On 10/5/11 10:16 AM, Eisboch wrote:


"X ` Man" wrote in message
m...

On 10/5/11 9:53 AM, Eisboch wrote:


"X ` Man" wrote in message ...



I'll do light electrical work, such as replacing a wall switch or
ceiling fixture, but that's about it. The labor for the new generator
involves electricians and a plumber, and the charges for both services
are estimated at around $2500. The job has to be permitted, at least as
far as the plumbing goes. The genny is an LP gas appliance. I don't mess
with installing gas appliances or heavier duty electric, especially when
the wiring or pipes are to be concealed.

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The following is typical of a house service backup generator:

If your generator supplies 220/240 volts across the hot leads and
115/120 volts between either of the "hot" leads to neutral,
the neutral, current carrying conductor does not have to be the same
size as the hot leads.
It will only carry *half* of the the max generator current at full load.
"Why?" you ask?

Because the two hot leads (L1 and L2) are 180 degrees out of phase with
each other. The current flowing through
either L1 or L2 add algebraically in the neutral line. A 240 v powered
device in your house draws *no* current
through the neutral line. If you have two 120 volt appliances, one
operating from L1 to neutral and the other L2 to
neutral and both draw 10 amperes, the current in the neutral line is
zero. Cool, huh?

Eisboch


Hehehe...I'll reread your post a few times...right now, all I hear is a
"whoosh" sound.

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Just to clarify ... I am talking about the wiring that will run from
your genset to the transfer
switch connected to your house power panel. ... You should *definitely*
have an automatic
transfer switch. Worse thing you want is to have commercial power come
back on while
you are running on the generator power and the two are not isolated from
each other.
Bad things can happen.

I like to ask electricians the question about the neutral wire size.
Many don't know why .... they just go by the code book.

Eisboch

Yes, we'll have an auto transfer switch.

Specifically, the new genset will be located at the back of the house,
close to where the metal pipe line from the buried LP gas tank comes out
of the ground and enters the house. The alternative was to place the
genny on the side of the house, adjacent to where the utility power
enters the house and finds the breaker boxes on the other side of the
concrete foundation wall. But that would have required nearly 100' of
buried gas line, and doing that would have been far more expensive than
running a heavy electric wire in the space between the first and ground
levels. That run is between 50' and 60' and is reasonably accessible.

So, if you were specifying the wiring from the genny to the breaker box,
assuming an output at the genny of 70 to 100 amps, what would you choose?

Thanks.

--
I'll believe corporations are people when Texas executes one.