T - 12 upgrade - Electrician Talk - Professional Electrical Contractors Forum

B4T · 03-04-2009, 06:21 PM

I have a customer who wants to change existing t-12 magnetic to electronic t-8. Will the t-8 fit into the same socket and do they even make 96" t-8 lamps?

**MDShunk** · 03-04-2009, 06:21 PM

Yes, and yes, assuming you're not talking about HO or VHO. I've done it many times.

B4T · 03-04-2009, 06:23 PM

Thanks Marc.. and it is a standard fixture

**MDShunk** · 03-04-2009, 06:30 PM

The 8 foot T-8's have only been out a couple years. When I first used them I mistakenly just assumed they existed. I went to the supply house for a case, and they told me there was no such thing. I'm like, "C'mon, seriously? Could you check"? They checked and found out that they did make them, but they were brand new out at the time. Now, they're regular stock. Tricky things to transport. I like to buy a whole case and just tote them in the case, even if I only need a few.

**MDShunk** · 03-04-2009, 06:33 PM

I remember something about what lampholders were directly across from each other being important when wiring the T8 ballast in the 8 footers, else it wouldn't work. I have to remind myself everytime I look at the ballast sticker. Seems like the white wire lampholder had to be directly opposite from the blue wire lampholder. That's just going off memory. Been a spell.

B4T · 03-04-2009, 06:41 PM

Thanks again for the info on the sockets.. I will check Advance for wiring diagram before I go to the job.

**MDShunk** · 03-04-2009, 07:00 PM

Quote:

Originally Posted by Black4Truck

Thanks again for the info on the sockets.. I will check Advance for wiring diagram before I go to the job.

I just went out and checked one of the ballasts (REL2P59) and I must have been remembering something else. The T8 change is easy on that one. Red to both lampholders on one end. Two blues, one to each lampholder on the opposite end. Nothing special. I'm not sure what I was thinking about. Maybe T12's.

John · 03-04-2009, 07:15 PM

I use GE-259-120-N ballasts for 8 ft T8's they cost less and are a little better quality.

**MDShunk** · 03-04-2009, 07:17 PM

How could they be better quality if they say GE on them?

John · 03-04-2009, 08:14 PM

Quote:

Originally Posted by MDShunk

How could they be better quality if they say GE on them?

Because they are C H E A P E R.

Or is this a trick question?

user4818 · 03-04-2009, 08:42 PM

Quote:

Originally Posted by MDShunk

The 8 foot T-8's have only been out a couple years. When I first used them I mistakenly just assumed they existed.

A couple years? We do regular maintenance on a facility that was retrofitted from 8' T12 to T8 back in the early 00's...at least that's the date stamp on the bad ballasts that we replace. Might even be 1998 or 99...I don't remember..but it's more than a couple years.

user4818 · 03-04-2009, 08:45 PM

Quote:

Originally Posted by MDShunk

I just went out and checked one of the ballasts (REL2P59) and I must have been remembering something else. The T8 change is easy on that one. Red to both lampholders on one end. Two blues, one to each lampholder on the opposite end. Nothing special. I'm not sure what I was thinking about. Maybe T12's.

When retrofitting from 8' T12 to T8 you have to disconnect the circuit interrupting lampholder circuitry and rewire it. It helps to cut off the wire from the old ballast because you end up needing it. I did a whole bunch of these recently and it's not cut and dry like a 4' conversion. You probably know this and you're just not remembering it.

rlc3854 · 03-04-2009, 10:12 PM

“We all are now enthralled by a great conflict for the emancipation of union members from the thralldom of an elitist caste which has thrown its shadows upon untold generations, and is now plunging the world into a tumult of the world’s electricians.”
The other 92.5%

Damn John, did you have to put it that way.

Wireless · 03-04-2009, 11:23 PM

Quote:

Originally Posted by MDShunk

I remember something about what lampholders were directly across from each other being important when wiring the T8 ballast in the 8 footers, else it wouldn't work. I have to remind myself everytime I look at the ballast sticker. Seems like the white wire lampholder had to be directly opposite from the blue wire lampholder. That's just going off memory. Been a spell.

The 8' T12's have the power go to the sockets and then the ballast while T8's go to the ballast first.

user4818 · 03-04-2009, 11:26 PM

Quote:

Originally Posted by Wireless

The 8' T12's have the power go to the sockets and then the ballast while T8's go to the ballast first.

You don't say?

Quote:

Originally Posted by Peter D

When retrofitting from 8' T12 to T8 you have to disconnect the circuit interrupting lampholder circuitry and rewire it. It helps to cut off the wire from the old ballast because you end up needing it. I did a whole bunch of these recently and it's not cut and dry like a 4' conversion.

B4T · 03-04-2009, 11:36 PM

Quote:

Originally Posted by Peter D

When retrofitting from 8' T12 to T8 you have to disconnect the circuit interrupting lampholder circuitry and rewire it. It helps to cut off the wire from the old ballast because you end up needing it. I did a whole bunch of these recently and it's not cut and dry like a 4' conversion. You probably know this and you're just not remembering it.

Will any electronic ballast for 8' lamps accept T-8 bulbs?

PS.. Peter...THAT was good to know.. thanks

user4818 · 03-04-2009, 11:41 PM

Quote:

Originally Posted by Black4Truck

Will any electronic ballast for 8' lamps accept T-8 bulbs?

PS.. Peter...THAT was good to know.. thanks

You're welcome.

As for the ballast, there is really only one popular setup that I'm aware of..the 8' lamp is 59 watts, and the ballast is a QE2X59 or REL259 or something to that affect, depending on who makes the ballast.

One thing about 8' conversions though - the ballast and lamps are MUCH pricier than comparable 4' components, so sometimes ripping out the 8' light and installing an 8' tandem with 4-T8 lamps is a better choice, depending on how easy it is to take down the light and what kind of condition it's in.