AFCI

[jafro]

I am an electrical inspector who ran accross an unusual situation involving an AFCI and non-AFCI bonding conductor interconnection. The last receptacle box on the bedroom circuit(AFCI)was use as a JB for a non-AFCI circuit dueto a damaged cable. The owner spliced the hot and identified conductor straight though but also connected all 3 bonding conductors together. when the AFCI is turned back on it trips. Isolating the AFCI bonding conductor from the non AFCI solved the problem.
Question: How does the bonding conductor get involved with an AFCI?

 

[jimwalker]

Re: AFCI

How can we have a non afci junction box in a bed room without calling it an outlet ?Is this fed from a non afci breaker ?That box to me is an outlet, so if it has a feed from a non afci breaker then it should not be there. What exactly are you saying ? he bonded what together ? the neutrals from the non afci circuit with those of the afci ncircuit ?

[ June 12, 2004, 03:09 PM: Message edited by: jimwalker ]

 

[tonyi]

Re: AFCI

A j-box with nothing that would draw current isn't an outlet. You could wallpaper a BR with'em and it would be OK.

Q: is the AFCI branch's neutral isolated from the non-AFCI one? If not, that would be a hardwired "instant-trip" situation the AFCI's GF aspect is going to trip on.

Even if the non-AFCI branch is leaking onto the (connected common) gnds, that leakage isn't something the AFCI device would see.

 

[bphgravity]

Re: AFCI

I'm under the assumption that some sort of cross connection between the ungrounded or grounded conductor was made.

The grounding conductor plays no part in the normal operation of the AFCI. Its just not possible for the EGC to cause the AFCI to trip unless you have unintentional contact with the grounded and grounding conductors in the box.

[ June 13, 2004, 09:43 AM: Message edited by: bphgravity ]

 

[jafro]

Re: AFCI

I will try to simplify the situation. Please put away all your NFPA and NEC and concentrate on the connections. The box in the bedroom IS a receptacle on an AFCI. Another cable (non AFCI) running in the same wall was damaged. He used the existing Receptacle(AFCI) in the wall as a junction box for the NON AFCI conductors. He spliced the hot and identified conductor (non AFCI)straight through. No connection to existing AFCI receptacle.No problem at this point.Power can be applied and all circuits respond as they should. NOW the bonding conductor from the AFCI circuit receptacle and the bonding conductor for the Non AFCI were connected together.AFCI trips when power is applied

 

[iwire]

Re: AFCI

jafro. Do I understand that what you are calling the bonding conductor is equipment grounding conductor, or forgetting about the NEC the 'bare' one?

The interconnection of two circuits EGCs should not by itself trip an AFCI, there has to be a connection between the 'white' and the 'bare' to have a problem.

 

[jafro]

Re: AFCI

You are correct. The AFCI circuit has a hot,neutral and a bonding conductor(incorrectly referred to as a ground wire)Black White and Bare. The non AFCI has the same

black------------------
white------------------ Receptacle (afci)
bare-------------------spliced to bare wire below

bare-------------------splice---------------
black------------------splice---------------
white------------------splice---------------
this afci trips when power applied to it

 

[iwire]

Re: AFCI

Right now under the NEC it is an Equipment Grounding Conductor, not a bonding wire although it would be nice if they called it that.

I am not following the rest of your post.

The EGC will have no effect on tripping.

 

[jafro]

Re: AFCI

One more try
Picture this:
A receptacle in a bedroom at the end of the circuit(last receptacle). This is supplied from an AFCI.
Now
Picture a new nmd cable (2 ends) is brought into this box since it was damaged and requires splicing.
The black and white are spliced properly but the bare wire was spliced in with the bare conductor from the arc fault circuit which are connected to the receptacle.
With these bare wires joined together the AFCI trips. Trust me it does trip.
Separate the bare wires and the AFCI does not trip

 

[iwire]

Re: AFCI

Originally posted by jafro:
The black and white are spliced properly but the bare wire was spliced in with the bare conductor from the arc fault circuit which are connected to the receptacle.
With these bare wires joined together the AFCI trips. Trust me it does trip.
Separate the bare wires and the AFCI does not trip

The interconnection of the different circuits EGCs will not trip the GFCI unless one of these EGCs is connected to a grounded conductor at some other place.

By your description you could not have two circuits in one metal box without tripping as the device straps tie the grounding together.

Trust Me

 

[jimwalker]

Re: AFCI

maybe someone could show a diagram of a gfci .I had trouble with them till i seen how they work.Now no problems

 

[jafro]

Re: AFCI

The question concerns an ARC FAULT CIRCUIT INTERUPTOR not a Ground fault Circuit Interuptor

The problem occurs when the ground wires are conected together NOTHING ELSE

 

[al hildenbrand]

Re: AFCI

Jafro,

The equipment ground wires (EGCs) should have no effect, connected to each other or segregated by branch circuit.

The tripping of the AFCI when the patched non-AFCI branch circuit EGCs are spliced to the AFCI branch circuit EGC clearly indicates, IMO, a neutral - EGC connection.

I submit that the AFCI EGC is open upstream from the j-box you have been describing and that the EGC that would float, normally, and test as a missing ground, is in contact with the AFCI branch circuit neutral.

A test for this would be to try to trip the AFCI with a 30 milliamp, or thereabouts, current from the neutral to the ground wire at the j-box you describe. If it doesn't trip, look for the EGC open and the EGC-neutral contact.

 

[bphgravity]

Re: AFCI

jafro, What your not understanding is that the responders here have determined from your description that the AFCI is most likely not tripping from an arcing event but from a small ground-fault. This is the only logical conclusion. Please read up on AFCI's, they do have a GFCI aspect to them.

When current flows out on the ungrounded conductor from the AFCI breaker, all that same current has to flow back on the grounded conductor connected the the same AFCI, save about 30mA. When you connect the EGC's together, there is obviously normal operating current flowing on one of the EGC's as it is probably inadvertently connect to a grounded conductor at some point. The sensor in the AFCI is picking up on this and causing the trip.

 

[jafro]

Re: AFCI

Thanks I forgot about the Gound Fault part of this breaker
jafro

 

[donnie]

Re: AFCI

Jafro, try giving this a thought, maybe the equipment ground that is joined to the non-afci circuit and the afci circuit is making contact with each other somewhere down stream on the non-afci circuit, I really don't think this would be the case, but some times strange things happens.