ok here's the situation.
arc-fault holds until i turn on the light switch. or turn on a lamp, basically it holds till any load is put on it (other than small alarm clock).

the particulars:
it is wired correctly.
Old knob and tube rewire.
it is in a the new service panel which is being fed by a jumper until the PoCo hooks up the new service. it is only feed by 3 wire (2phase and neut.) but there's Gr. Rods on both ends.
it's a Square-D arcfault, which they were having problems with earlier, these are supposed to be new ones. happens to all 3 arc-faults.


not sure if it has something to do with the arc-fault or the jumper between panels or what.
everything is wired correctly. it holds on a normal breaker forever, holds on the arc fault until any load is applied.

I love solving problems like these. I wish I was on site with you. It's a real challenge to figure out.

I will assume the AF breaker was changed with a new one to rule out a bad AF breaker.

I will also assume that NO knob and tube is controlled from this panel.

If so, sounds to me like a neutral touching the ground *somewhere* in the system. I don't doubt that your work was 'wired correctly', but unwittingly its possible when screwing in a receptacle or making a connection that the ground and neut. are touching.

I would start by going to the first receptacle being fed by the AF breaker and see if that ONE receptacle works ok. Apply power and load see if all is well. Then work your way down the circuit to the last recep.

IF you work your way through all the AF controlled receptacles and all is fine. Then I've seen ONE case where a receptacle NOT on the AF system had a neutral/grnd contact and cause the AF to trip.

If, after doing all of the above you still have problems, then I would wait for the PoCo to apply power to the new service to rule out the jumper issue.

I wish you the best, let us know how it goes.



[This message has been edited by Sandro (edited 12-15-2004).]

Either a neutral is touching the ground or more likely you have 2 circuits in 1 switch box and the install tied all the neutrals together.

There has been a major recall on square D QO arc faults, perhaps you got a bad one.

I had that prob in an old (1920's) house that was K&T. Turned out to be a couple of the Western Union splices that were buried within the ceilings. They weren't soldered and the twisting/wrapping got a bit loose after only 80 years. Fortunately these people wanted to redo the ceilings anyway.

I am going with Eagle on this one. Everytime I have had a problem with Arc-Fault breakers it has been a nuetral tied together.

Why are you even messing with those stupid things??? they arent even enforcing them around here till next year sometime...

i'm thinking my problem may be the remainging knob& Tube circuit that is still live at the moment, in the basement there's two lines feeding the same circuit. *rolls eyes* if ya unscrew fuse A 2 of the 3 lights in the upstairs drop out. if ya drop out fuse B instead all 3 lights go out..... quite a mess. glad it's a total rewire. knob and tube was a good safe system originally when unmodified and unadded too.