Scott, That appears to be a high resistance connection and not an arcing fault of any type. The AFCI device will trip for this type of fault only after the fault has progressed to a line to neutral, line to ground, or neutral to ground fault. It may or may not progress to a point where the AFCI will trip before the building is on fire. Will the AFCI have a better chance at detecting this fault before a fire starts than would a standard OCPD? Yes, it would. Don
Re: Loose Connections Cause Fire Hazards#104462 02/27/0311:42 AM02/27/0311:42 AM
An unusual looking receptacle. There are no screws to speak of (except for the EGC). It looks like what someone else here at ECN appropriately referred to as a "push and pray" type. I disected one of these receptacles to see just how much contact area was made between the #12TW wire I used and the contact points in the plug...appalling
[This message has been edited by mamills (edited 02-27-2003).]
Re: Loose Connections Cause Fire Hazards#104463 02/27/0312:42 PM02/27/0312:42 PM
Is it just me or does that green screw look a little loose?
I've never seen an outlet like this. NEC should start spec'ing a minimum contact area to eliminate device like this. I'm starting to see a lot of spring type wired devices that look really nice. They probably save a lot of time and $$. When I see pictures like this I have to reconsider their use.
So I have a 12AWG plugged into the back of this with some spring terminal that engages the wire on maybe one side with only a small amount of surface area. Then I plug in my 12AWG cord from my wall AC unit. Right! I love the smell of plastic burning in the morning.... smells like... Er...uhm....UL listing?
Isn't it like running 1" water pipe, dropping down to 1/2" and then going back to 1".
Re: Loose Connections Cause Fire Hazards#104464 02/27/0301:45 PM02/27/0301:45 PM
Isn't this one reason the code requires electrical boxes? To contain failures like this so it doesn't set the house on fire. As I understand it (I'm one of those infamous electrical engineers) the NEC code is written such that, if complied with, a single failure like the above will be caught before it leads to a bigger failure (like the house burning down). Layers of redundancy, to improve safety.
Re: Loose Connections Cause Fire Hazards#104465 02/27/0303:07 PM02/27/0303:07 PM
This picture shows a receptacle with burned off contacts, and it was on a display table at one of my seminars.
Yes, the EGC was loose, and the use of 12 AWG is no longer permitted for the "push-in" types of connections.
I believe that UL stopped listing that product quite some time ago. The use of a box for enclosing a receptacle is usually the way in which it gets installed. A box does help to keep the "fault" contained within the box, that's why we have certain rules that limit open gaps and flush .... etc.
Joe Tedesco, NEC Consultant
Re: Loose Connections Cause Fire Hazards#104467 09/10/0505:33 AM09/10/0505:33 AM