Problem with T8 fluorescent tube and SRS ballast ?

[john77]

I've got an old twin striplight fitting in a garage which wasn't working. I replaced the blown 1.25 amp fuse inside the fixture with a 3 amp one and now one of the 5 foot T12 tubes is working. I tried swapping them round to check it was the tube and not the circuit.

I read somewhere that you can't use the T8 replacement tubes if there is a Thorn SRS ballast in the fitting - which there is. Does anyone know why this is and if there is any other solution ? T12 tubes still appear to be available but only if you buy at least 4, which would make it cheaper to replace the fixture.

Thanks

John

 

[riveralt]

I've got an old twin striplight fitting in a garage which wasn't working..........which would make it cheaper to replace the fixture.

You seem to have answered you own question

 

[john77]

Yes, you may well be right - but I'm curious to know the reason why a T8 tube won't work with an SRS ballast.

 

[riveralt]

Yes, you may well be right - but I'm curious to know the reason why a T8 tube won't work with an SRS ballast.

A search on wiki will give you the details but, in summary, they say it is to do with the fact that T8 have a higher starting voltage than T12 and may not start reliably especially in cold weather.

 

[333rocky333]

Not sure what a srs ballast is, but if its a starterless one then as riveralt says it fails to strike the lamp [ dont know why] once it strikes which it sometimes does it runs ok but a majority of times it wont strike.
If its old but has a starter then it Will 99% of the time run a T8 lamp fine.

Not sure from what you say is it the lamp fault or the control.
If its an old starter fitting, most old twins had a capacitor in series with one lamp for anti strobing, this commonly fails due to age and removal can reinstate the second lamp.
Though if strobing can be hazourdous this is NOT advisable although new twins dont have the feature anyway