120 volt GFI burned up

[Uncle Gump]

So yesterday I was making chili and it sounded like someone started up a sickly skil saw in my basement. Made the dog bark and bolt outside to fend off the intruder... and I followed. Walking back in the house I could smell burnt electrical. I went to the basement and the GFI my washer and dryer were plugged in was cooked.

So this circuit also has the two kitchen GFI's on it... and there was no electrical load on any plug when this thing smoked. Seems strange to me... and I'm not sure what the root cause of it is. The ground wire was burnt right in two... loose connection and degraded the GFI slowly until it had enough? I know many of you are experts in this area... help me with your thoughts and a direction to head. I don't want to set the house on fire in another failure.

 

[ThatOneGuy]

I was an apprentice electrician for a couple years so I know a little. That looks like it was a short internally in the outlet. It's unlikely it was caused by something in the wireing. I would however be worried about heat damage to the wires. Would suggest if damage appears to go further than the box, you may need to open the wall, and replace any suspect wire section. It would also be wise to hire an electrician to come diagnose the issue as a safety measure, even if you feel comfortable making the repairs yourself.

 

[superj]

my travel trailer had its gfi in the bathroom suddenly give out. the rv place said they just do that randomly and just put another one in.

mine was not melted like yours though. i would be worried and dig through the insulation a bit to see how far there is black wires and how much needed to be replaced now

 

[RonD]

GFI outlet protects the devices plugged into the outlet, it will cut power to the outlets only

So no protection for the wiring behind the GFI outlet

GFI Breaker in the panel will protect wiring behind the outlets and the outlets themselves, so the whole circuit

You can run both, a GFI breaker and then a GFI outlet on each plug on that circuit, electrical code usually requires only one or the other, but its your house, so you can used both

I assume the breaker in the panel shut off, if not then that would be a, or the, problem, bad breaker


I have GFI breakers on garage outlets and outside outlets
Then GFI breaker on 3 bathroom outlets, one circuit, each outlet is also GFI model, but thats because wife and daughter would blow the GFI breaker with hair dryers, blow driers, all the time, lol, well often maybe not all the time
Now they just blow the outlet breaker and can reset it themselves

 

[Curious Hound]

GFCI devices seem to fail often without provocation. I understand their safety purpose and how they work. But I don't like them. Never saw one fail like that in all my years as an electrician. If there truly was no load anywhere on the circuit, then it just failed due to old age and bad quality. But even that should not happen without current flowing (load) in the circuit.

As mentioned above, any and all wiring at that area with discolored insulation or other signs of heat needs to be replaced. Then install a new device and everything should be fine.

Just as a reminder; GFCI devices do NOT protect against an overloaded circuit. Only the circuit breaker or fuse does that. The GFCI device (breaker or receptacle style) is only there to protect you from getting shocked. It does this by sensing a mismatch between the current on the hot wire and the current on the neutral wire. A mismatch of just a few milliamps "assumes" that the remaining amps are flowing through you to ground and therefore turns off power to the load and your body.

BtW, glad you're safe.

 

[Uncle Gump]

Ok... so this GFI is connected to a 30amp circuit breaker in the panel. It did trip the breaker during the meltdown. The circuit was run with Romex and I cut the covering back a bit and the individual wire insulation isn't even discolored. So I believe the wiring is OK.

I went and bought a new GFI outlet and I noticed they had both 15 amp and a 20 amp. I bought the 20 amp. It seems like to get a 30 amp GFI it has to be in the form of a GFI breaker.

I couldn't really see the entire part number on the burnt one but what I could see of it was different then the 20 amp I bought. They are both Leviton brand. So maybe they had a 15 amp GFI outlet for use on the washer dryer? I know when I installed the microwave range hood it said it had to be a 20 amp circuit. I would think a washer/dryer outlet should be at least that. There is some electrical in the basement that was surely done by the homeowner... it doesn't look professional and looks far worse then what I would do... so maybe they bought a 15 amp GFI to save a couple dollars?

I don't know... I'm grasping for a reason this thing burnt up like it did. But I'm about to go put it back together and see what happens.

 

[Curious Hound]

That device definitely should never be on a 30 amp circuit.

