AFCI Woes

sparky_magoo · Sep 30, 2005

I made up a panel today and realized a huge mistake. From the panel, I have conduits run under the slab, to junction points.

I have a conduit to the master bath which terminates in a 3 gang masonary switch box. I ran a multi-wire ckt. to this box to power the master bedroom receptacles and the master bath GFI ckt. My question is, how can I possibly power an AFCI breaker for the master bedroom ckt. with a shared nuetral on the master bath GFI ckt. The owner of my company told me to do it this way, but I feel it is my responsibiliy to detedt any incompetance and correct it before any wire is pulled.

Can I make this ckt. work? Wouldn't unbalanced current from the GFI ckt. cause the AFCI breaker, for the bedroom, to trip? This is a long pipe run. I would have to pull all of the wires out and re-pull with an additional nuetral conductor. I am already maxed on pipe fill.

Does anyone make a 2 pole AFCI breaker? This is a CH commercial panel (22' wide, forty slots).

BTW, are CH AFCI breakers listed for use in a commercial panel? I am new to this shop. I am not used to their ways. Running conduit under the slab to feed branch ckt.'s is new to me.

al hildenbrand · Sep 30, 2005

Re: AFCI Woes

CH makes a selection of double pole BR breakers.

Does this panel accept BR breakers?

peter d · Sep 30, 2005

Re: AFCI Woes

You may have to mount a small "sub panel" on the side to accomodate the AFCI's.

But we need more info about this "commercial panel." Is it plug-in? Bolt-on? Type BR? Type CH?

jwelectric · Sep 30, 2005

Re: AFCI Woes

I am confused by your statements as outlined below

I have a conduit to the master bath which terminates in a 3 gang masonary switch box. I ran a multi-wire ckt. to this box to power the master bedroom receptacles and the master bath GFI ckt. My question is, how can I possibly power an AFCI breaker for the master bedroom ckt. with a shared nuetral on the master bath GFI ckt. The owner of my company told me to do it this way, but I feel it is my responsibiliy to detedt any incompetance and correct it before any wire is pulled.

If the wire is already pulled in the conduit simply reinstall but if the second part of your statement is correct then simply pull the right amount.

It is in conduit from panel to three gain is this correct?

sparky_magoo · Sep 30, 2005

Re: AFCI Woes

Thanks for the replies. I was going to bring home the part number of the panelboard and forgot. It is 22" wide. It's a 200 amp service. 40 slots. My main question is, how can I make AFCI breakers work on multi-wire ckt.'s. I believe the unbalanced current on the nuetral will trip the GFI portion of the AFCI breaker.

sparky_magoo · Sep 30, 2005

Re: AFCI Woes

Re-pulling would ba a drag. It is 160 feet of PVC with many bends. I would have to pull the whole mess out of the pipe and re-pull with the second nuetral conductor into an already over-loaded pipe.

BTW, The conduits were run under the slab before I was hired. The guy who did the pipes under the slab was fired for failing a drug test.

al hildenbrand · Sep 30, 2005

Re: AFCI Woes

A double pole AFCI watches both hots and the neutral simultaneously.

The GFI portion works the same way any plain old double pole GFCI works.

al hildenbrand · Sep 30, 2005

Re: AFCI Woes

Tag,

Yer it!

sparky_magoo · Sep 30, 2005

Re: AFCI Woes

I have never seen a double pole AFCI CH breaker. Are they really made? Since AFCI's are only required in residential bedrooms, why would CH make one. Can any of you guys point me to a website where I can find one. Has anyone ever used a CH 2 pole AFCI breaker before? Does this breaker really exist? Please give me a link to Cutler-Hammer's website where I can spec. a 2 pole AFCI breaker to my boss.

sparky_magoo · Sep 30, 2005

Re: AFCI Woes

Al, I think you are on the money. I inherited this project and blew it on not realizing that I can't make multi-wire ckt.'s on AFCI ckt.'s. My boss told me to do this, but I see it as my problem.

al hildenbrand · Sep 30, 2005

Re: AFCI Woes

Take a look at CH Product Index and select Arc Fault Circuit Interrupters near the top of the first column.

