Unidentified burning smell - please help!

[bwall]

Hi,

I am very confused and hope someone can help. Twice in the last three days there has been a burning smell in our house. The first time the smell lasted for about 3 minutes and we think it came from our living room. This last time we think it came from our front room which is connected to the living room. It lasted about minute before the smell dissipated.

We are still trying to pinpoint the location of the smell and why and where. We don't think it came from any appliance. There are no visual signs of burning or smoke at all. We did have some electrical work done a about a month ago (they just capped some wires of some disconnected baseboards and disconnected them from the panel). We used a metal saw to cut out some metal of an old heating duct so that it could be drywalled over, which was also done about a month ago. Could this have jarred a wire loose and would that result in burning? The wires to the duct were not live but there is an active light switch in that wall (not close to where I cut but there was a lot of vibration).

Alternately, could it be something in our current HVAC system ducts (the duct referenced above was for our old electric baseboards which we replaced with the HVAC system about two years ago)? Those are the only two scenarios we can think of but we really have no idea. It smells of burning rubber or plastic so we are very concerned.

Any help, ideas, anything suggestions of what else to check for or tips on how/where to identify this would be much appreciated!!!

Thanks in advance.

Brad and Jen

[HayZee518]

burning smells are hard to track down. wirenuts are made of thermoplastic and hard plastic depending on make. IDEAL is hard plastic. Scotchlock is thermoplastic. Check the area within the switchbox. If the electrician just put the wires together and twisted on the wirenut, quite possible there's arcing inside the wirenut enough the heat the plastic and cause melting. SHUT THE BREAKER OFF THAT FEEDS IT FIRST, then go look. The switch body is hard phenolic so it would have to get really charred before you'd smell anything. If a dimmer switch is operating near its rated capacity it could be heating up its coverplate. dimmers rely on a lot of metal i.e. its yoke and the metal box to radiate generated heat. since the electric baseboards were disconnected that rules them out. you should remove the wiring as best you can between the panel and the heater locations. they make slugs to put in the knockout holes of the panel once you take out the romex connectors.

[normel]

Can you tie the appearance of the odor to the startup of the heating system? What type of heat do you have now? Are you sure the duct that was drywalled over was disconnected from the HVAC system? I would target the HVAC system first, either belts slipping or debris on the heating coils.