Fluorescent lights not working. What could have caused this?

[andr]

Hi,
I was carrying out an upgrade of a 3 phase distribution board today.
Everything seemed to go ok apart from no neutrals corresponding with their live conductors.
But when I have re-energised the circuits there is a group of fluorescent lights not working.
Thay are just glowing at either end.
I have correct voltage accross live & neutral. What has damaged these lights?

Also at the mains there was a large main switch labelled capacitor. I have not come accross one at a mains before. what is its purpose? The site was a fabricating workshop.


Thanks for any help.

 

[IQ Electrical]

The capacitor is probably for power factor correction.

Are the failed fittings in random locations or consecutive?

 

[davelerave]

the capacitor is for PFC

glowing at ends can mean starter-but prob not here

maybe they're cold or a fault

 

[andr]

The failed fittings are in the same location, accross 2 rooms. There are lights on this circuit working fine. 2 of the fittings are only about three months old.

 

[Hawk81]

Have you tried new tubes and starters?

 

[andr]

No didnt have time today and it was an unexpected fault. I'll probably just replace them on monday. Was just confused as to why its happened when before the change-over they were ok

 

[Mr Mark Sparks]

did you at anytime energise the board with the main neutral disconnected
this is a long shot but it can cause problems

 

[davelerave]

how many lights

are they magnetic or electronic ballast

 

[davelerave]

ya-that could have maybe happened-overvoltage

 

[andr]

I could well have done that because I was having problems with finding the correct neutrals. Many redundant phase cables were disconnected but I still had lots of neutrals.

 

[andr]

Only 4 lights out of about 90.

 

[davelerave]

maybe there was an overvoltage situation -have to be very careful with neutrals on 3-phase

are they high-frequency


ahh 4 out of 90-maybe its nothing try tube and starter

any other issues after

 

[Mr Mark Sparks]

its easy done we fried a ups and an intruder alarm a few weeks ago
it doesnt all ways happen but it can
our client understood and didnt make us pay

 

[ian]

I assume you are checking the voltage at the fitting terminals, try disconnecting the switch wire and neutral at the light and see what you get there. Its possible to pick up an earth reading though the ballast which would show on the neutral.

Ian

 

[andr]

ok i'll accept the over-voltage explanation.
The most confusing thing was that this light circuit was not even fed from this board. The circuit was fed from a db that stayed live.

However, the neutral may have come from the board that I was working on.
Its an old insatallation and a bit of a cock up.

 

[DurhamSparky]

chances are the light started has failed and when you pulled power off they wont be able to start up again! as above replace started and tubes!! probably nothing!