ECN Forum
Posted By: Joe Tedesco Loose Connections Cause Fire Hazards - 02/27/03 11:50 AM
[Linked Image]

Loose connections and the load on the circuit created enough heat to cause this damage that could cause a serious fire.
Ok you guys are going to hate me, but, would an AFCI have caught this?
Posted By: resqcapt19 Re: Loose Connections Cause Fire Hazards - 02/27/03 04:15 PM
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
Posted By: mamills Re: Loose Connections Cause Fire Hazards - 02/27/03 04:42 PM
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 [Linked Image]

Mike (mamills)

[This message has been edited by mamills (edited 02-27-2003).]
Posted By: RSmike Re: Loose Connections Cause Fire Hazards - 02/27/03 05:42 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".

RSlater,
RSmike
Posted By: wa2ise Re: Loose Connections Cause Fire Hazards - 02/27/03 06:45 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.
Posted By: SvenNYC Re: Loose Connections Cause Fire Hazards - 02/27/03 08:07 PM
Re: electrical boxes containing failures

That's an interesting comment and I can see where it would work with a metal box.

However how would a plastic box contain a flareup like that? Plastic melts and sometimes burns.

Are plastic device boxes made of a fire-retardant material? I'm not too familiar with them...have always dealt with and seen metal boxes only.
Posted By: Joe Tedesco Re: Loose Connections Cause Fire Hazards - 02/27/03 08:10 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.
Posted By: Joe Tedesco Re: Loose Connections Cause Fire Hazards - 09/10/05 10:33 AM
Have any others that look like this one?

[Linked Image]
Posted By: sandro2 Re: Loose Connections Cause Fire Hazards - 09/10/05 01:07 PM
Question about afci breakers. Do they detect in line arcs. Example when a load is turned on?
Posted By: iwire Re: Loose Connections Cause Fire Hazards - 09/10/05 01:26 PM
Sandro welcome to the forum.

Check out these links and you can add to one or more of these threads. I suggest the third link on the list to start.

https://www.electrical-contractor.net/ubb/Forum1/HTML/001120.html
https://www.electrical-contractor.net/ubb/Forum1/HTML/001167.html
https://www.electrical-contractor.net/ubb/Forum1/HTML/001651.html
https://www.electrical-contractor.net/ubb/Forum1/HTML/003370.html
https://www.electrical-contractor.net/ubb/Forum2/HTML/000043.html
https://www.electrical-contractor.net/ubb/Forum2/HTML/000352.html
https://www.electrical-contractor.net/ubb/Forum4/HTML/000140.html

Bob

[This message has been edited by iwire (edited 09-10-2005).]
Posted By: cpalm1 Re: Loose Connections Cause Fire Hazards - 09/12/05 01:21 AM
"Isn't it like running 1" water pipe, dropping down to 1/2" and then going back to 1"."


yes, excep for the fact that a 1/2 water pipe won't burn you house down.

of course, too small of a water pipe could put a damper on your ability to extinguish the fire [Linked Image]
© ECN Electrical Forums