gen 3 charger. Remember the cable must be copper which is more expensive than aluminum. Most people do not pay attention to this - however it can overheat and cause a fire if you do not install copper. Additionally - I have 3 general 60amp load sheds. price $3400 with installation of chargers (I bought the chargers) - he installed the cabling and the breakers. I charge at 48amp - max for model Y and 3. I have 2 Teslas currently with cybertruck coming - you may ask wh 3? I plan to never own an ICE vehicle again and I was renovating the garage. see my profile pic. Also -- you must have a permit for this installation. Given your installation to an external structure involving conduit - panel - grounding rod - and - most towns in NJ require a local circuit cutoff switch for 60 amp and above - I believe your price may be slightly on the high side - but if it includes permits and copper cable as well as cutoff - I think its fine. Get 3 quotes and you will know what's competitive in your area. Im from Manalapan in central/south jersey (exit 8)