Nate Baxley wrote:
HorneTD wrote in message ink.net...

Replies are in line.

Nate Baxley wrote:

I bought an old farmhouse last year and I'm finally getting around to
fixing up some of the out buildings. The two that I'm working on now
each have power that comes from the main breaker panel in the house.
Each building has it's own fuse box with wiring extending from that.
Now on to the problem.

In the main breaker panel there are two seperate 30 Amp breakers that
each have a very large wire coming out of them. They aren't connected
like a double pole and aren't next to each other like a double pole
breaker. The two wires run into a single cable along with another
large wire wired to the neutral bus. The label on the cable is
"E32071 (UL) 3 CDRS AWG 6 TYPE SE CABLE STYLE U TYPE XHHW CDRS 600V".
Now, the cable goes out of the house and through the air to the first
building (Building A). Outside Building A there are severla wired
wired and taped together. One of the hot wires runs into bulding A
and the other wire splits into building A and also heads off to the
other building (Building B). Inside building A there is a fuse box
and the hot and neutral wires run to the normal connections. The
other hot wire and the split from the netural run through the air to
building B where the neutral and other hot wire run into a fuse box
and throughout the building.


Step one is to normalize the arrangement of the supply. Best practice
would be for the two thirty ampere breakers to be replaced with a double
pole breaker. In some panels the two breakers could be a double unit
and yet appear to be separate. Rearranging breakers in a panel must be
carefully done in order to avoid causing problems elsewhere while trying
to solve the problem on which you are focused.


Now for the question. I would like to replace the wires in the air
from A to B and replace the fuse boxes with a circuit panel. What I'm
considering is running both hots and the neutral into a 6 circuit
panel inside Building A and then running 1 circuit in A and 3 circuits
over to B through some underground conduit. The other issue that I
see is that currently at the splice outside building A the heavy wire
is spliced to some smaller old wire, it looks like around 10 gauge,
that runs from the outside into the building. I'm guessing that if I
splice the heavy wire coming from the house to a line into Building A
I need to keep it the same guage, right?


I'm going to guess that the installation will be done in an area were
the US National Electric Code is the standard for installations. You
cannot run multiple branch circuits from one building to another. Each
building must be supplied by a single branch circuit or feeder unless
the second circuit has totally different voltage characteristics or it
is an emergency circuit etc.

I'm guessing that you plan to run the new circuit underground. One way
to do this would be to place a splice box at the end of the first
underground raceway. You then run the feeder inside to the building
disconnecting means from the splices. The other leg of the feeder would
be run to the next building's disconnecting means and it would supply a
second feeder supplied breaker panel.

The other possibility would be to route the feeder to the building that
needs the three circuits. You could then run the single circuit to the
other building.
--
Tom H


Thanks Tom,
OK, I want to make sure I understand what you're telling me. My
explanation of running the main feed from the house to Building A
isn't a problem, it's the part about running the 3 circuits from A to
B, right? The problem is that A is physically between the house and
B. So I'd have to run under or through A to a circuit breaker in B
and then run a single circuit back, probably through the same conduit,
to A. Would that work? Does that make sense?


On your other comment about grounding, are you saying that I need to
have a ground wire that runs back to the main circuit breaker in the
house? What about installing a grounding rod a the new circuit
breaker? Would that aleviate the "stray currents" problem?

Thanks for your very informative post. I look forward to your reply.
Nate

Sorry for the long explanation, but I wanted to try and explain the
situation better. If a picture would help, I can sketch one quick and
post it to my website. Any thoughts that you have would be great.

Thanks,
Nate Baxley

You can run under A but not through it. You then run a single branch
circuit to building A. You might want to consider running a separate
branch circuit to building A from the main panel in the house and run
the feeder to building B. You can run those in the same conduit as long
as the feeder conductors do not enter building A. Having both circuits
run through the same pull box on the outside of building A is OK.

Read my reply to someone else on the grounding issue. Grounding will be
required at the building that has a panel in it. You run a four wire
feeder, terminate the neutral to an insulated neutral buss bar in the
panel, terminate the Equipment Grounding (bonding) Conductor (EGC) to
the bonded buss bar in the building B panel, install a grounding
electrode system at building B, connect the Grounding Electrode
Conductor (GEC) to the bonded buss bar in the building B panel.

If there are no metallic pathways between the two buildings you are not
required to run an EGC with the feeder. You are required to have a
grounding electrode system at each building that has more than a single
branch circuit run to it.

If you do not run an EGC with the feeder than you must bond the neutral
buss bar to the building B building disconnecting means enclosure, i.e.
to the building B panel cabinet.

The building B panel must be marked as suitable for use as service
equipment. If the building B panel will contain more than six breakers
either now or in the future you must provide a building disconnecting
means in the form of a main breaker or in a disconnect ahead of the
building B panel that is located on or in building B.

The stray current problem is caused by running a three wire feeder
rather than a four wire feeder with a separate EGC. Since you have to
bond the grounded current carrying conductor to ground at each building
if you do not run a separate EGC with the feeder the neutral currents
will be divided between the neutral conductor and the earth. This can
cause a step potential across the surface of the earth between the two
buildings to which some livestock are extremely sensitive.

Once again the best practice is a four wire feeder even though the code
allows a three wire feeder in the absence of other conductive pathways
between the buildings.

No matter which feeder you run you must build a grounding electrode
system at each building that is supplied by more than one branch circuit.
--
Tom H