I am far from an electrician and would only ever hire a licensed electricia
n to do any major electrical work on my home. But I am reasonably comforta
ble measuring AC voltages.
In 2013 we had a 240V electric car charging station installed in our garage
. 50 amp breaker, 6 gauge wire. The actual unit is convenient, because it
has a plug and is designed to plug in to a 240V outlet. For reference, it
is Leviton EVB40-SPT Level 2 surface mount charging station. So we had our
electrician install and wire a 240V receptacle on a dedicated 50A circuit,
mounted the unit on the wall above the receptacle and plugged it in. All
appeared to work just fine for about two years.
Then, a couple of years in, it started having this issue where the unit wou
ld rapidly click (on/of) when charging (though it did always charge the car
- Nissan Leaf). When trying to troubleshoot this, I noticed that turning
the garage light on (different circuit) or turning on another light in the
adjacent room on (other different circuit) would cause the clicking to stop
. It's hard to say how long this problem existed prior to discovery, since
normally the car would charge at night when we were asleep (taking advanta
ge of our dual rate electric). But since we would occasionally plug it in
during the day for a recharge, we eventually noticed this issue.
Recently (since we are between electric cars) I have sent the unit back to
the company to be tested.
For further troubleshooting, I recently measured the voltage at the recepta
cle. The first time I did this, I measured the voltage at around 238V (ove
r the course of a few minutes I measured the voltage at values between 238V
and 238.8V) - with garage lights on. I measured the next day and the volt
age was closer to 242V (slowly fluctuating between 241V and 242V). Both ti
mes, during the few minutes I was measuring, the voltage would slowly fluct
uate within about half a volt of the avg. value. I also measured the volta
ge between the neutral and hot terminals and found that those values were e
ach about half of the total (as expected), but importantly, that they were
the same value - though when I was measuring the first time around, I thoug
ht that one side was consistently about 0.2V higher than the other side. I
didn't see that 0.2V variation the second time I measured. On my second t
est, I remembered to turn the lights on and off to check for differences.
I found no discernible difference in voltage with the lights on or off.
I know that household voltage fluctuates, but I can't seem to find a defini
tive answer about how much fluctuation is normal or acceptable. Furthermor
e, when talking to the tech on the phone earlier, he made the claim that th
e voltage had to be *above*
240. That just sounded completely wrong to me.
I was pretty sure that any appliance was supposed to work between a range
of voltages. If anything, I might be worried about voltages above 240, sin
ce 220-240V is often a range I hear.
Can someone on here with electrical wiring knowledge let me know if it soun
ds like the voltage I measured at this outlet is within the normal range fo
r household service, and if the fluctuation that I measured seems normal?