Burnt electrical outlet and plug

We recently had one burnt electrical outlet at our office. The appliance plug is also burnt as well. All the outlets at our office is rated at 20Amps and have fuse protection. The fuse did not trip. Anyone has a clue why the outlet and the plug are burnt? I am planning to just replace the burnt outlets and the appliance plug, but I really prefer to know what caused the burning in the first place.

Here are 2 photos showing the plug and the outlet:

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Thanks

Reply to
dchou4u
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What types of devices to those plugs belong to? Not the outlets. The plugs.

Reply to
JoeSpareBedroom

It is connected to a power conditioner which powers some audio devices. The input to the power conditioner shows it is rated up to

30Amps but we actually do not have that many devices being powered by this conditioner. So I doubt it is drawing the full 30Amps. Also the 20Amp building fuse would have tripped if the power drain was higher than 20Amps.
Reply to
dchou4u

Without having a beter look , I would say that in the plug where the wire is connected to the prong, there is a loose or high resistance connection.

You usually get heat build up at the bad connections. If the plug can be taken apart, see if the connection is loose. Unless there is some reason the whole prong is not making connection all over the plug and socket, there probably was nothing wrong with the socket except the plug overheated and caused the burnt spots on the socket.

Reply to
Ralph Mowery

If this was a cheap receptacle, that is the expected result. Put in a spec grade receptacle (it will be in a box, not loose in a bin) and it should be OK.

Reply to
gfretwell

Bad (high resistance) connection between the plug & receptacle neutral contacts.

I'm betting that it took a fair amount of time (many months) for the problem to manifest.

Get a better grade of receptacle & plug. Make sure that the plug withdrawal force is good.

The fuse (circuit breaker?) never did its job because the amperage draw was lower than its rating.

cheers Bob

Reply to
DD_BobK

There is something wrong with that plug. Open it up and look inside.

Reply to
Molly Brown

Replace the plug. It has a poor connection that resulted in overheating which was left go until it ruined the outlet... and then ruined the other outlet. The average person thinks they are safe from electrical fires if the fuses/breakers work, and there is no short circuits. The truth is that most electrical fires are due to poor connections... just like you have. It should have been repaired after it burnt up the first outlet. Be sure to replace the outlets also. If you can't replace the plug and the outlets, please call a qualified electrician before you burn down the office.

Reply to
Tony Miklos

Is the "conditioner" the plug is on a Ferro-resonant transformer type AC Voltage regulator? They can be really nasty to a high-resistance connection - a lot worse than a non-resonant load.

Reply to
clare

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This is are arc-fault breakers are supposed to help. I'm with you, though. A better outlet/plug, properly installed, would have avoided this problem completely.

Reply to
krw

Why are two outlets discolored? Is it a fuse or a circuit-breaker, fuses blow, circuit breakers trip, you mixed up words for both devices, which is it?

Reply to
hrhofmann

It looks as if someone plugged it into a different socket, proving that the low resistance (bad connection) is in the plug. When taking apart the plug observe the terminal condition. As mentioned previously the wire to spade connection was probably compromised. Cut off at least 4 inches to find bright copper, install a NEW plug maybe soldering, or crimping on a spade, tighten securely, and plug it into one of the unburnt sockets. Feel the appliance wire for abnormal temperature. Observe any and all safety procedures.

Reply to
den

I see this all the time at my job / business.

Bad plug melts and burns damaging both receptable and plug, high resistance heating.

Replace both plug and receptable check for heated wires at receptable too. cut wire back from plug overheated plug wire will not connect well and lead to futher overheating. coppewr tends to look dark.

Reply to
hallerb

Observe any and all safety procedures. Note which

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missed that completely!
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is current doing on the NEUTRAL wire! Get one of these
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see if house wiring is correct. If O.K there is a ground / neutral disconnect in the device

Reply to
den

My neighbour had a fire in an 4-outlet box(industry quality) 4 days ago. Turned out, one of the screws was not tightened enough, the insulation had burned off 2 inches of wire, and a short developed, where the wire touched the other feed wire, but current was not enough to trip the fuse, because there was no actual metal contact, just carbonized insulation(when hot, that conducts). After checking out the whole box, 6 screws turned out to be tightened rather sloppy. So, it might be prudent to check out wiring and screws in your office.

In our case, the outlets were high quality, but assembly sucked. The outlet in question fell apart when checked out.

Reply to
Sjouke Burry

Going back to the X0 terminal of the transformer? That is how it works.

Reply to
gfretwell

bad connection inside the plug. The outlet is probably ok.

Reply to
Steve Barker

Best way to sell a house now days. When you get an arc going all bets are off as to how much heat is generated and woe to you if the wall has flammable covering or a curtain is against it. Ever do any arc welding? From the looks of the photos though this one looks like it might have been to much current going through a bad internal connection for to long of time. And probably someone didn't get a good connection when they attached the plug to the wire or pinched the wire to much or not enough when attaching the plug. What device or devices is this thing running? It must require lot of current. Things like this are not supposed to happen.

Reply to
Fat Dumb & Happy

Thats sounds like a good explanation to me. I would also question the draw of the appliance. It burned two receptacles and it's not a factory plug. There is a good possibility that it should be a 20 amp plug and not 15 as shown

Reply to
RBM

Good possibility? It is a definite FACT. With the 30 amp rating of the conditioner,a 20 amp plug would be a requirement. Particularly on a 20 amp circuit.

And I'm still asking if this is a ferro-resonant regulator device.

Reply to
clare

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