This may be a little OT, but I sure could use some help. I've built a 12x24
multi-use shed, mainly intended to store my hardwood boards and increase
accessibility to those that always seem to be on the bottom. The wood racks
look great. In any case, I'm wiring it for lights, receptacles, exterior
lights and to feed power to a garden pump.

I have a Siemans breaker panel with a 100A main breaker installed. I would
like to have a main breaker handy in the shed. There are two vertical bus
bars which are presently connected by a removable insulated strap that
crosses the midline. One of these vertical bus bars has a green screw that,
if turned, will bond that bar (and the other one too if the strap is left in
place) to the metal case.

The connection to power, which once went to a panel in a mobile home now
replaced by the shed, arrives underground from the meter box (my meter is on
a pole remote from the house and I made the large temp panel there permanent
because the service is split there for several uses) in the form of *four*
insulated #4s: two hot wires, a neutral and a ground. These are controlled
by a 100A 220V breaker at the meter panel.

At the shed, am I supposed to isolate the neutral bus bar (by removing the
strap) and connect my neutrals all there and then ground the case with the
green screw and connect all my grounds to the now separate ground bus bar?
This would replicate the arriving connections and seems right to me, but
what do I know?

Any advice will certainly be appreciated.

Bill

On Thu, 07 Aug 2003 17:44:30 GMT, "William Hinshaw"
wrote:

This may be a little OT, but I sure could use some help. I've built a 12x24
multi-use shed, mainly intended to store my hardwood boards and increase
accessibility to those that always seem to be on the bottom. The wood racks
look great. In any case, I'm wiring it for lights, receptacles, exterior
lights and to feed power to a garden pump.

I have a Siemans breaker panel with a 100A main breaker installed. I would
like to have a main breaker handy in the shed. There are two vertical bus
bars which are presently connected by a removable insulated strap that
crosses the midline. One of these vertical bus bars has a green screw that,
if turned, will bond that bar (and the other one too if the strap is left in
place) to the metal case.

The connection to power, which once went to a panel in a mobile home now
replaced by the shed, arrives underground from the meter box (my meter is on
a pole remote from the house and I made the large temp panel there permanent
because the service is split there for several uses) in the form of *four*
insulated #4s: two hot wires, a neutral and a ground. These are controlled
by a 100A 220V breaker at the meter panel.

At the shed, am I supposed to isolate the neutral bus bar (by removing the
strap) and connect my neutrals all there and then ground the case with the
green screw and connect all my grounds to the now separate ground bus bar?
This would replicate the arriving connections and seems right to me, but
what do I know?

Any advice will certainly be appreciated.

Bill

Someone here might have an answer. Personally, some of what you wrote
seems contradictory to me - at least confusing. If no answer here, you
might try alt.engineering.electrical and/or alt.home.repair where some
electricians hang out.

In general, your elec service should only be grounded once, at the main
panel, and subpanels need to tie back to that ground -- so there is no tie
bewteen the neutral and the ground in subpanels. If you have more than one
drop after the meter -- i.e., more than 1 "main" panel -- you are well
beyond me. Good luck.

simple answer, yes.

all the sub panels and sub sub panels should have the ground and neutral
isolate. this prevents "ground loops"

BRuce

William Hinshaw wrote:

This may be a little OT, but I sure could use some help. I've built a 12x24
multi-use shed, mainly intended to store my hardwood boards and increase
accessibility to those that always seem to be on the bottom. The wood racks
look great. In any case, I'm wiring it for lights, receptacles, exterior
lights and to feed power to a garden pump.

I have a Siemans breaker panel with a 100A main breaker installed. I would
like to have a main breaker handy in the shed. There are two vertical bus
bars which are presently connected by a removable insulated strap that
crosses the midline. One of these vertical bus bars has a green screw that,
if turned, will bond that bar (and the other one too if the strap is left in
place) to the metal case.

The connection to power, which once went to a panel in a mobile home now
replaced by the shed, arrives underground from the meter box (my meter is on
a pole remote from the house and I made the large temp panel there permanent
because the service is split there for several uses) in the form of *four*
insulated #4s: two hot wires, a neutral and a ground. These are controlled
by a 100A 220V breaker at the meter panel.

At the shed, am I supposed to isolate the neutral bus bar (by removing the
strap) and connect my neutrals all there and then ground the case with the
green screw and connect all my grounds to the now separate ground bus bar?
This would replicate the arriving connections and seems right to me, but
what do I know?

Any advice will certainly be appreciated.

Bill

William Hinshaw wrote:

At the shed, am I supposed to isolate the neutral bus bar (by removing the
strap) and connect my neutrals all there and then ground the case with the
green screw and connect all my grounds to the now separate ground bus bar?
This would replicate the arriving connections and seems right to me, but
what do I know?

Any advice will certainly be appreciated.

I *believe* from what you have described that you should
bond the ground and neutral together and provide an earth
ground rod at the entrance point to the shed. My understanding
of the NEC is that with sub-panels in detached outbuildings
you can use an entry-point ground rod for the outbuilding that
is not tied back to the main house ground. I think that is
what I would do in this case. Check with your local inspector
to be sure this is legit, though. And, do get this inspected.

Bill Ranck
Blacksburg, Va.