AsaSmith wrote:Pursuivant wrote:So what happens if you get an electrical surge with no fuse in France? Everything goes pop?
You get a major case of oh-la-la
No, the thing is the fuses are in a box, next to the electric meter, not all around the place.
Doesnt that beg the question why do we have individual fuses in that case?
UK houses have their power sockets wired in what is called a ring main - a kind of loop starting from the fuse box, travelling from socket to socket and then back to the fuse box. So the load can travel two ways from the socket to the fuse box. This allows a lot of sockets to be served from one fuse in the fuse box and to handle this the fuse in the fuse box is quite big (30A). If each device plugged in didn't have its own fuse, then it could draw 30A before the main fuse cut the power. Considering a TV might draw 1A and even a toaster or hairdryer only 10A, then 30A will see some flames before the power is cut. So that's why UK items have their own fuse.
In europe the ring main isn't used, but instead a star type system, with individual wiring to each socket. So the fuse in the fusebox is much lower (eg 16A). So there is no need for individual fuses although you might think it would be good for those low power things like TV's and DVD players to trip at 3A like in the UK rather than 16A but that doesn't seem to cause much concern in europe (in the same way that swapping the live/neutral doesn't bother the germans/finns)
Fuses aren't all that good for "surges". They are good for over current situations which are normally caused by your kettle, iron, tv etc going wrong. The fuse will save the device or cable catching fire. But a fuse doesn't control the voltage and monitor that.
"surges" like you get from lightning or living next to a factory that suddenly causes a voltage drop are better handled by an RCD circuit breaker (aka ELCB). This will cut the power in this kind of situation (although no guarantee it will do so in time). A fuse would not help you in this situation, 1000v down the line to your tv will get there before the fuse can do anything since there is not a huge amount of current in the surge, it is the voltage that will cause the damage.
Most of my problems (living in the countryside) are surges coming down the phone line and into the ADSL modem and from there into the network socket of the PC. In the worst case (like when I lived in the UK) it will carry on into your home mains wiring and blow up non computer items (most likely those with lots of digital electronics inside rather than things like toasters and kettles).