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Joined: Oct 2000
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How much time/trouble would you say you spent installing AF on a service upgrade, or panel swap? Well that occured here back in the short era when it was just bedroom recetptacle circuits , before the ruling was overturned. Quite frankly the multiwires made it mission improbable, we tried to split them up, but you know how that goes I had more problems on renovation jobs trying to find afci's that fit older panels. There's more than a few older Challenger (for ex) panels around here with Siemens version 1.0 afci's in them , it became one of those things where the powers that be looked the other way for a while.....~S~
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Joined: Apr 2002
Posts: 7,382 Likes: 7
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Harold:
Yes, that's it.
Thank you, I was going to 'find' it in my files tonite.
Hopefully, the others here will check it out.
John
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Joined: Oct 2000
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for all appearances (key word) it seems they've improved...
~S~
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Joined: Jun 2006
Posts: 613
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I don't see AFCIs being very effective on any wiring system that does not include an EGC. It appears to me that most of the trips are from the ground fault circuit and not the fancy arc signature circuit. The GFP trips with a 30 to 50 mA fault, the arc signature circuit doesn't even look for faults with currents less than 5 amps. Ground fault protection works on ungrounded circuits so the EGC is not required but does improve the performance of GF devices. To my knowledge all GF detection works by totalling the current out and the current returning. they must add vectorallyl to 0 or within the trip setting of the device 6ma for GFCI and Usually 30ma for a GFI device. The series arc detection requires around a 5 amp threshold and arc signature. That may not have very much GF leakage and I suppose if the parallel arc detection is phase to phase you could be correct about not working without the arc signature. The fact that the current might travel through the studs or other path will activate the GF protection even without the EGC.
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Joined: Oct 2000
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well Mikesh, wouldn't UL1699's wording address this? (is there a linguist in the house?)clickyThe UL code states “By recognizing characteristics unique to arcing and functioning to de-energize the circuit when an arc-fault is detected, AFCI's further reduce the risk of fire beyond the scope of conventional fuses and circuit breakers. The UL page at http://www.ul.com/regulators/afci/ leads to details of how AFCI breakers are tested in the UL laboratory. The UL 1699 defines the requirements for the new AFCI breakers. Work on AFCIs by the UL can be traced back to a 15 March 1996 UL report of Research on Arc-Fault Detection Circuit Breakers which was based upon research that extends back into 1994. While AFCIs are specified to detect several different types of arcing faults, they will not detect all types of arcing faults, http://www.ul.com/regulators/afci/Dini.pdf. The UL 1699 Standard currently addresses four different types of arcing tests with different types of wires and insulation cuts, 15 different unwanted tripping tests, and 14 tests for overloads, short circuits, and mechanical operationanyone have an update on this? ~S~
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Joined: Nov 2000
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I don't see AFCIs being very effective on any wiring system that does not include an EGC. It appears to me that most of the trips are from the ground fault circuit and not the fancy arc signature circuit. The GFP trips with a 30 to 50 mA fault, the arc signature circuit doesn't even look for faults with currents less than 5 amps. Ground fault protection works on ungrounded circuits so the EGC is not required but does improve the performance of GF devices. To my knowledge all GF detection works by totalling the current out and the current returning. they must add vectorallyl to 0 or within the trip setting of the device 6ma for GFCI and Usually 30ma for a GFI device. The series arc detection requires around a 5 amp threshold and arc signature. That may not have very much GF leakage and I suppose if the parallel arc detection is phase to phase you could be correct about not working without the arc signature. The fact that the current might travel through the studs or other path will activate the GF protection even without the EGC. Mike, My point is that there is not likely to be a ground fault path on an knob and tube system and so there will be no 30mA ground fault trip. The AFCI will have to see the 5 amp series arc current before it can open the circuit. 5 amps is more then enough to make enough heat to start a fire. Glowing connections have occurred with loads of 100 watts or less. In a system/circuit with an EGC it is likely that the series fault will cause a ground fault long before AFCI arc detection circuit will see the problem. As far as 30 mA traveling through the studs or other non-metallic paths, I don't see that very likely in a typical dwelling unit.
Don(resqcapt19)
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