XPost: uk.tech.broadcast, uk.tech.digital-tv, uk.rec.audio   
   XPost: sci.electronics.repair   
   From: mapson.scarts@btinternet.INVALID   
      
   "Dave Plowman (News)"  wrote in message   
   news:525ac9f71adave@davenoise.co.uk...   
   : In article ,   
   :   Ron  wrote:   
   : > > You may have noticed that flex sizes have become more   
   uniform recently   
   : > > - all are now capable of blowing a 13 amps fuse in the plug   
   regardless   
   : > > in event of a short. As it seems using the correct fuse in   
   a plug is   
   : > > beyond most.   
   : > >   
   : >   I suspect that's because the average person goes into a   
   shop and buys   
   : > a mains plug for his (say) desk lamp. He gets it home to find   
   it's   
   : > fitted with  13 amp fuse, either through not knowing any   
   better or just   
   : > not having any 1 amp, 2 amp or 5amp fuses in the house, fits   
   the plug   
   : > anyway.   
   :   
   : Surely everything by law is now supplied with a plug fitted?   
      
   Whooossshhhhh.... Whilst there is a problem with incorrectly   
   wired plugs there is a bigger problem of plugs fitted with the   
   incorrectly rated fuse.   
      
   :   
   : > It's still not really a problem because the lamps mains cable   
   is almost   
   : > certainly heavy enough to blow a 13 amp fuse if there's a   
   dead short.   
   : > It's pretty academic anyway as these days all domestic   
   appliances in the   
   : > UK are supposed to be supplied with a fitted plugtop with the   
   : > (hopefully)correct fuse.   
   :   
   : Yup. Some seem to think the flex rating is that where it could   
   only just   
   : blow a fuse of that rating.   
   :   
   : Jerry's favourite - 3 amp flex - has a cross sectional area of   
   0.5mm^.   
   : Fusewire of the same cross section is rated at 30 amps...   
      
   So a flex fitted to a plug that has had its fuse bridged out will   
   likely start to melt if feed from a ring circuit should the   
   appliance become faulty (short circuit), is that what you have   
   finally grasped Plowman, BINGO! Also don't assume that all   
   properties are protected by RCD's etc, many are still protected   
   by slooooooow acting fuse wire.   
      
   The risk is, this 3 amp flex *you* keep talking about will behave   
   exactly like a fusible link-wire as it *will* be the weakest   
   link, now should that flex be trailing across the carpet or some   
   other flammable item, such as curtains or the odd magazine left   
   on the floor next to the reading lamp.... OTOH if fed from a   
   radial circuit protected at 15 amps (or better and more likely,   
   via 5 amp socket off the lighting circuit) it will be the breaker   
   at the panel and not the flex that will be the weak link.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)