PCFormat Forum Archive

Hi everyone,

Last night my wall plug started making weird crackling sounds.

S look under my table and see nothing. then my pc randomly restarted.

Started to panic as i thought my pc hard drive is ganna bomb out. so i just had to kill the power by the PSU switch.

thats when i noticed the cracklingwas a lot louder without pc noise...

so crawled under table and switched off the power switch crackling stops.

decided to pull out plug and burnt my fingers trying to pull on the plug. so i pull the desk away feel the plug is hot.

so i go get a pair of pliers and use that to pull out. the dam plug was melted inside the socket.

here is the extension lead with burt extra crispy LIVE pin. As you can tell its short way from bursting into flames.



In the second pic you can see what i am running off this very short extension cable. its a 5-way multi-plug.


FROM the left: 23" LCD monitor, computer box, 17" CRT, Adsl modem, extension lead running to my bed for phone to charge at night

Now my question is: Is his enough power draw to roast my power socket?

i am running 350 WATT PSU BTW

Had this happened to you?

What do you run in your room?

do you leave it on 24/7/365?

my pc is only on when i use it.

My dad is moaning at me that its because i have all this stuff running?

is this really that much.

want to hear your input on this.

any electricians on PCF?

I would say far too little, but the power would have tripped on the plug well before burning crispy.But my guess is the wall socket has a loose connection.

Most plugs use a 16amp trip switch with two to four plugs on a switch depending on the house configuration.Multiply volts times amps to get watts: 16 x 220 = 3520 watts.Even then it would have tripped well before burning.

You are assuming his multi plug has a trip built in

But I concur. That load should not cause crispy plugs. You probably have a short.

Yeah, either a short or the contact within the wall socket does not make proper contact with the plug. I suspect the latter.

What about the plug on the extension, I have seen one or two burn like that and simply replaced the extension with a better rated one. Check what the Amp rating is on that one, it looks a light duty cable maybe 1.5mm cores inside or less. Is it SABS approved?

It's also important to note that the circuit breaker should be the weakest part of the connection. I stand to be corrected by a certified electrician but I am quite sure that if your cable is for example 20A max and your circuit breaker rated 80A, it's not gonna trip when the plug starts melting.

Correct. (not that I'm an electrician) But that is spot on.

It's also important to note that the circuit breaker should be the weakest part of the connection. I stand to be corrected by a certified electrician but I am quite sure that if your cable is for example 20A max and your circuit breaker rated 80A, it's not gonna trip when the plug starts melting.

One of the main reason you have a earth leakage breaker, any overload, under load it has a 30ma tolerance so if it doesn't trip you DB board doesn't have one which by law it must or not wired correctly or it is faulty.

Well i have done a check on the lead... its a 10AMP lead 250V with MAX watt of 2200.

seems like the lead is not as heavy duty as i thought it was. the cable is nice and thick but i guess the cores must be thin for only 10A?

I am now running all my stuff off a lead from another plug.

how this one is higher rated...

Looks like it was nearly a deathstrike...Yeeeeaaaahhhh!

BAd humour aside:

First and foremost, most extension cords are only rated ten amps. The cheap ones may be as little as five.
Secondly, always uncoil your extension cord fully when in use. The coils act like an inductor if you don't
Third, as a rule of thumb, a the rated current should be divided by the number of connections on a multiplug. You cannot draw 16 Amps off of each socket. In fact you'll soon cook it if you draw 16 amps off of a single socket.

Your earth leakage performs 2 functions. It should have a leakage detection circuit which measures a difference between the current in the live and nuetral lines. If it's "leaking" to earth, then the current flowing down live is greater than the current returning on the neutral and it will trip. the 20ma tolerance is a safety factor. 60ma across your heart will kill you. -->20ma is a 3x safety factor. It should also have an overload circuit. But overload is normally 60 Amps so if your plug is cooking, it won't necessarily trip it. This is where you have subcircuits with lighter breakers. 20A is typical on a breaker. if its too low, it will trip when you run more than one or 2 largish appliances on it.