dimming fluorescent tube

[knasher]

Hi All,
A friend has just mentioned that when they turn their living room light off (a class 1 fitting with 3x 60w lamps controlled by a 1 gang, 1 way switch switch) the flourescent light in the kitchen goes off for about 5 seconds too then comes back on. Its controlled by a 1 gang, 1way switch.Any ideas what might cause this? Could it be the ballast in the kitchen light? Some sort of induction issue? Can't say I've got a clue really!
Be interersting to hear any of you ideas please.

 

[Marvo]

Could be a drop in voltage at the fluorescent when the other light is switched on. You should be able to see this with a decent tester. Check for poor connections or terminations which might typically cause this sort of problem.

 

[ringer]

OP said kitchen fluorescent goes off for 5 secs when lounge lights are turned OFF

Ballast acts like a capacitor - seems that it is discharging somehow - back into the lounge bulbs via neutral? Only guessing here mind.
Have you checked - are both sets of lights switched on the live? Is one or both of them switched on the neutral?

 

[knasher]

Thanks for that - can VD be measured by clamp meter on R1 to get current, then measure Zs at the board and deduct Ze from this to get R1 +R2 resistance. I was then going to use V = I X R to get VD. Does that make sense?

 

[knasher]

hi ringer, havent been to go look at this problem yet but will open switches up etc to see if I can spot anything obvious.

 

[telectrix]

in a word, no. visual check of both fittings and their switches. should locate problem. if not, measure voltages and see what happens when lights are switched on and off

 

[knasher]

cheers lads, will bear all this in mind when I go and take a look

 

[Marvo]

OP said kitchen fluorescent goes off for 5 secs when lounge lights are turned OFF

Oops..... misread.