Does anyone know the long term effects of using T12 lamps with a T8 electronic ballast or using T8 lamps with T12 magnetic ballast?
I know they will work, at least in the short term.
The other thing I wonder about is on the diagram for the Advance electronic T8 ballasts it shows the bipin sockets shorted together. Does anyone know what the long term effect would be if that was not done. I know they make preshorted sockets but I do not have any right now.
This came up in an argument between me and a maintenance man that stated "they work just fine" when he mismatched the lamps and ballast. My response was "yeah for now". However, I have no real ammo except the label on the ballast.
I have seen this many a time.. like you said they will work "for now" but while doing so you will probably not be getting the correct light output, and its hard on the bulb and ballast.. As for " shorted" endsockets.. What we do if we are converting a fixture over to T-8 is to "short" them ourselves.. ( wire the 2 leads from the endsocket to the single wire from the ballast).. works fine.. Our local convention center is wired like that... I do not know of any long term effect if the sockets were not " shorted".. Possible hard starting of the lamp maybe, or premature failure of the electrodes in the lamp is all I can think of really...
#62908 - 03/02/0607:45 PMRe: Mixing T12 and T8 ballast/lamps
Here's what I found on a trouble call. 2 yr old Church. 5 2x4 lay ins, Customer rebulbed all, none would work. Opened the first fixture, removed 4 T12's. & found an electronic ballast, requiring 4 T8 tubes. Had to replace all 5 ballasts, & replace tubes. These fixtures were in the main entrance, so they were on anytime the Church was occupied, so they failed first. 96 fixtures in all, & everyone had T12 tubes installed. Ordered a truck load of T8's to replace all of them. Needless to say, They were not very happy with the Electrical Contractor that made this mistake.
#62909 - 03/03/0609:11 AMRe: Mixing T12 and T8 ballast/lamps
Be very careful when playing with T8 lamps and instant start electronic ballasts. There have been documented fires caused by mis-wiring of T8 equipped fixtures.
You must enure that the pins are shorted together. If you do not have shorting sockets then short the conductors going to the socket together. Not doing so has caused at least one fire, that we know of, in a Canadian jurisdiction. The fire was caused by charring of the tubes due to excessive heating of the lamp cathodes due to high current.