Edit a typo - Al

[ September 30, 2005, 11:54 PM: Message edited by: al hildenbrand ]

George Stolz · Oct 1, 2005

Re: AFCI Woes

I know this might sound really really dumb, but can you pull in a romex homerun to the bedroom?

Are you in Chicago or something? Why the pipe?

A whole 'nuther problem to boot, that Bath GFI circuit. Ug.

sparky_magoo · Oct 1, 2005

Re: AFCI Woes

I can't explain the pipe. When we do houses on slabs, the owner likes to run PVC under the slab and stub up in "strategic" locations. Form the stubs, I smurf up into 4/11 receptacle boxes (with 1 G rasied covers), switch boxes, or J-boxes hidden in closets.
I then run Romex to the boxes and splice. The owner feels this is a better way of doing things. I hope he doesn't read this forum, because he would know who is talking about him.

sparky_magoo · Oct 1, 2005

Re: AFCI Woes

The bath GFI should be fine. The GFI receptacle will be located downstream from the shared nuetral.
I have successfully done this before.

normbac · Oct 1, 2005

Re: AFCI Woes

?? why pull all wires out instead of tying 2 neutrals to your existing neutral and pull that?? with plenty of lube 10 minutes problem solved

al hildenbrand · Oct 1, 2005

Re: AFCI Woes

Sparky,

From your description so far, the only "problem" that I am picking up is the cost of a double pole AFCI. But that's the owner's responsibility. It sounds like you've asked the right question. . .whether the multiwire homerun needs to have seperate neutrals or not. As long as a double pole BR or CH AFCI is installed, the existing shared neutral of the multiwire homerun is not a problem. If your boss gives you two single pole AFCI's, ask for the double pole, or the permisssion to repull the raceway. Your boss will figure it out.

Go to the link I posted for CutlerHammer in my post above and read the product literature. The links to the product literature are on the Arc Fault Circuit Interrupter page. There are

Application & Product Overview
Selection Guide
Specifications
Technical Data
Installation Manuals
Online Catalog

Curiously, even though the list includes "Installation Manuals", there are none at that link. Look at Specs and Selection and the rest of them.

don_resqcapt19 · Oct 1, 2005

Re: AFCI Woes

I would have to pull the whole mess out of the pipe and re-pull with the second nuetral conductor into an already over-loaded pipe.

If your conduit it so full that you can't add an additional conductor, I would expect that you would also have an issue with the conductor ampacity after the required derating for more than 3 conductors in a raceway.
Don

jimwalker · Oct 1, 2005

Re: AFCI Woes

What stage are you in right now,rough or trim ?

sparky_magoo · Oct 1, 2005

Re: AFCI Woes

De-rating isn't an issue. I ran #8's for the 20 amp. ckt.s The pipe is almost 120' long.

The house hasn't been rocked yet and the plumbers aren't done.

Since the owner told me to use multi-wire ckt.s, perhaps he is plannig on using two pole AFCI breakers.

edited to correct spelling.

[ October 01, 2005, 09:01 PM: Message edited by: sparky_magoo ]

George Stolz · Oct 1, 2005

Re: AFCI Woes

Originally posted by sparky_magoo:
The house hasn't been rocked yet and the plumbers aren't done.

Man, I would so be pulling a new romex home-run right now. Those breakers are way too expensive to consider if the place isn't rocked yet.

Since the owner told me to use multi-wire ckt.s, perhaps he is plannig on using two pole AFCI breakers.

Perhaps he thinks he's the king of France. Either he's nuts or you misunderstood what he told you to do. I'd definutely ask him before proceeding.

T&M or not, you're looking at one irate customer when he gets a bill for a $200 (more like $300 to him!) circuit breaker when $20 worth of romex would have done the trick.

AFCI Woes

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