Installing a car charger in my garage

Hello,

I just received a car charger in the mail today for my plug in hybrid car. The charger I bought is made by Clipper Creek and requires a 20A 220V circuit. I plan on having an electrician hook this up at some point, but I have 2 questions...

1) This is supposed to be hard-wired into a 20A circuit. It will be on a circuit all by itself. Someday I might get a new car that can charge at a faster rate and want a charger that runs on a 30-50A circuit. If I use 6/2 wire and a 40A breaker would this be dangerous since the device only draws 20A? If so, could I still run the 6/2 wire but use a 20A breaker?

2) Is there a way to temporarily connect this device to a 20A 110V circuit and have it just work at a slower rate than it is supposed to? I would assume not since the 110V circuits only have 1 hot wire. What if I hooked it up to some 12/3 wiring where there were 2 hot wires? I'm assuming this is all a terrible idea, but I thought I'd ask.

 

As to #1, it's perfectly ok to have a lower draw device on a higher rated circuit as long as you don't have to modify any plugs or cords.

For #2...unless the manufacturer offers that option, no.

 

How is the garage wired now?
What size wire was used.
Attached to the home?

 

But will actually use 240 volts, nominal residential voltage.6-2 would be cable not wire*. Yes but where is the receptacle going. That will determine the type of cable. #6 won't fit a 20 amp receptacle and may not fit a 20 amp breaker so you will have to pigtail to a smaller wire that will fit. If this is a detached garage though you are going to need a subpanel. Even if attaches a subpanel may be the better solution. Give us more details and we can better help.

*Terminology: Cable is two or more wires in a metallic or non metallic sheath,

 

The best way to plan for future expansion is to have your electrician install the circuit using individual conductors in 3/4" conduit instead of a cable. When you buy a new charger, the wires in the conduit can be replaced with the appropriate size wires for the new charger. For now, you'd just be making a guess as to what the future technology will require, and you'll probably guess wrong.

According to the instruction manual of your current charge LCS-20, there is no provision for temporary connection. It must be hardwired to a permanent 20A 240V circuit. That circuit must have wires at least #12, and a breaker or fuse no larger than 20A.

 

A little more info...

My garage is attached. I believe I have a 100A main breaker. I just had solar panels installed and they created a subpanel which was powered by a 50A breaker. I have no idea how to tell whether or not I can add more to that subpanel before it overloads. I don't think there is any space left in the main panel.

My garage is currently wired with 12/2 on a 20A circuit.

As for the conduit idea...

What is the approximate difference in cost for an install if I use 6/2 cable without a conduit vs. 12/2 romex in a 3/4 inch conduit? From my panel to the install location on the other side of the garage is about 30 feet.

 

Post a picture of your main panel with the cover off. http://www.doityourself.com/forum/li...rt-images.html

 

The cost depends entirely on the route the cable or conduit needs to follow and how easy or hard it is to install. If it's a straight shot, the labor shouldn't be much different.

 

Here you go...

Main panel:


Sub panel:

 

Odd that your installer / electrician put in a 50A panel, and then put a 50A air conditioner in it. The AC breaker is probably oversized a bit to account for motor start-up, but your subpanel is pretty close to full. Plus it appears you have all electric appliances and a pool? Just gut feeling without doing the calculation, but your 100A service is probably too small or at least right on the cusp. Do you know if a demand load calculation was done as part of this recent work? If so did they figure in the car charger?

The current charger is iffy (a load calc should be done), but a larger one is out of the question without a 200A service upgrade.

 

I was wondering why he put the 50A AC in the 50A panel, but what do I know?

My appliances are actually not electric. I have a gas stove, gas hot water heater, and gas dryer. I think there are 220 outlets where the dryer and stove are so that I have the option of electric. I do have an inground pool though, so you are correct there.

I don't think a load calculation was done, or if it was I don't have it.

Upgrading to a 200A breaker would be rather expensive I'm assuming?

 

http://www.nojolt.com/load_calculations.shtml

 

I got 96 amps using that, but I have no idea if I was accurate with some of the numbers I gave.

