GFI outlet issues

[ttabbal]

We can't use 14 gauge wire on 15 amp circuits, everything is minimum of 12 gauge.

That's one I support. 14 gauge is too small in my opinion. This happened in my house, partly as a result of smaller wire. Load never tripped the 15A breaker. Measurements never got above 12A. The damaged plug was not in use, the heat came from the back as far as I can tell. I replaced the breaker as well to be on the safe side. A little extra copper costs less than a fire.

Looking at this again makes me want to swap all the 14 gauge circuits to 10A breakers, if I can find some..

 

[tq60]

That was NOT the wire size, if it was it would have been melted inside the wall.

That was poor connection at the outlet.

Simple ohm's law...

The heat (watts) is greater where resistance is greater.

E=i*r, p=i*e, p is watts, series circuit has i (amps) equal in all parts, voltage is different in all parts related to resistance.

A poor connection has resistance, current flow across that resistance generates the heat.

Looks like the return side of outlet was not a tight fit on heavy load and that started the chain of events that created the heat that resulted in metals relaxing reducungcontact and generating more heat.

Cheap outlet with heavy load.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[ttabbal]

I wondered about the resistance of the connection. It was wired with the spring terminals in the back. I have never really liked those. The replacement is done with the screw terminals and feels much more solid.

 

[Logan Novice]

So far this sounds like it's going to be an increasingly big problem. Great!

I agree, Mike. This isn't something that should be ignored. At some point it will peak and the outcome(s) could be costly. I'm not referring to how it could affect sales, although that is a consideration, but if a user experiences a loss related to a ground fault and the insurance carrier refuses to pay the anguish could be enormous. Let's hope that the manufacturer can get back with his electronics engineering group and figure out how to fix this.

 

[Logan Novice]

$5 30A breaker and 5 minutes was pretty simple for me. My state only requires GFI in kitchens and bathrooms, washing machines and water heaters get a pass.

But for the 30A breaker the wire size requirement is #10. If the user stays with 12 gauge wire on 30 amps the wire will fail before he breaker trips; that's a fire hazard.

 

[KevinM]

But for the 30A breaker the wire size requirement is #10. If the user stays with 12 gauge wire on 30 amps the wire will fail before he breaker trips; that's a fire hazard.

The circuit uses 12 gauge with a 1' wire length which is adequate.

 

[Logan Novice]

The circuit uses 12 gauge with a 1' wire length which is adequate.

Thanks ... I appreciate knowing that.
Let's not lose sight of the original problem under discussion though. GFI nuisance tripping isn't going to be eliminated by a breaker with higher amperage rating.

 

[KevinM]

Thanks ... I appreciate knowing that.
Let's not lose sight of the original problem under discussion though. GFI nuisance tripping isn't going to be eliminated by a breaker with higher amperage rating.

It is a transient spike that trips the breaker, not an extended current consumption.

 

[middle.road]

I've got a 36' enclosed car hauler about 50' from the shop. (Which is now an awful mess of a storage shed.)
I ran a 'temporary' 12ga cord to it with a site grade GFI plug at the shop end. (Need to figure out how to run conduit under 24'+ of concrete.)
The trailer is properly wired for AC, with a breaker subpanel and all.
It has two 4' florescent tube fixtures, plus I run the tumblers out there and I have an electric power washer out by the trailer and occasionally I'll run the small compressor to fill up tires.
Only issue is that the pressure washer will sometimes go into a "growling trying to engage" mode when sitting idle, and that trips the 15a breaker way back on the garage subpanel and not the GFI plug at the outlet.
Then I've got another 12ga extension cord made up with another GFI plug for use outside of the shop on the driveway or yard. Never has tripped with weed trimmers or drills or the electric chainsaw.

 

[RJSakowski]

I wondered about the resistance of the connection. It was wired with the spring terminals in the back. I have never really liked those. The replacement is done with the screw terminals and feels much more solid.

I never use the spring terminals for electrical connections. It's just asking for trouble. They are OK as long as there is no corrosion but if any corrosion develops the resistance will increase resulting in more corrosion and higher resistance. Things should be designed for worst case scenarios, not best case. Considering the scorch marks on the neutral on the front, I would suspect a high resistance plug connection may have started the

I only use 14 AWG wire for lighting where I know that the current draw will be on the order of a few amps at most. Never on outlets.

Regarding using a 30 amp breaker with 12 AWG wire, 12AWG copper has a resistance of 1.6 milliohms/ft. If it were carrying 30 amps, the wire would experience a power dissipation of 1.4 watt/ft per conductor. By comparison, a heat tape used to keep pipes from freezing has a power dissipation of 7 watt/ft. I would not expect a catastrophic wire failure due to a 30 amp draw.

However, the point about insurance not covering a loss if the breaker was mismatched with the wire size and a fire was even remotely connected is well made.