Not a good start to the day!

[macmini]

So, there i am, eating my cereals, enjoying them too, i might add .

I thought i could smell burning, looked at the heater to see if i'd left my chair near it, but, no, all clear, strange.

Left it a few minutes and the smell were getting stronger, i looked behind my chair and saw this....

Nothing were connected at the time, all it usually has connected is my convector heater, in the opposite socket to the 'bad' one.

Anyway, i'm guessing that over the years, the load of the convector heater has loosened the neutral connector? does this seem feasible?

http://i48.photobucket.com/albums/f223/macminiforum/DSC00245.jpg

and....

http://i48.photobucket.com/albums/f223/macminiforum/DSC00247.jpg

 

[PompeySparks]

A heater takes quite a high load through a socket. If you have been repeatedly using the same socket then the drawing of this current heats up the copper which then cools and contracts once the heater if turned off. This repeated expansion/contraction can work conductors loose!

 

[macmini]

A heater takes quite a high load through a socket. If you have been repeatedly using the same socket then the drawing of this current heats up the copper which then cools and contracts once the heater if turned off. This repeated expansion/contraction can work conductors loose!

As i suspected.

 

[Pensdown]

A heater takes quite a high load through a socket. If you have been repeatedly using the same socket then the drawing of this current heats up the copper which then cools and contracts once the heater if turned off. This repeated expansion/contraction can work conductors loose!

If that was true, then the terminals on the MCB should also have burnt out as they also carried the load. That picture is the best example I've seen of a DIY job (wickes socket) gone wrong. The terminal was either loose (weak wrist) or it was miss terminated, ie missed the copper got the insulation.

 

[PompeySparks]

I see your point but they may not have both worked loose at the same time - the pins of the socket add extra resistance (they may have been dirty) which would have added more heat at the socket end - the MCB also has a more rhobust terminal connection...

Then again, like you say, it may have just been a poor connection in the first place!

 

[macmini]

The connections were perfect when the socket were installed (at least nine years ago!).

Oh well, you win some you lose some.

 

[TeesdaleSpark]

The problem could be a loose connection in your plug.

 

[macmini]

that's actually a good point, but, if that were the case, wouldn't the plug have burnt and not the socket?

 

[Pensdown]

The connections were perfect when the socket were installed (at least nine years ago!).

Oh well, you win some you lose some.

Just a tip, spend a few coppers more on the socket when you change it. MK, Crabtree, they all have much better terminals.

 

[macmini]

I intended to, believe me, but, with the cable being so badly burnt, i had no choice but to get another one of the Wickes sockets, reason being, the spacing of the terminals is unique, and i only had enough slack cable to do that!

 

[tim-spam]

It probably all comes down to the materials used. Copper and brass have very similar coefficients of thermal expansion, so this thermal cycling causing a terminal to work loose should not happen. However, if a different material was used with a different coefficient of thermal expansion, this may happen. Do the cheaper sockets use different materials? Certainly the Wickes sockets I have seen don't look too bad.

 

[ban-all-sheds]

I thought i could smell burning, looked at the heater to see if i'd left my chair near it, but, no, all clear, strange.

Left it a few minutes and the smell were getting stronger, i looked behind my chair and saw this....

That's appalling.

I find it hard to believe that that amount of burning, or those bloody great cracks could have happened in just a few minutes

 

[Pensdown]

The problem could be a loose connection in your plug.

The burning is isolated to the terminal so I don't think in this case it was the plug.

That's appalling.

I find it hard to believe that that amount of burning, or those bloody great cracks could have happened in just a few minutes

When the connection finally gives up they do get very hot very quickly. We use the infra red heat scanners http://www.testequipmentdepot.com/fluke/thermometers/infrared.htm on switchgear that cant be turned off and it's quite surprising how much heat is generated at the terminal once the copper starts to anneal. The copper gets soft though the hot-cold cycle and then it flows away from the screw terminal. (like the old ali cables used to do) This is why they become loose and how every hard you try you can never re-tighten them. As soon as the screw becomes tight on the cable the copper flows away from the connection and its loose again.

Now that I've bored you all to tears, I better get on with some work