My house is 1496 square feet. I have 1 refrigerator, an above-the-oven microwave, central AC, and a pool which are the large drawers of electricity. Other than that, it's just computers, lights, and outlets.

 

Looking at my panel some more, it looks like I have a 30A breaker for a dryer and a 40A breaker for a range. Given that my appliances are both gas, could I (the electrician I'd hire) disconnect those wires from the breaker and just leave the wiring intact in case I ever someday upgrade to a 125-200A panel?

Also, I just pulled out my stove and the receptacle says 50A on it, but the breaker is only 40A. Is this important?

 

Yes.Only if you plan to use it but it might not be even then.

 

One thing to note is Romex can not be run on the surface of a wall, it needs to be protected where it can be damaged. Conduit is a better option.

 

That's good news then. I'd say the odds of me ever having an electric oven or dryer are about 0%

I think I like the conduit idea for running the cables in my wall and use 12 gauge wire for now since it will be at least 5 years before I might need to upgrade the car charger. That leads to several more questions...

1) Do I have to run THHN cables through the conduit rather than romex?
2) Can conduit go inside the wall once I finish the garage?
3) Am I likely to save much money by running all the conduit and cables myself and just leave the connecting to the breaker box part up to an electrician? I've done plenty of wiring before (mainly adding outlets and lighting to pre-existing circuits) so this isn't really much different...just use a red wire instead of a white wire.

 

No matter what happens, this is going to be hidden inside of the wall. My garage is partially-finished (walls only) but the drywall that is in place is in pretty bad shape and I want to rip it all out and start over. My garage only has 3 outlets and 1 overhead light (just a bulb) so it needs some remodeling down the line.

My garage doesn't currently have much power going to it, but I don't plan on using it as a garage. I want to get a pool table and bar setup in there...none of that requires much power.

It might also be worth mentioning that I plan on putting the car charger on the outside of the garage rather than inside. I think I neglected to mention that earlier, but it shouldn't make much of a difference.

 

As long as the charger is designed to be outside that should be OK. Just make sure the install for the electrical is weather proof.

Bar to me equals pizza oven, blender, microwave, toaster oven. All high draw items. You may want to consider installing a sub panel in the garage, then from there you have the flexibility to add whatever you need.

 

I got the indoor/outdoor one so I'm good there. I plan on doing a weatherproof install and using indoor/outdoor wiring.

I think I meant more like maybe a mini fridge, sink, and then a bar counter to store liquor or whatever. I'd also like to get a pool table (no electricity) and maybe a pinball machine or something (not too much electricity...I don't think).

I would like a subpanel as well, but won't that require upgrading my main panel? If I'm borderline maxed out on my 100A panel, will adding a subpanel in the garage really help if the main panel remains 100A?

 

No, it doesn't work like that. You could keep adding sub panel until the cows come home and be just fine. It is all about the load that is on your service. A sub panel is just available load. IMO you are boarder line on your service because you said your oven and dryer are gas.

 

Would this Southwire THHN 12 gauge wire work in a conduit that leads to an outdoor receptacle? Most of the romex will say indoor or indoor/outdoor, but this THHN wire at Home Depot doesn't seem to say one way or the other.

For what it's worth, the receptacle to my car charger won't have a plug, it'll just be a capped off junction box (that is rated for outdoor/wet locations)

 

That is because the copywriters and even the store associates usually misidentify it. It is actually dual rated THHN/THWN. Just check the writing on it before buying.

 

Okay, so that's the wire I will use.

Is there any reason I shouldn't wire this just shy of the panel myself (and let the electrician hook it up since I don't know how/ am afraid to try)? Like I said, I've run romex a bunch of times and know how to add lights, switches, outlets, etc. All I'm doing is running conduit through the walls and then running 12 gauge red/black/green wire through it (no common wire needed for my device). At the one end I'll connect the wires to the charger and the other end I'll leave a bunch of slack so the professional can connect it like it's supposed to be connected. Actually, can the green wire be 14 gauge on a 20A circuit? I thought I've heard that.

Also, is there a disadvantage (other than cost) to using the flexible conduits? I'm kind of lazy and would rather skip PVC and this stuff seems easy-to-use.

