Streetlights, what will the answer be?

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..... :confused:
 
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street lamps? actual council owned ones or ones on the school grounds?

if the former then there is NO fuse on the supply usually.. or a very large one if there is..

my cousin dug one up once ( drives diggers for the council ) and tried to short it out so the guys could carry on working in the trench..
many sparks and melted bits of bucket later and it was still live..
 
Why switch the lights with a switch? Seems an odd arangement.

What about other protective devices - RCDs etc. Perhaps a fuse or MCB elsewhere has tripped. Are the whole lot also fused in the first column?
 
All privately owned, there is a Henley cut out with a 2A fuse in each column, the fuse only controls the head of that column. Was all installed new in 1966 but heads were changed by me last year for these nasty CFL ones (their choice!!). Switched! not my idea, switch is say 10 years old, MCB also runs two florrys in boiler room that were still on... :confused:
 
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Its been an odd day today, had a call from a county architect about the power supply required to a 20' X 20' temporary building, his drawing of the foundation and wall took me by surprise when I read 100A 3Phase supply - I assumed a mistake, conversation went sort of..

me 100A :eek: 3ph :eek: really, in a kabin, whats going in it?

tect lights, sockets (single ph) 2X storage heaters.

me 100A, 3ph, why, do you realise how much 200mtrs of cable for this will cost!!!

tect Have you got a problem with it?, can't you do it?, do you want my work?

me Its your money, hang up phone
:eek: :eek:
 
Too cold for your cfl's to fire? Incorrectly chosen lamp.

That is very likely. two of my outdoor CFLs will not fire up in this cold weather.

Flourescent lighing for refrigerated transport ( below minus 10 C ) often has an incandescent lamp for instant light and to heat the CFL ( on 24 v inverter ) until it is warm enough to ensure the tube can strike.
 
It's where I place my money. Site festoon lights are usually cfl's these days too, and they struggle.
 
Well i'll let you know what the problem is tomorrow, thanks for the ideas
 
my cousin dug one up once ( drives diggers for the council ) and tried to short it out so the guys could carry on working in the trench..
many sparks and melted bits of bucket later and it was still live..

__________________
If you make everything idiot proof, evolution will just make a better idiot.

.

Looks like your cousins side of the family is on the avant garde of the evolution you allude too.
 
Right, the solution

When I got there today I could see more clearly in the daylight and notices that along from the trunking into which the rotary switch is wired there was a very rusty MK grid 3X 3gang switch, don't know why but something told me this could hold the answer, it had 8 dirty switches and one key switch on it, I removed the cover and only the keyswitch was wired up with 4 neutrals in one side and 4 in the other, the switch had been turned off during an emergency light test and not switched on again - cutting off the neutral to the lights. Why it was done like this i'll never know, but its a bloomin mess so after the hols i'm going to re-wire the lot with dusk to dawn control for the lights - that switch is now removed!!
 
I was recently working in a church and all the organ contactor control wiring was switched neutral.

I'll have to post some pics when I have a bit of time.
 
A switched neutral. Don't see that often...not without the line being switched at the same time ;)

Reminds me of many (!) years ago when I lived with my parents and my bedroom supply failed. I checked the socket with a neon screwdriver and found that it was live so deduced that the fuse was OK and the neutral cable must have broken. ;) It was later found that the (council) house had fused neutrals. :eek: Meatime I 'fixed' the problem by shorting neutral to earth in the plugtop. :eek: Dear oh dear but I was only 12.
 

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