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Discussion Starter #21
BTW, if you put a GFI receptacle in and use it to protect additional receptacles, wouldn't you have to daisy chain then? Seems like I remember that was the only time I daisy chained.
yeah in the case of a GFCI you would use both terminals as line and load for it to detect the current difference.
 

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Electrician
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265 Posts
Overload? If those conductors are protected by the proper size OCPD and the connections are tight, how would an overload cause that damage? That picture looks like a classic loose connection. And feeding 20 amps through the terminal screws of a 15 or 20 amp receptacle will not cause any problems, that is why the practice is not prohibited by the NEC.
 

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Discussion Starter #23
Overload? If those conductors are protected by the proper size OCPD and the connections are tight, how would an overload cause that damage? That picture looks like a classic loose connection. And feeding 20 amps through the terminal screws of a 15 or 20 amp receptacle will not cause any problems, that is why the practice is not prohibited by the NEC.
the connections were definitely tight on 4 of the 5 terminals. The other one as I stated I started to unscrew myself before the picture was taken, but just said screw it after the whole terminal was somewhat moveable on the melting frame, and I just cut the wires. It might have been somewhat loose possibly, but it appeared to be screwed down tight on the wire at the time. In the picture though, yes that terminal has been loosened.

There is the possibility of overload, as it was not a heavy duty grade receptacle. It was a cheap 15 amp receptacle on a 20 amp OCPD (was 12 wire though), daisy-chained sharing the entire load of everything (and then some that shouldn't have been on that circuit) down the line.

God knows how old the breakers are, who's to say they'd actually trip either - there could have been more than 20 amps flowing through that. In theory the wire is rated for up to 30, but that receptacle is not. Regardless though, problem solved... new wire, quality receptacles and a AFCI breaker
 

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Head Grunt
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3,270 Posts
Loose wires cause fires. When you see a receptacle all melted like that, it was just a loose connection that declared itself. It might just be an illusion, but the offending conductor seems to have been backstabbed and not wrapped around the screw. Was that the case?
X2, any time i have found a melted rec in a home it was due to loose connections and not excessive load. I found one once behind a dresser that had actually caught fire and the flames had singed the wall and back of the dresser about three feet up. Both power and neutral were loose on that one.
 

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Low Voltage Contractor
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98 Posts
Thanks man.

I need to post a thread asking about twisting wires before you put a wire nut on. I was taught you always do. But I see many electricians who don't and a few who do.

BTW, if you put a GFI receptacle in and use it to protect additional breakers, wouldn't you have to daisy chain then? Seems like I remember that was the only time I daisy chained.

Anyways, thanks for chatting. I like knowing why you guys do what you do. Especially because I have some of it in my background.

My start was rough. I got a copy of the NEC and studied it like crazy because I wanted to do it to code even if no code was enforced. So the electrical forum intrigues me.
When I started out doing residential remodel work the electricians I worked under never used their linemans to twist the wires together before putting the wirenuts on. This was because they were in a hurry to get the splices done, covers on and out of the attic. Aside from adding dedicated circuits, they never shut down the circuit they were working on at the panel because they didn't want to inconvenience the homeowner and it would require multiple trips into the attic. They even showed me how to test whether a circuit was switched or not while up in an attic and found that you had forgot your voltage tester...with your finger!! Such a stupid practice. When I went to work for a commercial electrician I was shown the right ways and the importance of twisting the wires before putting on the wirenuts, and to make sure no copper is seen under the wirenuts. It's easy to think that all is good once you put push the wires back into the box and put that cover on. Double check them and you'll sometimes find a wirenut is just barely on. A little heat through those wires could cause them to dump that wirenut and contact something else, or loosen up and arc.

Nothing wrong with daisy chaining them, but the GFCI has to be first in the series in order to protect the other receptacles.

-Chilla
 

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Low Voltage Contractor
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Loose wires cause fires.
An important fact espoused by AC/DC(the band not the current)

"Loose wires cause fires
Gettin' tangled in my desires, so
Screw 'em up and plug 'em in
Then switch it on and start all over again
I'm gonna get it up
Never gonna let it up, no
Tickin' like a time bomb, oh yeah
Blowin' out the fuse box"

-Chilla
 

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1. Pretwisting wires is only as good as the prewisting. I have seen many prewisted connections where the twist is bad & the wirenut is loose. ( Something about the boss did it 50 years ago, big deal). I will put my un prewisted connections againist your prewisted ones! I never said I did 'um loose. Oh, TRY to pretwist stranded!

2. The Code specifically states that all parts of a circuit must be rated for the circuit amps.

3. There is an exception that states that a 15A receptacle may be installed on a 20A circuit. BUT THE RECEPTACLE CAN NOT BE PART OF THE CIRCUIT!!!! Thus NO FAST TAPPING THE PLUGS!! Under the screws counts as fast tapping. Pull 20A through a 15A plug, well IT'S GOING TO MELT! The 15A GFCI's are rated for 20A through them.
 

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Peon
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131 Posts
You can't overload a receptacle that has the proper wire size and proper sized current protection in place, at least for more than a moment or two.

That problem is likely a loose wire; screw not tight or loosened when the wires were folded back into the box. Either way too loose.

Could also be a loose contactor inside the recept that grasps the plug. That would transfer the heat to the screw base. I'm assuming the recept is CU and not AL, like the wires, but can't really see.

When I saw the topic I expected to see a recept with the push-in connections. I NEVER use them. I've seen several meltdowns from them and I'd bet they caused many house fires. They shouldn't be allowed.
 

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Baltimore Electrician
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1,249 Posts
1

3. There is an exception that states that a 15A receptacle may be installed on a 20A circuit. BUT THE RECEPTACLE CAN NOT BE PART OF THE CIRCUIT!!!! Thus NO FAST TAPPING THE PLUGS!! Under the screws counts as fast tapping. Pull 20A through a 15A plug, well IT'S GOING TO MELT! The 15A GFCI's are rated for 20A through them.
Incorrect. the only difference between a 15 amp receptacle and a 20 amp receptacle, of the same grade, is the plastic face. The guts are the same.


Also,

2007ULWhiteBook said:
Single and duplex receptacles rated 15 and 20 A that are provided with
more than one set of terminals for the connection of line and neutral conductors
have been investigated to feed branch circuit conductors connected
to o.ther outlets on a multi-outlet branch circuit, as follows:

Back wire (screw actuated clamp type) terminations with multiple wire
a.ccess holes used concurrently to terminate more than one conductor

Side wire (binding screw) terminals used concurrently with their
respective push-in (screwless) terminations to terminate more than one
conductor
 
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