Overcurrent in circuits

[dtec dave]

Evening all...just a quick question. A customer was using a wallpaper stripper on a ring circuit, smoke started coming out of the back of the socket before the 32amp breaker tripped, what I don't understand is why the 13amp fuse in the plug didn't break? Could someone tell me why? Thanks

 

[Knobhead]

Sawn off 6" nails tend to hold longer than the MCB.

Sockets seem to get a bit upset with gross overloads.

 

[plugsandsparks]

Pffttt thats nothing!
We had a fire alarm go off caused by 2x 3kw heaters plugged into a 25m rolled up lead.

It was a pile of PVC mush and coper when i got to it LOL

Yep ditto, i felt compelled to break open the reel to have a look see, i was impressed with the damage. The inner turns were all stuck together in a melted mass.

 

[Guest111]

I remember a few years back and one of the in ln laws wanted to borrow my welder,I asked him if he wanted the extension lead as well,because I had a nice heavy one for the welder.No he already had a nice new lead,anyway he brought the welder back later very annoyed as it had "broken" his new lead! He had bought one of those 50 foot roll ones from one of the sheds,pulled off about 20' and started to weld,his welding on the metal wasn't that good but he'd made a lovely job of "welding"the cable to the reel.obviously he didn't see the bit about unwind fully before use.

 

[gazj82]

Also don't forget a fault will usually take the weakest part of the circuit out. i.e if your ring main is already running at 25A with 7A to spare. 7<13 so you will probably take the MCB first. Well so I have always been led to belive.