On Thu, 19 Apr 2007 16:12:34 -0400 snipped-for-privacy@aol.com wrote: | On 19 Apr 2007 15:04:59 GMT, snipped-for-privacy@ipal.net wrote: | |>On Thu, 19 Apr 2007 08:34:21 -0500 Bud-- wrote: |>
|>| A GFCI trip suggests the air compressor has hot-to-ground leakage. |>
|>Or it could have neutral to ground leakage. If the neutral and ground |>are connected together at the load, the return current will split between |>those wires, and the GFCI will not see the same current level between hot |>and neutral. In either case, the compressor is defective and dangerous |>for use. It needs to be repaired or replaced. |>
|>
|>| Brush motors are not supposed to trip AFCIs. AFCIs almost always include |>| a 30 mA ground fault trip (GFCIs use 5 mA). It is possible the shop vac |>| has hot-to-ground leakage. If you plug the shop vac into the GFCI does |>| it trip? Do you have more than 1 AFCI - trip the others also? |>
|>There is a history of some AFCIs being overly sensitive, or some motor |>loads having excess brush arcing, and tripping AFCIs (and not GFCIs). |>The OP should test the shop vac on a GFCI. If it is OK on a GFCI, then |>the AFCI should be returned to the manufacturer for evaluation (but they |>will likely also need more information to reproduce the problem, if not |>the actual shop vac). And the shop vac could be defective and have a |>kind of fault, or excessive arcing, that the AFCI should detect. | | | Most AFCI trips get traced back to ground/neutral faults. That is | where the ceiling fans got that bad reputation. It was usually that | big cludge wirenut vibrating into the hickey when the fan was running. | The original AFCI designs (for the arc fault part) were only looking | for short duration current spikes in the 70a+ range. They just detect | dead shorts from line to neutral. The GFCI protection was added to | find shorts from neutral or line to ground at the 30ma level.
That's not what some aspects of what I read say. There have been documents (I didn't keep them handy) that described "series arcs" as arcs due to a loose connection that isn't a short circuit path. The arc transients would therefore have no more increase than what the load is, plus or minus any circuit/load reactive components affecting it.