Big Al wrote:

"TKM" wrote in message
...

"RBM" wrote in message
...

"scrapwood" wrote in message
...
I have a question that I can't seem to find an answer to.

The task is adding a new sub-panel in an outbuilding. I understand that
new sub-panels now require a 4-wire feeder line, however this feeder
will
be coming from the service disconnect. Specifically, it will be coming
from a small lug box on the side of the service disconnect; because this
is how the existing outbuildings are being fed.

So, my quesiton is: Is the fourth wire required in this situation,
coming
off the disconnect. If it is required, what is it connected to??

Thanks in advance for any advice!
scrapwood.

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I'm not completely sure I understand your situation, however, if this
feeder to the outbuilding is connected to the "load" side of the service
disconnect, it will require four wires for a 120/240 volt feeder. Two hot
legs, one neutral, and one ground. You may have to drive additional
ground rods at the outbuilding as well

The ground line can be bare and is sometimes wrapped around the others to
make a sturdy cable.

But there's another possibility if you have heavy motor loads. What you
heard could apply to a 3-phase system and, specifically, a 3-phase "Y"
system which has 4 wires.

TKM


So, what would a delta have? My house has 240V 3 Phase Delta service, four
wires come from the pole to the house. Three are standard single phase, two
hot, one common. The other is the so called "wild" leg. No ground. Ground is
bonded to the water line and tied to a ground rod just under the meter.

Al

You'd still have 5 wires feeding a sub panel, your three hots (including
the "wild" one), your neutral a.k.a. your common, and the ground which
is bonded to your neutral at your service entrance. The key thing here
is we're talking about what is required to be feeding a sub panel, not
what is feeding from the utility to your service disconnecting means.