T
tonyelectric
Heres a festive poser
Was leaving a school site today after a busy day of minor works repairs etc, thinking thats it till the new year - but as I left the caretaker acosted me - the streetlights, switched by a rotary switch had not come on.
A little investigating shows that a drainage contractor dug and back filled a trench across the path of the 2.5 SWA cable half way down the run of 12 lights, wired in parallel with a henley cut out on each - I said OK i'll look tomorrow, its dark now, padlocked the isolator and went home, but then I started to ponder it, the MCB had not tripped, there are 12 lamps in parallel if the cable is cut between 6&7 1 to 6 should come on or if the cut is a short the MCB should trip (its a 6A, the lamps are pewney CFLs), no sensors or timeswitches in the mix.
Well i'll find out in 12 hours or so what the cause is but I thought i'd open it up to the assembled for any flashes of inspiration you may have.
Of course it may have nothing to do with the digging, the isolator could be u/s.....
Was leaving a school site today after a busy day of minor works repairs etc, thinking thats it till the new year - but as I left the caretaker acosted me - the streetlights, switched by a rotary switch had not come on.
A little investigating shows that a drainage contractor dug and back filled a trench across the path of the 2.5 SWA cable half way down the run of 12 lights, wired in parallel with a henley cut out on each - I said OK i'll look tomorrow, its dark now, padlocked the isolator and went home, but then I started to ponder it, the MCB had not tripped, there are 12 lamps in parallel if the cable is cut between 6&7 1 to 6 should come on or if the cut is a short the MCB should trip (its a 6A, the lamps are pewney CFLs), no sensors or timeswitches in the mix.
Well i'll find out in 12 hours or so what the cause is but I thought i'd open it up to the assembled for any flashes of inspiration you may have.
Of course it may have nothing to do with the digging, the isolator could be u/s.....