What's an Arc Fault breaker?
#1
03-10-02, 06:09 PM
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What's an Arc Fault breaker?
Okay, I understand single pole breakers, double pole breakers, and GFCI breakers, but this arc fault breaker is a new one me.
What's it do that's so special?
What's it do that's so special?
#2
03-10-02, 07:29 PM
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Well, here's what the NEC says: "An arc-fault circuit interrupter is a device intended to provide protection fromthe effects of arc faults by recognizing characteristics unique to arcing and by function to de-energize the circuit when an arc fault is detected."
The main purpose is prevent fires caused by malfunctions of cord and plug connected equipment (e.g., a frayed cord creating sparks that catch the curtains on fire). Existing circuit breakers are very poor at detecting this condition. A GFCI cannot detect most arcing either.
The National Fire Protection Association estimates that 40 percent of the fires that occur in residential dwellings can be attributed to arcing faults. This estimation is based on a study of insurance data with regard to fire origins in three states.
Other common situations that create arcing faults are pierced insulation on electrical construction wire, overheated cords or wires, and appliances where the insulation of the internal wires is impaired.
The main purpose is prevent fires caused by malfunctions of cord and plug connected equipment (e.g., a frayed cord creating sparks that catch the curtains on fire). Existing circuit breakers are very poor at detecting this condition. A GFCI cannot detect most arcing either.
The National Fire Protection Association estimates that 40 percent of the fires that occur in residential dwellings can be attributed to arcing faults. This estimation is based on a study of insurance data with regard to fire origins in three states.
Other common situations that create arcing faults are pierced insulation on electrical construction wire, overheated cords or wires, and appliances where the insulation of the internal wires is impaired.
#3
03-11-02, 04:00 PM
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Cool. I'm wondering about their theory of operation, tho. What's the signature of an arc fault that the breaker is able to detect and trip for?
#4
03-11-02, 04:20 PM
A quick google search reveals the following:
That was from here
-- Jim
"Arcing in a faulted AC circuit often occurs intermittently in each half cycle of the voltage waveform. The complex arcing event causes sputtering arc's that vary the current from normal load patterns. The precursor to the arc may be a high resistance connection leading to a "glowing contact" and then a series arc, or a carbon track leading to line-to-line or parallel arcing.
...
In a normal operating circuit, common current fluctuations produce signatures which must not be mistaken for an arc. Starting currents, switching signatures and load changes (normal or "good arc" events) are recognized in the AFCI as normal load signatures. Deviations or changes from these normal signatures are monitored by electronic circuits and algorithms to determine if arcing is occurring. When these arc-fault signatures are recognized, the circuit is interrupted and power is removed. "
...
In a normal operating circuit, common current fluctuations produce signatures which must not be mistaken for an arc. Starting currents, switching signatures and load changes (normal or "good arc" events) are recognized in the AFCI as normal load signatures. Deviations or changes from these normal signatures are monitored by electronic circuits and algorithms to determine if arcing is occurring. When these arc-fault signatures are recognized, the circuit is interrupted and power is removed. "
-- Jim
#5
03-12-02, 05:35 AM
Helpful for aluminum wiring???
I've read about these breakers before and it seems that they would be a great preventative measure for older homes that have aluminum wiring. I live in such a home, and while it's been partially rewired with copper, I still have several aluminum circuits. Most problems with aluminum wiring seem to be when the connections break down and arcing starts. These breakers would detect that and trip, possibly preventing a fire. Is my thinking on this sound?
#6
03-12-02, 06:50 PM
Arc fault breakers are a very very good idea especially in existing homes where you can find almost anything hidden in boxes and inside of walls. You can't make it more unsafe by using them. So in my opinion you have to be better than what you had for protection which was almost nothing regarding a method of registering arcing in a circuit.
There is a strong resistance and often times a don't push them on me attitude concerning arc fault protection. The 1999 NEC requires that arc fault breakers be installed protecting all receptacles circuits in bedrooms of new homes. I think this is just the start of what is going to be required in the future.
Many people in the industry are fighting the introduction of this arc fault breaker. Many are just fighting change. Many are questioning the ability of the arc fault breaker's sensing any arcing at all and are striking a show me attitude. Many are concerned that these arc fault breakers can not detect a series arcing. My opinion if they can detect a series arcing we are half way there.
UL and NEMA are stating that these arc fault breakers have been extensively tested.
Myself, I would spend the money. Right now you can find them at prices anywhere in comparison to a GFI breaker to rediculous prices. That is what we call fair trade? Check around and compare prices.
Sketchy, I am impressed. That was a good post you provided on arc faults
Hope this helps
Wg
There is a strong resistance and often times a don't push them on me attitude concerning arc fault protection. The 1999 NEC requires that arc fault breakers be installed protecting all receptacles circuits in bedrooms of new homes. I think this is just the start of what is going to be required in the future.
Many people in the industry are fighting the introduction of this arc fault breaker. Many are just fighting change. Many are questioning the ability of the arc fault breaker's sensing any arcing at all and are striking a show me attitude. Many are concerned that these arc fault breakers can not detect a series arcing. My opinion if they can detect a series arcing we are half way there.
UL and NEMA are stating that these arc fault breakers have been extensively tested.
Myself, I would spend the money. Right now you can find them at prices anywhere in comparison to a GFI breaker to rediculous prices. That is what we call fair trade? Check around and compare prices.
Sketchy, I am impressed. That was a good post you provided on arc faults
Hope this helps
Wg
