Garage sub panel gut check

[smokey0066]

I just recently purchased a Tesla and I wanted to installed the wall charger in my garage. Spoke with an electrician and then I was asking them to put some extra receptacles in and then it got “complicated” as he put it. I didn’t actually get a quote back yet but I started doing a lot of reading, youtube watching, and talking to some coworkers trying to understand why it got complicated. That got me thinking I could probably put in a sub panel in the garage and wire up most of the garage myself.

What I’d like to put in are 1 wall charger and rough in for a second one. Along the perimeter I'd like to add some 120v 20a receptacles (probably 1 circuit for each side of the garage) and possibly a 240v in the corner for a future air compressor while I’m in there – not sure plug or amperage rating that I need (so please correct my shopping list if I'm mistaken). I’ll also run some ethernet to the garage while I’m in there. There is only 1 circuit feeding my garage right now which are 3x overhead light, 2x ceiling receptable for garage door opener, 1x wall receptacle which everything in the garage is plugged into. I will trip the breaker when doing a lot of work outside so I need to be mindful of the load I use right now.

Our area follows the 2020 NEC codes. My house has a 200amp CH panel on the opposite side of the garage so it’ll be a longer run. My basement and garage are both unfinished except for the shared wall which is insulated and sheet rocked on the garage side. The run from my main panel to the sub would be about 75ft depending on exact placement of the panel and wire routing. Then from the sub to the wall charger will be maybe 40ft. I'm trying to keep everything in the walls which could make my life miserable....

Shopping list:
CH 100amp breaker
SER 1-1-1-3 copper feeding the sub panel

Eaton CH subpanel Model: CHP22B100V29
CH 2 pole 60amp breaker
NM-B 4/3 copper for the tesla charger
CH 1 pole 20amp AFCI/GFCI breaker
NM-B 12/2 for the rest of the garage
CH 2 pole 30amp breaker
NM-B 8/3 for the 240 – future air compressor?

I went with the CH subpanel to match my main panel which is also a CH panel. I know I need some TR receptacles, boxes, staples, clamps for the wires going into the panels. Will probably have a bunch of trips to the store while I’m working.

Couple of questions:
Have I missed anything in my planning and shopping list?
I'm a little bit worried about the SER and 4/3 wires, will I have a horrible time running them?
Do I need any special sealant when I’m going between the house/garage and through the top plate in the garage walls?
Should I wire anything else in “while I’m in there.. “?
When I’m wiring for the rough I know I clamp the wires in the boxes and leave the 6” out and the ground pigtailed but do I connect the other end to the breaker? Or do I just leave that end taped off inside the panel but not connected yet?

TIA if you've made it through my long post. First time doing electrical work and its a lot to take in but also very interesting.

 

[Stuff]

1. Do a load calc to verify that your main panel doesn't need upgraded
2. Verify that this is an attached garage
3. A Tesla Wall Connector is an EVSE, not a charger. You will be chastised as the charger is part of the vehicle for level 1 and 2 charging.
4. These days SER 3awg copper is technically good for 100 amps. 4awg for 85 amps on a 90 amp breaker. Any option for conduit?
5. The Tesla Wall Connector doesn't need a neutral so you can use 4/2 (two hots and a ground)
6. Future air compressor would be 10 gauge if 30 amp breaker. 10/2 as most don't need neutrals. Many only need 15 amps at 240v.

 

[smokey0066]

1. Do a load calc to verify that your main panel doesn't need upgraded
2. Verify that this is an attached garage
3. A Tesla Wall Connector is an EVSE, not a charger. You will be chastised as the charger is part of the vehicle for level 1 and 2 charging.
4. These days SER 3awg copper is technically good for 100 amps. 4awg for 85 amps on a 90 amp breaker. Any option for conduit?
5. The Tesla Wall Connector doesn't need a neutral so you can use 4/2 (two hots and a ground)
6. Future air compressor would be 10 gauge if 30 amp breaker. 10/2 as most don't need neutrals. Many only need 15 amps at 240v.

