20 amps is plenty if you have a short commute. I currently charge my S at 15 amps since the 50amp breaker is running off a spa subpanel. With my 70 mile round trip commute it charges fine with scheduled charging starting at 10pm. I leave for work just before 8am.
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Difficult situation with a Condo, advice appreciated...
- Thread starter MetricExpanse
- Start date
NikolaRocksOn
Member
Ours is long range X, we installed a NEMA 14-50 & that is plenty to charge her up to 80% over night. The electrician charged ~ $500 to run a very tidy overhead conduit from the 50amp breaker (25 ft.), to the 14-50. Otherwise the supercharger is ~ 15 miles north & another one ~ 25 miles south. I didn’t read all the ”replies” apologies for any duplication or irrelevance.
Just gotta say... that $1000 for a manlift is nuts! Haven't they heard of an extension ladder? Even if they need a lift, it seems like a ton of dough.
Keep in mind, I don't know which floor your condo is on, and I'd be hard-pressed to reach above 30 feet with my own ladder. I've been on a ~40 foot ladder before and was quite disturbed by it. I'd probably put the first segment of conduit up by hanging out a window and that would get me down 10'.
Keep in mind, I don't know which floor your condo is on, and I'd be hard-pressed to reach above 30 feet with my own ladder. I've been on a ~40 foot ladder before and was quite disturbed by it. I'd probably put the first segment of conduit up by hanging out a window and that would get me down 10'.
Your panel is not the issue - it is rated for 125 amps. What’s important is the size of the conductors feeding the panel and the amount of load currently on the panel. You or an electrician can check the conductor size and measure the amps delivered when most everything in your place is on; AC, range, dryer, lights, etc. 2 AWG copper wire can handle 100 amps, 4 AWG 70 amps. If you have additional capacity, I would find an electrician willing to run directly from your panel to your parking spot, the 80’ you mention.
Just because the washer and drier each have a 20A circuit doesn't mean they draw more energy. The drier is gas, so it isn't going to cause any issues.
Yes, I totally agree.
What I was originally getting at was that retiring two circuits of breaker size N does not allow OP to install an N(or an N times two! as was originally suggested by a third party) sized 240 volt breaker that he KNOWS will be full-on for hours at a time.
400 feet is considered a long run, so the conductor should be sized up some to reduce the voltage drop going that distance, so it should be heavier than 4awg. If it's just 4AWG, oh boy! 5% drop in voltage at 70A over 400 feet would require 3AWG. Limiting it to only 3% would require 1/0AWG.
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Really good analysis! I think it shows that I do have a lot of headroom with a 70A breaker for doing 30A charging. I will definitely call my electric company to see if they have my peak usage info.
Also, an interesting thing that just happened just now. I had the first electrician (the one who wanted to run from my meter) over to redo his estimate. He looked at my breaker panel and found my main feeder wire to be 4 AWG Copper THHN and so he wants to replace my main breaker with a 100A breaker. Then he wants to put a 50 or 60A branch circuit for the EV charging.
Assuming this is all safe and OK to do, that would solve my 70A limitation problem and get pretty good 50-60A charging, right? I worry a bit if the HOA isn't going to like me upgrading my service like that, however.
Also, just for fun, some pictures from the electrician's visit after he cracked open my load center. Couldn't get super close due to social distancing, but kind of interesting I guess. 
If the run is REALLY 400 feet, this is a terrible idea. 3AWG THHN jacket in conduit is rated for 100 while connected to an actual breaker. (Breakers have a limit of 75C)
85A is the absolute highest you can go on 4AWG and that assumes reasonable distance and nothing baking in the sun. See my post above about distance and voltage drops and NEC code around that.
Also looking at your panel, I think the bonding screw is installed, which it shouldn't be in your configuration. You wouldn't believe how often this happens. It can cause issues if a neutral comes loose someplace and the earth ground ends up carrying the load. This isn't good because earth ground wires are bare and connected to things humans touch.Also, just for fun, some pictures from the electrician's visit after he cracked open my load center. Couldn't get super close due to social distancing, but kind of interesting I guess.
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I wouldn't run that gauge wire 400 feet with a 70A load. Per the NEC you should have 1/0 to keep under 3% voltage drop. The city approved it when it was built so it "must be fine". Even if your detailed usage shows you can do 30A, I would stick with a 20A circuit (16A to the car) to keep from melting that 4AWG wire.
When you say 400 feet, is that the total amount of wire required to do the job, or the distance of conduit? I have been assuming you have 400 feet of conduit, and things would be different if you only have 100 feet of conduit.
I figured it was sounding “too good to be true”... I mean they must have originally put a 70A breaker for a reason, right? I have another electrician coming next Thursday and I will get his second opinion. Perhaps he will be more conservative.
I wondered where this guy was getting the 100A figure from, though. I found this: https://www.usawire-cable.com/pdf/nec-ampacities.pdf. It seems to have the same info you posted, but there is a weird little carve-out table at the bottom suggesting that 100A might be okay in certain situations? I wonder if this is what my guy had in mind when he told me what he did? Regardless, I don't want to do anything unsafe and so I think I'll see what the other electrician says before I charge into it.
Correct, there are exceptions and allowances, but I wouldn't go there. The assumption is that these are typically very short runs, maximum of a few feet per other parts of the code.
You should ask every electrician if they intend to pull a permit. If you find any that plan to, I will be surprised. They can do anything they want if the city doesn't inspect it, and all the liability then falls on you for their decisions. If you have a fire, and the insurance company finds an unapproved change caused it, then they can deny your claim.
I am not an electrician, but I vaguely recall that the NEC allows rounding UP to the next larger breaker size(rather inexplicably, I must admit), if the ampacity of the circuit lands between two generally available breaker sizes. Unless there's something about 100 amp breakers having 90C rated lugs, it sounds like the 95 rounding up to 100 wouldn't apply here anyway.
Hmm, good point. You know, when I have the other guy come over, I'll ask him about that and get it dealt with if it's not okay.
Yeah, so you're thinking even my main feeder has already got too high of a service level for my feeder wire? The 400 feet figure was the run distance from the meter to where my car is parked.
I don't know how long this 4 AWG wire is, but my apartment is near my car, so I guess it's also somewhere around 400 ft run inside the walls of my building. I do wonder if I've misidentified where my meter is... it's a possibility since I haven't actually *looked* at my own meter.
All the electricians I'm working with intend to pull a permit for the work, including the company that wants to upgrade my main breaker to 100A. So I assume this guy thinks it'll pass LA city inspection...
davewill
Active Member
In a multi-family dwelling like this, it would be absolute madness NOT to have the work properly permitted and inspected. Insurance would be the least of your worries...criminal negligence would be a real concern.
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