@mazeteam I completely 100% Disagree with the statement where you say electronic ballasts for fluorescent are reliable! I remove them on a daily basis and most schools and shops I look after request that i put switch start back in, Most HF fittings that I have to repair are still fitted with the original lamps a lot of the time I convert them back to switch start. It is common that the lamps out last the ballast on HF!

This to me is just never right! Infact, I just took one out last job today PC258HF Pro, blown up original fitzy lamps. I have a box back at my office with over 1500 in! I have had T5 fittings fail that have done a whole 2 months service! Some are more reliable than others but in general if you get 10 years out of them you have done well...Very well.

Then on the other hand there is a school sports hall I look after, that has 130 8 Foot 125w Fittings installed in 1971, I have looked after these lights for 10 years and NEVER had to change anything more than a tube and starter when I have lamped up! As for the Harvard electronic ballasts for SON/HM/CDM, I fitted 6 in 2006 in a shop in Plymouth, had to go back there last week as 3 fittings were out. All 3 were dead ballasts. Original Philips Master CDM-TC lamps! I left the same lamps in and changed the ballasts just to see how much longer the lamps have in them. MAGNETIC FTW IMO!

I would guess a lot of it is due to the design of the light fitting and how well (or not) it dissipates heat. If the light is on the ceiling and the ballast is at the top of the fitting then the heat from the lamps will rise and accumulate at the top of the fitting and overheat the ballast - same goes for battens with electronic gear. I expect where the ballast is fitted below the level of the lamps, preferrably in some sort of discrete heatsink, then you wouldn't get a heat buildup and the ballasts will last longer.

On a local hall I had been overseeing maintenance for a number of 600x1200 and 600x600 box lights (with a combined lamp useage of roughly 200), and in the last 10 years there had been about 8 ballast failures. Notably most of the ballast failures were occuring at the start of my tenure as the previous person who was supposed to keep an eye on the lights just left the tubes to flash until they died, still using glow starters, and so this eventually burns out the ballasts... whereas during my term I put in glow starters and got a much lower failure rate (2 went), although this wasn't helped because people kept turning all the lights on at the exact same time and so the current drain meant a few of the starters wouldn't operate, and so it was believed some of the starters had failed and so behind my back a load of them were changed over for glow starters (and not too long after that we got the aforementioned 2 ballast failures). To be honest I've just left them now and if those who went behind my back don't realise they're slowly destroying their own lights then so be it. Quite why you need 4x 36w tubes in a fitting with reflectors that's 2.5m from ground level I don't know... the ceiling is just as well illuminated as the floor which is quite a feat considering the lights are recessed into the ceiling.

Anyway I digress... the point I'm making is that with fluorescents you can have just as unreliable magnetic ballasts as you can with electronic, it all comes down to what brand you use, how well designed the fitting is, and whether you somebody competant doing maintenance on the lights or a complete spanner. If I was specifying ballasts for fluorescents I would always use either Philips or Tridonic...

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