1. I haven't performed a load calculation, I'll look into it.
2. It is an attached garage with a half finished shared wall between the two.
3. EVSE, got it.
4. I went with the #1 because Southwire voltage drop calculator recommended it based on my inputs. I would prefer not to run conduit but I can if its a better option. I looked at the blue conduit and thhn wires but figured the SER would be easier as its all in one.
5. I wasn't able to find 4/2 Romex.
6. Thanks. Maybe I'll defer this circuit until I purchase the air compressor. I'll have easy access to run the circuit when the time comes.

 

[mm08822]

Make sure of the conductor requirements for the Tesla Wall Connector. Two I did were copper only connections.

Sub-panel in garage option provides the easiest way to add in other circuits down the road.
It also multi-purposes the use and cost of what may have otherwise been a dedicated feeder to the EVSE.

 

[smokey0066]

Make sure of the conductor requirements for the Tesla Wall Connector. Two I did were copper only connections.

Sub-panel in garage option provides the easiest way to add in other circuits down the road.
It also multi-purposes the use and cost of what may have otherwise been a dedicated feeder to the EVSE.

Yup the NM-B 4/3 copper is for the Tesla EVSE. Its in transit right now but based on what I've read online it should be copper only going to it.

 

[mm08822]

Yup the NM-B 4/3 copper is for the Tesla EVSE. Its in transit right now but based on what I've read online it should be copper only going to it.

You probably only needed 4-2 if hard-wired.

 

[smokey0066]

You probably only needed 4-2 if hard-wired.

Thank you - I wasn't able to find 4/2 romex so I figured I'll just cap off the neutral in the EVSE. It'll be available if it gets used for something else in the future? I was trying to avoid conduit with thhn.

 

[Stuff]

Right, no 4/2 NM so instead there is 4/2 SE. Since it is SE you can go with the 75º column and use 6/2 as well so a double bonus.

 

[smokey0066]

1. Do a load calc to verify that your main panel doesn't need upgraded
2. Verify that this is an attached garage
3. A Tesla Wall Connector is an EVSE, not a charger. You will be chastised as the charger is part of the vehicle for level 1 and 2 charging.
4. These days SER 3awg copper is technically good for 100 amps. 4awg for 85 amps on a 90 amp breaker. Any option for conduit?
5. The Tesla Wall Connector doesn't need a neutral so you can use 4/2 (two hots and a ground)
6. Future air compressor would be 10 gauge if 30 amp breaker. 10/2 as most don't need neutrals. Many only need 15 amps at 240v.

I ran through the NEC Standard Electrical Load Calc worksheet last night and it came out with 115amps. Does that mean I should only run an 80amp breaker to the sub panel to avoid overloading my service?

 

[dcg9381]

I ran through the NEC Standard Electrical Load Calc worksheet last night and it came out with 115amps. Does that mean I should only run an 80amp breaker to the sub panel to avoid overloading my service?

That's the right way to do it on paper. I find that the load calc sheets are very conservative (meaning approaching worst case). I prefer to use an EMPORIA power monitor at the main (~$100) - gives monthly peaks and IMHO it's better than a load calc, but I realize in some cases a load calc is part of the requirement.

I believe Tesla charge rate (amps) is easily adjusted in their app.

 

[Stuff]

I ran through the NEC Standard Electrical Load Calc worksheet last night and it came out with 115amps. Does that mean I should only run an 80amp breaker to the sub panel to avoid overloading my service?

If you do the optional calc you would likely get under 100 amps. Anyway, it means you have 85 amps to work with before overloading the main. You can still do 100 amps, or even 200 do a sub panel. So a 50 amp charger and even a second one at 30 amps will have no issues with your overall service.

 

[wyliesdiesels]

i highly doubt hes running 115a all at once.... pretty hard to do so..