Wednesday, July 17, 2013

Blown in Foam Insulation - Should we be derating electrical wires running in it?

You see it in almost every new home and in some Commercial construction  a new style of blown in foam insulation  which totally seals off air leaks in homes and is an excellent energy saver. The problem thou is there is now no air movement around the romex wiring in homes walls which I worry could eventually result in fires when wiring overheats .

We saw a rash of these problems in the 1970's during the Carter Administrations  Energy Crisis when many home owners with homes which had no insulation got cellulose insulation blown into there homes walls and the result the Knob and Tube wiring which is designed to have air flow around it so a 14# gauge wire can be fused at 25 amps unlike Romex type wires which would have to be protected at 15 amps.

Overheated and caught homes on fire. So it finally became practice to d-rate wiring in these old homes and lower the fuse to 15 or 20 amps to prevent problems and add circuits and upgrade the services.

All electrical equipment is designed to have some air movement around it same way when we put wiring in pipe we must allow an airspace  as well to allow wires to expand  and this is what I worry about as you can see in the picture the entire electrical equipment is saturated with the foam theirs no expansion and no air flow.

I am not the only one worried I have talked with numerous fire officials , electricians and engineers etc. and all have concerns yet I have seen no action by any group or organization to look into this possibility. Guess where going to have to find out the hard way like we did with aluminum wire and plastic water pipes and flexible gas pipes   and then what about the hundreds of thousands of homes which already have this foam in place? Yes once again no one wants to look at this discuss or examine it till its too late what a dam shame there should have been plenty of research done on this before it was ever used. When I have concerns like this it usually proves true and as usual  I will be there saying I told you so.

1 comment:

  1. I never considered that my insulation could be a fire hazard. I know that insulation is flammable, but I thought that modern materials had minimized this risk. I can certainly understand how a lack of air circulation around an electrical wire is a problem. It is something that I will make sure to keep an eye out for.