ECN Forum Forums General Topics of the Trade General Discussion Area It was Electrical

Just a minor nitpick, but if a ground fault caused a fire with pre-1959 BX, it was most likely inductive reactance more than resistance (although resistance probably did contribute). The old BX tended to conduct the bulk of fault current in the spiral path of the armor, which caused a choke effect. The post-1959 stuff has that little 14 AWG aluminum strip in it, obviously too small to properly conduct fault current on its own, but it makes continous contact with the armor, reducing the choke effect. The old BX often imposed a high impedance on fault current, and this resulted in numerous fires, since a ground fault that should otherwise trip a breaker or blow a fuse would not do so.

This is the reason why runs of flexible metallic conduit exceeding six feet must have a separate EGC, as per 250.118(6)c.(2002 NEC).

In my area, we don't use Type AC cable. We are required to have a separate copper EGC for all wiring methods. Therefore, you see a lot of MC cable around here.

I'm still amazed any cause can be found when a house burns down like
this

Ian A.

[This message has been edited by Theelectrikid (edited 02-01-2007).]

Just to show the difficulty that fire investigators go through right now the Manitoba Fire Commissioners office is investigating a fire that resulted in the death of two 30+ year fire captains and injured 4 fire fighters.

Its in the -30°C range right now with the wind chill and the City Of Winnipeg public works department assigned a waterworks steam truck Tuesday to assist the fire investigators thaw out the rubble so they can sift through it.

It does not help the pressure the investigators are under with some of the Winnipeg media saying that their "sources" say that the fire started in the attached garage where the electrical is.

All that's known right now is there was a second floor flash over that was hot enough to melt the portable radio assigned to one of captains.

For any of the firefighter members of ECN that want to find out more the Winnipeg Fire Union page has current information at http://uffw.ca/current_events.htm

I think most of the fire halls in British Columbia have their Flags at Half Mast.

mbhydro:

Sorry to hear about that loss of life..many folks don't know how dangerous firefighting really is. Fire can turn on you in a heartbeat. I have a lot of respect for those in the profession.

On Thursday morning, a neighbor's house caught fire. It originated in the front bedroom and was detected by the resident of the other half of the duplex. Luckily the heaviest damage was confined to that bedroom, the FD had to make only one penetration into the roof (a small one at that) and it was knocked down very quickly. A lot of that good fortune was due to the fact that the FD here is only a few blocks away.

The cause? Overloaded receptacle in that bedroom. This one was definately electrical. The poco disconnected that unit as there was further wiring damage in the attic.

I spoke very briefly with the resident, she was unhurt and grateful that only "things" were lost, no injuries or life lost.

I may talk with her again and if she agrees I will get photos of the damage.

Good Lord mbhydro,
My thoughts and prayers go out to the families of the people involved in that incident.
The loss of experience like that can never be recovered.
Cruel that the higher ranked staff lost thier lives.
Not good at all.