I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

Perce

On Mon, 27 Nov 2006 13:22:49 -0500, "Percival P. Cassidy"
wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

I didn't think you could make a GFCI outlet work
on an edison circut.

On 11/27/06 01:59 pm Goedjn wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

I didn't think you could make a GFCI outlet work
on an edison circut.

Doh! Of course you are correct. What was I thinking!?

OK, scrub #1. What about the others?

Perce

"Percival P. Cassidy" wrote in message
...
On 11/27/06 01:59 pm Goedjn wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

I didn't think you could make a GFCI outlet work
on an edison circut.

Doh! Of course you are correct. What was I thinking!?

OK, scrub #1. What about the others?

Interesting! You dropped the only one that made sense. Assuming an Edison
circuit is the same as a multiwire circuit, the outlets don't know what they
are on; the neutral current is only reduced when the two branchs come
together; so anything on the common neutral will not work, but anything on
the split neutrals will work fine.

Percival P. Cassidy wrote:
On 11/27/06 01:59 pm Goedjn wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected,
but I am wondering which is the best way to do this, both from the
NEC point of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?


I didn't think you could make a GFCI outlet work
on an edison circut.


Doh! Of course you are correct. What was I thinking!?

OK, scrub #1. What about the others?

Perce

I can't think of any technical reason why a GFCI "outlet" would not work
on a shared neutral circuit.

The detection of a ground fault is done by noting imbalanced currents in
the hot and neutral leads of whatever's plugged into the receptical, and
that takes place entirely withing the receptical. The sensing of a
neutral to ground fault is similarly done within the receptical.

If I'm wrong about that I'd appreciate learning why.

I'd try it and see.... I prefer using GFCI outlets because when they
trip it's pretty certain there IS a true ground fault in whatever is
plugged into them, and not just a little too much condensation inside
some junction box or bathroom exhaust fan.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

On Mon, 27 Nov 2006 13:22:49 -0500, "Percival P. Cassidy"
wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

Perce

IMHO:

Unless they sell a double pole GFCI breaker(for the shared neutral) I
think you only option is #1. P.S. I think this type of breark (#4) is
expensive if it exists.

The shared neutral(guessing you are doing something like 14/3 or 12/3
circuit) means that #2, #3 aren't feasible.

You can splt the neutral and feed seperate GFCI receptacles, and each
GFCI receptacle.

Now this is just guessing, since I can't actually see what you are
doing.

later,

tom

On Mon, 27 Nov 2006 13:59:11 -0500, Goedjn wrote:

On Mon, 27 Nov 2006 13:22:49 -0500, "Percival P. Cassidy"
wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

I didn't think you could make a GFCI outlet work
on an edison circut.

You can. Just connect them AFTER you separate the neutrals.
--
28 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Mon, 27 Nov 2006 14:30:27 -0500, Jeff Wisnia
wrote:

Percival P. Cassidy wrote:
On 11/27/06 01:59 pm Goedjn wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected,
but I am wondering which is the best way to do this, both from the
NEC point of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?


I didn't think you could make a GFCI outlet work
on an edison circut.


Doh! Of course you are correct. What was I thinking!?

OK, scrub #1. What about the others?

Perce

I can't think of any technical reason why a GFCI "outlet" would not work
on a shared neutral circuit.

The detection of a ground fault is done by noting imbalanced currents in
the hot and neutral leads of whatever's plugged into the receptical, and
that takes place entirely withing the receptical. The sensing of a
neutral to ground fault is similarly done within the receptical.


Some people don't seem to recognize the difference between a shared
neutral on the LOAD side of the GFCIs (won't work) and a shared
neutral on the LINE side of the GFCIs (no problem).

If I'm wrong about that I'd appreciate learning why.

I'd try it and see.... I prefer using GFCI outlets because when they
trip it's pretty certain there IS a true ground fault in whatever is
plugged into them, and not just a little too much condensation inside
some junction box or bathroom exhaust fan.

Jeff
--
28 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

On Mon, 27 Nov 2006 13:22:49 -0500, "Percival P. Cassidy"
wrote:

I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

Perce

Both #2 and #3 sound impossible (with a shared neutral). There would
be no way to connect the neutral properly. You would be unable to use
more than 1 outlet at a time.

I think #1 is best.
--
28 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

Mark Lloyd wrote:
On Mon, 27 Nov 2006 13:22:49 -0500, "Percival P. Cassidy"
wrote:


I am planning to put two adjacent outdoor duplex outlets on an Edison
circuit (shared neutral). Obviously they should be GFCI protected, but I
am wondering which is the best way to do this, both from the NEC point
of view and from a convenience point of view.

The three options I see a

1. Two separate GFCI outlets -- the cheapest solution, AFAICS.

2. Two separate GFCI breakers.

3. Ganged GFCI breakers (separate breakers with a handle tie -- if
available for Cutler-Hammer CH)

4. 2-pole GFCI breaker -- probably the most expensive solution.

Have I missed any? Which would be best?

Perce


Both #2 and #3 sound impossible (with a shared neutral). There would
be no way to connect the neutral properly. You would be unable to use
more than 1 outlet at a time.

I think #1 is best.

Ayup, with a shared neutral, there's no way to use a GFCI breaker
because the GFCI works by comparing hot and neutral current. You need
GFCI outlets installed after the point at which the two circuits diverge.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Maybe one way to discuss this is;

1) Suppose that you have an 'edison' (split) outlet. Assume for the
moment it is, say, inside the house.

2) Beyond, i.e. further downstream of that, and for use outside, you
install two duplex GFCI outlets. One of them uses one of the 120 v legs
and the neutral. The other uses the other leg and the neutral. The
neutral splitting 'before' going separately to each GFCI. The neutral
cannot 'go through' one GFCI to reach the other.

3) Anything plugged into either of the GFCI which causes an unbalance
of the neutral and live wire currents flowing to/from that outlet will
cause it to trip and protect. The other GFCI will not trip.

4) Even if one or both of the GFCI operate, the edison outlet will
still be fully live on both parts of its split personality. In fact
after installing the two GFCI you could eliminate it! Or not install it
all in the first place?

Assuming the edison arrangement and two GFCI outlets are needed because
of an expected larger load than the 15 amps that can be drawn from a
single duplex outlet (GFCI or otherwise)? If not one (non edison) GFCI
outlet could be installed and a 'regular' outlet downstreamed from
that! Both would be protected by the single GFCI.

BTW I came across an older GFCI of the type that does not allow another
outlet to be downstream of it. So installed it in a metal box at the
end of an older but substantial extension cord. This provides a GFCI
protected circuit no matter where plugged in; for example can be
plugged inside the house into a regular non GFCI outlet and run out
through a window to work on something outside.