On Dec 19, 9:41*am, spamtrap1888 wrote:
On Dec 19, 6:08*am, klem kedidelhopper
wrote:



On Dec 18, 11:18*pm, Jeff Liebermann wrote:

On Sat, 17 Dec 2011 10:59:52 -0800 (PST), klem kedidelhopper

wrote:
Our area suffers from frequent blackouts, and many people including
myself use generators, (manually) during these periods. It would be
really helpful to know when the utility side of the circuit is once
again live so that I can put the generator away. Basically I need to
monitor the entrance cable side ahead of the main.

The neon lamp method works. *You'll need one for each phase.

However, I smell a different problem. *I couldn't see why you would
need to monitor the voltage before the main breaker. *If you had a
proper transfer switch, it wouldn't be necessary:
http://www2.northerntool.com/generators/transfer-switches-4.htm
If you're powering some appliances with an extension cord, you can
tell if the power has returned when the house lights come back on.

My guess(tm) is that you're opening the main breaker when the power
dies, and back feeding a wall outlet with a suicide cord (a power plug
on each end of the cable). *If you're really clever, you'll backfeed
both phases with a 220VAC suicide cord.

The 220VAC version will work, but the single phase suicide cord has a
problem. *Under normal conditions, the current through the neutral
wire is nearly zero. *That's because the 180 degree phase difference
between each phase cancels the current in the neutral wire. *However,
with only one phase powered, you're likely to see the full current
through the neutral. *If you're creative and parallel both phases,
then the neutral current is even higher. *Code compliant wiring can
survive this, but I've seen a few blown neutrals. *That's when the
neutral wiring was rotten, and nobody noticed until the full current
was applied.

Another problem is that when you back feed a single wall outlet with a
suicide cord, you're going to be limited by the current limit of the
connected circuit breaker. *In the US, that's about 15A. *That should
be sufficient for most loads, but I suggest to disconnect the high
current loads to prevent blowing the breaker.
I think that what you may be talking about Jeff is an "automatic"
transfer operation. This sounds like a system that will automatically
start the generator on sensing a loss of power, and then activate a
huge double pole contactor. Then when power is restored the generator
is stopped, and the contactor switches state. This is a whole house
system and you're correct in that you would not need to monitor the
utility because the generator system would do it for you. However if
you look at the first example of a transfer switch on the page you
included with your post you'll notice that the example is a manual
switch which controls six circuits. To utilize this switch you pull
six loads out of your panel and wire them through this switch. The
generator is manually operated and essentially the utility mains is on
one side of a double pole switch, (if you will), the generator is on
the other side, and the load, (house) is in the center. In any case
and regardless of what system you use, there can't be any connection
between your generator and the transformer on the pole. Therefore, and
please correct me if I'm wrong but *it would seem that with any manual
system, whether you use one of these manual switches or you back feed
a 240 volt circuit and manually kill the main, you would have no way
of knowing when the utility is back in service. Lenny

I suggest that Klem adopt this philosophy of life, instead of being
Nick Negative:

"As you go through life, make this your goal: Keep your eye on the
doughnut and not on the hole."

The manual transfer switches connect only certain house circuits to a
portable generator -- presumably those powering appliances that the
homeowner deems to be critical. The rest of the household circuits
will be unenergized until the mains power is back on. So the owner
will know to shut the generator off when all the lights and radios,
etc. come on.

Thank you for correcting me on that point. But in what way was I being
negative? Doughnuts are no good for you. Lenny