Choosing the correct ballast?

Richard Burns · May 11, 2018

Simon Burton said:
Well I did look into this and the 4ft lamps are around 1215mm in length, wouldn't this be to big for the 1200mm x 600mm module? Well the guy has changed the lamps he said and the starters and still doesn't work. Can only assume it's will be the ballast, there are 2 ballasts as you said 2 lamps per one, if they are 3ft 30watts each what wattage ballast would i need and same with the 4ft 36watts? (But surely the lamps would be to long for the fittings itself?

If you search for 1200 x 600 modular T8 fluorescent then you will find most are 36W tubes. There is normally hardly enough room to get the tube in place.
Magnetic chokes are becoming harder to get now but you would want a 36/40W choke like this.
For a twin system with HF electronic ballast you would be looking for a 2x36W electronic ballast like this, however they come in different sizes from different manufacturers and you would need to ensure you have space.
I do not know where you would get 2x30W ballasts but you can google it.
Check what you need first.

The Ghost · May 12, 2018

I've changed far too many fluors and you will find sometimes in 4' tubes there is one ballast. If one tube is not in correctly the rest wont work. Getting the bi pins to the precise position (quarter turn) is an art especially on older fittings. Also quite often it is easy to put in the wrong starter. And getting a quality starter is another little trick. It may be the tubes were not put in correctly or the starters are crap such as FSU universal starters which seem to work with nothing. There are different types of starters for single and double ballast tubes. I find Crompton s10 and s16 fairly reliable and seem to work ok. Denmans starters are a waste of time. So having checked that, personally I don't replace ballasts by the time I have fecked about taking out and getting the right ballast and putting it in to find it all still does not work as the end caps are damaged and the time to do it etc. it is cheaper to replace the whole fitting. In my case we have a store and plenty of fittings, high freq. to replace the older starter types. We are not allowed to put in old starter types due to someone suing for epileptic fits caused by a flashing/failing tube as H.F. fittings don't do that. Right that's enough now.