Your washer is normally on a 120volt 20amp circuit. Most electric clothes dryers need a 220volt 30amp circuit. These 2 things can not be sharing a circuit. A gas clothes dryer would need a circuit for it's motor and controls. I could see that being a 120volt 20amp circuit. The 220volt 30 amp plug for the dryer will not physically fit in a 120volt 20amp receptacle. The different shapes, sizes and configurations of receptacles is designed to keep you from plugging things into the wrong circuits.

You are right. The microwave is supposed to be on a 120volt 20amp circuit.

It definitely sounds like someone previously did some shady stuff in that house.

 

[Uncle Gump]

Yes they did...

I just turned it back on... and my bad... it is a 20 amp breaker, At least now the GFI rating is the same as the breaker.

Dryer started right up and I through a load of laundry in the washer and it is down there running as I type.

I guess we will see...

EDIT... it is a gas dryer. So 120 is just for the motor and not a heating element.

 

[RonD]

The outlet amp rating(and breaker rating) needs to be below the wire gauge's amp rating
So check what gauge the wire is to confirm it can use 20amps(breaker rating) at that distance from the panel

Home owners often add outlets to a circuit with a 15amp breaker, then breaker will start to trip when all outlets are being used, so they change it to a 20amp breaker...................and that can cause issues

Like in a vehicle, if you install a 30amp fuse on a wire rated for 15 amps, then THE WIRE becomes the fuse, it will heat up and melt before the fuse does
The point of a fuse or breaker is to prevent the wire from becoming the fuse

AMPs go up as Voltage goes down, thats why most of the world uses 230vAC instead of 115vAC, higher voltage means less amps on the wire so its less expensive to wire a house with the smaller gauge wires

In a vehicle the wire gauge is larger because its 12volts so lower voltage, which means higher amps on each wire so bigger gauge is needed

 

[Uncle Gump]

So... if you run a 15 amp GFI at the ragged end it's entire life... seems like it's possible the outlet could get hot and create my thermal event?

Or am I still grasping for the reason.

I believe the Romex is 3 12... Is that a thing? 3 wire 12 gauge.

 

[Curious Hound]

So... if you run a 15 amp GFI at the ragged end it's entire life... seems like it's possible the outlet could get hot and create my thermal event?

Or am I still grasping for the reason.

I believe the Romex is 3 12... Is that a thing? 3 wire 12 gauge.

Don't worry about grasping. Like I said, that's an unusual way for it to fail. But those things fail too often. Normally, they just stop working and you can't reset them any more. There is some fragile electronics magic inside there that just doesn't live long.

12/3 romex would have a black wire, a red wire, a white wire and a bare ground wire.

12/2 romex has all the above except the red wire. They only count the wires that are supposed to carry current when they designate what cable it is. Ground should only carry current during a fault event.

 

[RonD]

An outlets amp rating is for its contacts inside, its internal wiring/plates surface area

In a laundry room humidity can get high, especially if Dryer has/had a leaky Vent Hose
And over time there may have been some corrosion started inside the outlet and it shorted inside

 

[Uncle Gump]

Ok.. it's 12/2.

The basement is damp enough I run a dehumidifier so there is that.

The wiring looks serviceable... the breaker reset... I even pulled the cover off the junction box for the other two outlets and all was snug and no signs of damage. I have a new 20 amp GFI and completed the load of laundry... I'm calling it fixed.

 

[lil_Blue_Ford]

Unfortunately I’ve seen an increase in melted/faulted GFI/GFCI plugs in recent years. Of course most are made in China so… there’s that.

14 gauge wire or anything without modern insulation (plastic Romex or MC/clad) should never be more than 15 amps. 12 gauge is 20 amp. You can use 20 amp outlets on a 15 amp circuit and although it’s not really legal, you can use 15 amp outlets on 20 amp circuits as long as you don’t exceed 15 amp draw on the outlet. So it’s safer to use a higher rating. Big appliances (refrigerator/freezer, microwave, washer/dryer, etc) should always have their own circuits. Arguably you should have the circuits balanced inside the breaker panel by calculating loads but nobody really seems to worry about that anymore

 

[4.0blue98]

Interesting stuff. Sorry, I'm no electrician so can't help with that stuff, but I do have a very important question:

How was the chili?