ECN Forum Forums General Topics of the Trade General Discussion Area AFCI's and At Home Dialysis Equipment.

I'm curious why air conditioners are the target for LCDI protection. From what I can find so far on these, it's just for fire protection. But don't see how air conditioner cords have a monopoly on causing fires.

From years as a firefighter, I have seen many fires caused by window units. Mostly at the plug. I have also seen many fires caused by space heater cords. Lots of window units and space heaters are used in older homes with substandard wiring. These are often plugged into extension cords not rated for the current. NFPA uses fire reports filled out by the fire dept. to develop codes and standards. With a AC unit, the fire was caused by electrical short in the unit. With a space heater , the fire was caused by the heater. There is little effort ether by the fire dept, NFPA or others to determine the exact cause. I can say by my experience that many space heater fires were caused by extension cords and poor connections (plug strips & multi plug adapters) rather than the use of the heater itself. (near combustibles or tip over ) Most firefighters and arson inspectors are NOT forensic electrical inspectors and do not detail the cause of the fire in the report. Robert

I am not sure how a dongle on the cord can protect from problems on the line side of the cap.

It cannot. Although LDCI are required now, most fires and overheating I saw were at the cord cap. Most newer AC units pull far less current than the older units. I have a new unit I have for use after hurricanes. It is 8000 btu and pulls 5.2 amps full load. I have a customer has the same size unit but its 15+ years old, it pulls 12a When I wrote fire reports that were sent to the state and NFPA, when a AC unit was involved and it involved a cord or plug, it was just marked AC cord. I am not saying LDCI are not a good idea, just that from personal experience, I saw few cord fault caused fires. I do know the NFPA encouraged fire dept. to be as detailed in their reports as possible to help them develop codes to prevent fires. Trouble with this is few firefighters have much if any electrical know how so only general information is put on the fire reports. I have read many fire reports that said "short in AC cord " when in fact the cord cap melted.

I suspect these problems are more related to worn out 40 cent receptacles than anything. I know my wife burned up a vacuum cleaner plug in this house shortly after we moved in. The receptacle in the living room was burned too. I ended up buying spec grade receptacles and doing them all. After that I went over and did all my Mom's receptacles and switches too.
Maybe what they really need is a thermal cut out in the plug.