18v at fluorescent

[Mega Greg]

Hi all,

I went out to a weekend call out where the customer had had a fluorecent tube and starter replaced. Apparently the light had shone brightly for a short time and then went out.

I opened up an outer piece of casing which revealed little more than a choc block. I tested for voltage and got constant readings of 18V LN and 10V LE (0V NE). There was no apparent means of openning up the lamp and not wanting to risk breaking an old fitting in the evening I am yet to look inside. fixed wiring (black insulated) seems to just reach the choc block from beneath the fitting with the white insulated wiring for the fitting on the other side.

Is there something basic I am missing here?

 

[Lucien Nunes]

If it has a starter there must be a choke somewhere. With the tube out you should read mains voltage between one pin at one end and one at the other, and nothing on the other two that connect to the starter. Sounds like a duff choke, shorted turns will overrun the lamp.

 

[amlu]

18 volts l-n on the chockblock with incoming power? theres your problem, have a look whats up on the rest of the circuit.
if thats black insulation and its old you may have a VIR cable and its insulation may fall apart as soon as you disturb it.

 

[Mega Greg]

18 volts l-n on the chockblock with incoming power? theres your problem, have a look whats up on the rest of the circuit.
if thats black insulation and its old you may have a VIR cable and its insulation may fall apart as soon as you disturb it.

Thanks both

the light is on the down light circuit which is happily populated by 240 fittings. The replaced starter and starter fitting is of standard type and the tube fitting has standard pins.

the black insulation of the conductors seems to be PVC, nothing crumbly about it.

the physical sequence of the components are:

main body of fitting
black insulated conductors
choc block giving 18v LN and 10v LE and positioned ~3 mm from main fitting
white insulated conductors looping back into the fitting

any further thoughts

 

[guest119]

Tell them to call an electrician in to sort it.

Boydy