DIY Electric Car Forums banner

1 - 1 of 1 Posts

70 Posts
Discussion Starter #1
I have seen this happen many times, it's a common fault:

The Neutral coming in from the transformer corrodes, oxidizes, or fails in
some way. It's usually in the main service panel. Sometimes, it's not
completely open, just high resistance. This can be compounded by an
imbalanced loading.

If the neutral isn't a good low-resistance path, what will happen is you
will switch on too many loads on one hot leg, and it will cause the voltage
to drop. The majority of the current is returning though the other hot leg
through your loads instead of neutral. That causes the other leg to go too

If you have easy access to a 240v outlet, and a voltmeter, you can test for
this. I don't advise removing the cover from the service panel to perform
this test unless you are experienced with electrical wiring.

Connect one lead of the meter to neutral, and then alternately connect the
remaining lead to each of the hots in turn. If they differ by more than 5%
you likely have a problem!

If you are competent and have experience working in live service panels, you
can remove the cover and perform this test there. If you see any evidence
of heat or discoloration around the neutral terminals, then you have
probably found your problem. If not, repeat the meter test here, and if
it's still off, call your power company. They are responsible!

Save all receipts for bulbs, appliances, etc. They will credit you.

----- Original Message -----
From: "Aliza" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Monday, October 29, 2007 1:32 PM
Subject: Re: [EVDL] Electrical Standards

>I sure hope someone talks about the OT light bulb thing. I am about to go
> crazy going through bulbs in my old farm house. Perhaps if someone has
> some
> help they could contact me off list.
> Aliza
> ----- Original Message -----
> From: <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Monday, October 29, 2007 12:59 PM
> Subject: Re: [EVDL] Electrical Standards
>> [This might be off topic... or it might help people understand
>> electricity better]
>> (-Phil-) wrote:
>>> Funny this discussion of standards, when most people still call US
>>> standard
>>> voltage 110v when it's been 120v for over a half of a century.
>> ...
>>> Here in the US, we can generally only expect 1.8kw, (or 1.65kw for all
>>> you
>>> 110'ers) although most newer circuits deliver more, even if that's all
>>> the
>>> outlet is technically rated for.
>> I was getting 157v out of a 20-amp, 125v circuit the other day. If
>> there is a nominal range (and I have seen 110-120 out of a 15-amp, 120v
>> circuit and consider that 'nominal'), is 157v in it or out of it for
>> this circuit?
>> I'm wondering if voltage surges and fluctuations could be responsible
>> for the remarkably high failure rate of light bulbs in my house (even
>> well-rated Sylvania CFLs, which I've been slowly converting to).
>> To try and yank this back to EVs: does voltage variability in the home
>> impact how the charger handles charging?
>> _______________________________________________
>> For subscription options, see
> _______________________________________________
> For subscription options, see

For subscription options, see
1 - 1 of 1 Posts