ECN Forum Forums Code Related Discussion NEC & other Code issues Multi wire circuits

sparky-

If my memory serves me correctly from the discusion about afci's, at least one company (i forgot which one) is making an afci for multiwire circuits.

Rojosy is right.
The 2P is required only on a single yoke in a residential multiwire outlet.

Why is everybody so afraid of the neutral (noodle ) connection? You make it hard just like the rest, and forget it...or fix it!
Anybody got a burnt up residential neut to report? (from a Code installed system)

Electure, I've only seen pre-main CB noodles go south, aluminum with no antioxidant is almost always the culprit. Good point.

CTwireman, Cutler Hammer is the only manufacturer of 2P AFCI CBs that I know of...

hi,
my question is WHY would you want to use a multiwire circuit in the first place? except for a 240V outlet. first, GFCI will not work on a multiwire circuit.

there has been a time or two that i would like to use a 3/C #12 to deliver two circuits to one area but if you every need a gfi down there you will need a seperate neutral.

i just think that its easy and safer to use a single circuit.

-regards

frodo

Frodo,

Once the 3 conductor cable is divided into 2 circuits there is no problem using GFCI Receptacles on them.

Sparky,

I just saw a CH rep at a local trade show and was assured several times that 2 pole (independant trip) AFCI Breakers are available. She gave me a cd with product information on it. I wasn't able to locate anything at the website, but here is some info from the CD;





Bill

[This message has been edited by Bill Addiss (edited 04-13-2002).]

Frodo,

For me, reducing voltage drop on long runs is a compelling reason to use a multiwire homerun.

Al

I don't have strong feelings about multiwire circuits. Except when they are not obvious. My nephew is fond of wiring power to switches and then to devices. Because of this he happened to run the lights and fan of a ceiling fan on 2 different circuits. A strange way to share a neutral. Despite the fact that the devices were not on the same "strap" I put a 2 pole breaker on the 2 circuits.

Voltage drop I do have feelings about.

I run a 50amp "multiwire" circuit to a subpanel and then put 2 wire circuits in. This keeps the voltage drop low. And keeps the wiring simple. (I figure a 50amp panel with 8-12 circuits will serve 625-750 sq ft.)

Redsy;
my bad, a local inspector wishes to update by insisting on 2-Pole's for all multiwires.

Bill,
interesting data, i was aware of the AFIT, but not the AFGF
can I assume the dif is the 4-6ma limit?

[This message has been edited by sparky (edited 04-14-2002).]

The problem with multi-pole CBs is that if lights are fed from the (MW) ckt. and a problem occurs on one leg, you're in the dark everywhere. Obviously this is more common in commercial & industrial facilities, but it's probably the main reason for the absence of a multi-pole CB requirement.

hi,
anytime i have ever tried to use a GFI that shared a neutral with another circuit the GFI trips.

how do you wire a 3 wire circuit with gfi's so that it will not trip? it works fine until you turn on a device on the OPPOSITE circuit. it may work if everything slaves of the gfi..?

as far as voltage drop and multiwire circuits goes, it is easier to use a number 10 than a number 12 than to install a multiwire circuit to account for voltage drop.

less time, less material, less confusion.

-regards

frodo