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#104459 - 02/27/03 07:50 AM Loose Connections Cause Fire Hazards  
Joe Tedesco  Offline
Member
Joined: Oct 2000
Posts: 2,749
Boston, Massachusetts USA
[Linked Image]

Loose connections and the load on the circuit created enough heat to cause this damage that could cause a serious fire.


Joe Tedesco, NEC Consultant

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#104460 - 02/27/03 08:34 AM Re: Loose Connections Cause Fire Hazards  
Electricmanscott  Offline
Member
Joined: Jan 2002
Posts: 1,457
Holden, MA USA
Ok you guys are going to hate me, but, would an AFCI have caught this?


#104461 - 02/27/03 12:15 PM Re: Loose Connections Cause Fire Hazards  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
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


Don(resqcapt19)

#104462 - 02/27/03 12:42 PM Re: Loose Connections Cause Fire Hazards  
mamills  Offline
Member
Joined: Nov 2001
Posts: 745
Wharton, Texas, USA
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).]


#104463 - 02/27/03 01:42 PM Re: Loose Connections Cause Fire Hazards  
RSmike  Offline
Member
Joined: Nov 2002
Posts: 134
Holland, MI USA
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


#104464 - 02/27/03 02:45 PM Re: Loose Connections Cause Fire Hazards  
wa2ise  Offline
Member
Joined: Nov 2002
Posts: 782
Oradell NJ USA
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.


#104465 - 02/27/03 04:07 PM Re: Loose Connections Cause Fire Hazards  
SvenNYC  Offline
Member
Joined: Aug 2002
Posts: 1,691
New York City
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.


#104466 - 02/27/03 04:10 PM Re: Loose Connections Cause Fire Hazards  
Joe Tedesco  Offline
Member
Joined: Oct 2000
Posts: 2,749
Boston, Massachusetts USA
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

#104467 - 09/10/05 06:33 AM Re: Loose Connections Cause Fire Hazards  
Joe Tedesco  Offline
Member
Joined: Oct 2000
Posts: 2,749
Boston, Massachusetts USA
Have any others that look like this one?

[Linked Image]


Joe Tedesco, NEC Consultant

#104468 - 09/10/05 09:07 AM Re: Loose Connections Cause Fire Hazards  
sandro2  Offline
Member
Joined: Mar 2005
Posts: 49
philadelphia,PA
Question about afci breakers. Do they detect in line arcs. Example when a load is turned on?


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