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New to charging at home and work, 110v and 220v
- Thread starter tubaprde
- Start date
dhanson865
Well-Known Member
220 is dangerously low on a 240v circuit and just slightly high on a 208v circuit (not dangerously high, just higher than normal by about 6%).
So it still falls back to is this a 208v or 240v feed?
If 208v off 3 phase, then replace outlet and all is good.
If 240v that is sagging down to 220v or less under load, then the outlet, wire run, breaker are all suspect and need to be checked out before using even one more charging session.
ucmndd
Well-Known Member
The fact that you’re seeing 220v on the multimeter with no load but 210v when the car is charging is kind of concerning.
210 would be a perfectly normal reading for a 208 circuit from a 3 phase power source, but 220v is quite high for 208 and way low for 240.
210 would be a perfectly normal reading for a 208 circuit from a 3 phase power source, but 220v is quite high for 208 and way low for 240.
It's disturbing that this is so far off that it's hard to tell whether your building has 208V or 240V service. Here's the thing though:
If you have good solid service from the electric company, it may be a few volts high. But anything within your house, through the wiring runs, connections, etc. can only make it go lower with extra losses, not higher. So I can't possibly see any way that this is a 208V nominal and is somehow getting boosted to 220V. It is almost certain that this is supposed to be 240V, and already has some nasty voltage drop from weak wiring to 220V with no load, and then is getting dragged down even further to 210V when it gets some significant load on it. This sounds like it's already a pretty bad wiring situation.
It's funny--the car has a safety measure that will try to detect for a significant voltage drop from the no load to the loaded charging condition. But I wonder if because it's so low to start with, and low amps, that the extra drop isn't enough to trigger that.
If you have good solid service from the electric company, it may be a few volts high. But anything within your house, through the wiring runs, connections, etc. can only make it go lower with extra losses, not higher. So I can't possibly see any way that this is a 208V nominal and is somehow getting boosted to 220V. It is almost certain that this is supposed to be 240V, and already has some nasty voltage drop from weak wiring to 220V with no load, and then is getting dragged down even further to 210V when it gets some significant load on it. This sounds like it's already a pretty bad wiring situation.
It's funny--the car has a safety measure that will try to detect for a significant voltage drop from the no load to the loaded charging condition. But I wonder if because it's so low to start with, and low amps, that the extra drop isn't enough to trigger that.
M3BlueGeorgia
Active Member
Or be safe with 6-15
I'd prefer 10 gauge for 6-20 and 8 gauge for 14-30 and 6 gauge for 14-50.
It could definitely mean...absolutely anything or nothing. The position of the outlet has no bearing on it at all and doesn't indicate anything about what voltage the building uses.
davewill
Active Member
My first thought on seeing it is that someone might have upgraded the garage door circuit to that box from 120v to 208/240v and failed to notice that little 5-15 branched off of it. I would want to see the inside of that box before I relied on that circuit for anything.
Agreed! Very possible. Please do not use this circuit. Charge your car from a known, dedicated circuit, either 120 or 240 volt. Have an electrician sort this out for you. The fact that it floats from 220 to 210 under load could mean other service issues (disconnected or bad service neutral) or possibly-- but unlikely--accidentally wired to the stinger leg of a 240 delta service.
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ucmndd
Well-Known Member
This seems like the most likely scenario to me given the additional pictures. Didn't realize we were talking about a commercial garage door and it's obviously been replaced with new equipment sometime in the recent past.
ucmndd
Well-Known Member
OP, I also just realized that you mentioned you're using an extension cord. If it's the one in that picture, which I assume it is, that could certainly explain a 10v drop under load.
ThanksOr be safe with 6-15
I'd prefer 10 gauge for 6-20 and 8 gauge for 14-30 and 6 gauge for 14-50.
yeah all good points here. ... OK, a shorter cord is better. I’ll def still get 10AWG of the appropriate length and then make sure it’s laid out straight (not bundled/bunched up) so it can keep cool.
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