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All of the bedrooms in this house were on dedicated 12/2 runs. There were no multi-wire circuits in the house. Lighting not located in bedrooms were supplied by a seperate lighting circuit without arc-fault protection. No matter where a load was supplied in the home the master bedroom A.F.C.I. would trip. The problem turned out to be at the first served recptacle from the panel to the master bedroom. From that box, the electrician spliced the wires going to the next receptacle, at that splice, even though he had twisted the conductors, there was still one wire under the neutral wire nut that was slightly loose, thus causing the arc any time a load was applied. The only location that is common to this circuit and all other circuits in the house are at the neutral bus in the panel. All loads travel back to this location and out along all the other neutral conductors finding the weak connection in the master bedroom splice, arcing enough to trip that particular A.F.C.I. breaker.  Combination type A.F.C.I. breakers are required by the N.E.C. as of January 1 2008. Most jurisdictions have not enforced this reqirement due to the lack of availability. The required breakers are now slowly making their way to the supply houses and enforcement of this requirement can't be far behind. These breakers detect arc signatures in two ways, from and arc to neutral or an arc to ground, the arc signature that is causing the fault is then indicated by an L.E.D. light on the breaker. These breakers are presenly selling for about $35.00 each. Below is a great explaination of what these devices do from Bryan Holland, Secretary I.A.E.I. Florida Chapter. The current AFCI breakers are called branch circuit / feeder type afci devices. They function exactly like a typical breaker and include a component that can detect characteristics of an arcing condition and a component that functions much like a ground-fault protection of equipment device. (GFPE - NOT A GFCI) A GFCI protects humans, GFPE protects equipment. The arc sensing component is set at 75A. The GFPE component is set at 30mA (Class B gfci). It is this GFPE component that causes the breaker to open (trip) when an unintentional neutral to ground connection is made somewhere along the branch circuit. The arc sensing component is limited to PARALLEL faults only. In effect, this means that the branch circuit / feeder type afci device is incapable of sensing the arcing characteristics of those faults that are actually causing all the problems and fires. The new combination afci devices are now designed to detect these SERIES faults that are the real fire starters These series faults include glowing connections and arcing terminations. Basically, the device can now detect arcs occurring on one conductor rather than between two conductors or a conductor and a grounded object. The device still has the 30mA GFPE component; however the arcing component has been set down to 5A. They are much more sensitive. Much like GFCI evolution, afci's will go through several redesign periods over time. While the technology is not exactly new (Germany and South Africa have been using residual current devices (like an afci) since the 1980's), the 4 big breaker manufacturers seem to be having a real hard time getting a product out that meets the UL standard and operates as intended. Anyone and everyone involved in the electrical industry needs to get themselves a copy of the book, "Over current and Undercurrents - All about GFCIs, AFCIs, and Similar Devices" by, Earl W. Roberts. This book is absolutely fantastic and provides a comprehensive detail and discussion on electrical faults and the protection devices used to control them. | Return Home | Our Services | Employment | Code Violations | Prejects Past and Present | Useful Links | Whats New | Download Page | Arc Fault Issues | |
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