Ballast Question

River Rat Dad

I have been changing out all the flourescent T-12 bulbs in my church to T-8's.
New ballasts of course. It has been a slow process as it is volunteer work and I do it in my spare time. I am almost down to 9 fixtures that have an emergency back up ballast that runs a single tube in a power outage. I have not actually looked closely at one of these yet. Am I to assume the emergency ballast needs to be changed too in order to work with a T-8 tube?

mdshunk

You are correct, sir. The emergency ballast must be changed out to accomodate the T8 lamp(s) that will be served by it. If that existing emergency ballast has some age on it, chances are that the battery inside it is shot anyhow. They only last about 10 years or so. They're supposed to light the lamp for about 1-1/2 hours. People press the test button or turn off the breaker for a couple seconds, and see the light light up, and call it good. When these things get age on them, in maybe 5 minutes, the light will go out.

River Rat Dad

Thank you my good man for enlightening me. When I go on a search for these emergency ballasts is there anything I need to know? They only need to turn on one 48" lamp each, but some are in 2,3,and 4 lamp fixtures. Does that matter?

mdshunk

You don't need to know anything special, except at what voltage they are supplied. I would guess this is 120V, since you said it was your church. Emergency ballasts normally only do one or two lamp(s) in the fixture, providing you get the right ballast for however many lamps you want to backup. You'd just need to get a "regular" ballast to do the lamps too. These emergency ballasts should be stock or next day at your electrical supply house. I saw a couple at my HD a couple months ago when I was there, surprisingly.

Bodine is one of the old-time, popular manufacturers of emergency ballasts, but there are many others.


Almost forgot.... there are "time lengths" when you buy emergency ballasts. Most are a couple hours, but there is a special class that only give maybe 5 minutes for a bit of lighting while a generator starts. Just a head's up on that.

Here's the one I normally end up with, for no special reason:
http://www.bodine.com/apps/universal.html

K2

I'm used to seeing battery packs, (which look like a ballast ), used with whatever type of ballast I might be using. The battery packs i use have 14 leads comming out of them with detailed instructions with regards to instant start, or rapid start ballasts and the number of lamps you wish to have on the battery. Also an unswitched or constant hot circuit is required to run the battery back up I'm used to.

But I will say if you are messing with any type of lighting batteries and or disconnecting old batteries you should know how to arm / disarm them. They are a battery and can still knock you or someone else on your @$$ when you think they are disconnected, laying on the gound, in the scrap pile etc.

River Rat Dad

How much juice might be in one of those old batteries? How would I know if I'm looking at a "battery" that looks like a ballast or an actual ballast?

If this gets too complicated I could tell the church to get a professional to do the 8-9 fixtures with the emergency backup.
Getting electrocuted isn't on my list "bucket list"

K2

The batteries I see all the time are connected to a regular ballast and generally it looks like a massive mess of wires. .. I don't think the juce off the batteries will kill you but it would make you not want to do it twice. .. One option you might think about is mounting a frog eye over a lighted exit sign, (if you have one), and forget about the batteries in the fluorescents. Maintenance on a frog eye would be easier for future church members to understand.

mdshunk

The "battery" he speak of is the "emergency ballast". It does connect through the regular ballast. Click on my Bodine link and pull up the .PDF for that ballast and look at the wiring diagram, and you'll sorta get the idea.

K2

Oh, and don't forget to cap off your unused 120 or 277 lead because it can wack you or the next guy too.

Electric_Light

K2, I believe ALL emergency ballasts require an unswitched hot to allow the lights to be turned off by the wall switch. That's the only way it knows a power outage from the power being turned off by the switch, although for corridors and other uses with 24/7 burning cycle, you can jumper the unswitched/switched hot wires.


These things usually have a 6v NiCd, a special high temperature type usually 5x D size in a bar. If it was required by code, it should provide something like an hour of light IIRC.


Test button only tests that it's functional, not that the battery still provides adequate runtime. If it's 10 years old, replace it.

OP;
There are programmed rapid start T8 electronic ballasts, which is usually wired exactly like a T12 ballast but unless specified otherwise, the standard T8 electronic ballast is the instant start type with single wire per lamp end.

You need to make sure you've installed a jumper at each lamp socket to short across two pins. If you didn't, expect the lamps to fail prematurely.

K2

Should be able to use the the two existing leads from the lamp holder and tie them to the single leads of the instant start. But yeah if your using new unshunted lamp holders they need to be jumpered or have two leads off.

Electric_Light

Usually, there are four holes on rapid start sockets. All four holes are used on one of the yellow lead sockets, but there are two remaining holes on other three.

That said, cut two wires, strip both. Poke one into the hole right next to the other wire to form a jumper. Then connect the other wire to ballast. I think this is quicker than wire-nutting all 3.

K2

For the sake of discussion, on a regular ballast replacement the sockets are not easily accessible but the leads are. I think it's quicker to tie the 3 together than to start going after sockets. Or better yet, pop the three wires into a Wago. Of course all fixtures are different but most would be a pain to to the sockets.

If your doing a total gut and rebuild jumpering might be the way to go except that they make a socket/lampholder that is shunted or jumpered internally.