 

Many electricians will refuse because he is in effect accepting liability for your work, it will be his name on the permit and his license at risk if anything goes wrong.

With the main breaker off working in the panel is relatively safe. Only the area around the main breaker will still be hot. You will basically pull on of the 240 breakers previously mentioned and replace it with a 20 amp breaker.

There is a way to do this without working in the breaker box but it will cost more and be just a bit more complicated. You would re-purpose the electric stove 40 amp circuit for a subpanel in the garage. Cost wise it might be about the same as or less than getting an electrician, if you can find one, to make the final connection.

 

What if I run the conduit but don't fish the wires through it? It seems like running conduit, knocking holes in drywall, etc. is rather labor intensive and I'd rather not pay someone to do it since I can quite easily do it myself. I used to have a good friend that is a master electrician that helped me with a bunch of stuff, but unfortunately he no longer lives close enough to help me with this. He showed me how to do a bunch of stuff, but working with the breaker box is not one of them.

This makes me think this might be something I should do myself even though everywhere I read online says not to even think about doing this yourself (then again, I've read that you shouldn't even try to change an outlet without calling an electrician ).

If I disconnect the 30A breaker, what do I do with the wires leading into the 30A breaker? I also don't have a clue how to install a 20A breaker, where each wire goes, etc. I've seen youtube videos and could probably figure it out, but it makes me nervous. I'm also not sure how to get the wires into the breaker box. I see where a ton of wires come out of my garage wall so I'd guess I just shoot them down there and hope for the best?

Are you saying buy a subpanel, mount it, install wires leading up to it, and then the electrician can wire from the subpanel to the main breaker? Wouldn't they still be accepting liability for my work? I'd be more than happy to attempt this, but I'm not sure this is what you meant.

 

No. I'm saying run the wires yourself from the stove receptacle to a subpanel in the garage. In that subpanel you would put the 20 amp breaker for the charger. Basically you remove the stove receptacle and wire nut the wires from the main panel to the wires to the new subpanel and then put a blank cover plate on the stove receptacle box.

To be able to do this there must be a ground wire at the stove receptacle. If it is a 4 prong receptacle it likely has a ground. You will also need to determine the size cable (or wire if in conduit) from the main breaker box to the stove receptacle. You should be able find it printed on the cable jacket.

 

Hmm...that actually sounds like something I could do. It might be difficult to figure out how to get the wires from the stove to the attic, but I could probably figure it out. Worst-case scenario I destroy a bunch of drywall behind the stove and do a bad patching job, but who cares, you'll never see it? The stove outlet does in fact have 4 prongs.

Assuming I do this and stick with the 40A breaker on my main box, what exactly could I put in the subpanel? Obviously I could never get a 50A circuit for the car charger, but that's probably not a huge deal.

If I someday upgraded to a 30A circuit for the car charger, how many 20A circuits would I be able to (realistically) add for lighting/outlets in the garage? If I instead elected for a 40A circuit for the car charger how many (if any) 20A circuits would be acceptable for the garage.

On a related note, is it worth bothering using a 20A circuit for outlets/lighting or is 15A sufficient? I know my house has almost exclusively 20A breakers but there are a few that are 15A and I don't think they've ever tripped.

 

I'd probably leave the range receptacle as-is and install new circuits for your garage / charger fed from the existing subpanel. You'll want to sell this house someday and maybe the new owners prefer an electric stove. That subpanel could easily be upgraded to 100A if you really need to someday -- it's a mystery to me why they didn't do that to start with, but oh well that's what you have to work with.

I see no problem with you running the conduit, mounting the box(es) and doing other assorted grunt work prior to the electrician's arrival. As long as you make sure to follow code per number of bends, proper fittings, support and straps. You could buy a pipe bender or just use all prefab fittings.

The code doesn't really specify how many 20A circuits you can run -- it's all based on actual or anticipated loads. If you're making a complete guess, the code uses a figure of 3 watts per square foot of general living space. You can use 15A circuits if you want for general living areas (not kitchen, bath or laundry), but I generally recommend 20A. You get 33% more power available for the same labor.