Converting fixtures from fluorescent to led tubes (with magnetic ballast)

sw_ross

Senior Member
Location
NoDak
My employer sent me on a service call to a restaraunt to work on some old t12 fixtures that were in the kitchen area. He sent me with enough Zilotek led linear t8 tubes to do all the light fixtures. These are a "plug-and-play" led tub that say they'll operate off of a magnetic ballast or an electronic ballast that is an instant start (-IS) ballast.

He also sent me with 3 of these ballast to have "just in case". The first three fixtures I put the new plug and play Zilotek's in lit up initially, but then (I'm assuming) when the ballast got hot they turned off, after the ballast cooled down a few minutes they would light back up again, cycling on and off every few minutes.

So then I changed out the ballast to the new ballast that I had, tested them out and they seemed to work fine after that! I still had more fixtures to work on, but no more ballast so I didn't want to keep going until I got more ballasts (or learned whether I had different options!).

Since then I was researching it online and saw a couple of lighting companies that promote bypassing the magnetic ballast and direct wiring their tube to the 120v available at the fixture (each company had a different technique for doing this). The Zilotek tubes that I had didn't say anything about doing this in the directions and I couldn't find anything online about it either?

It seems odd (and maybe wasteful?) to have to change out the ballast to get one of these tubes to work, also seems like a possible point of failure somewhere in the future? I would love to be able to bypass the ballast if possible! Anyone have experience with this scenario ?

Thanks for advice!
Sky
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
I don't think the T12 ballast will work with the LED tubes you brought. They are for T8 ballast.

Try looking at:
this site

They sell a ton of LED tubes which are straight line voltage.
Or they have "retro fit" that work with ballasts.
 
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sw_ross

Senior Member
Location
NoDak
Thanks! That makes sense! Duh! I was more focused on the fact that they were magnetic ballasts then the fact that they're for t12's and not t8's!

I'll check out the site you linked. Thanks!
 

JFletcher

Senior Member
Location
Williamsburg, VA
When doing LED replacements for 4' tubes, there is usually a list of compatible ballasts with which they work. If the ballast aint on that list, expect problems.

Personally Id rather use line voltage replacements and abandon the ballast in place but it's not always possible. Ballast is just another failure point to me; newer ones b/c they dont have the build quality of the old, and older ones just due to age.
 

sw_ross

Senior Member
Location
NoDak
I think I agree with you! Why put an led tube that's rated for 50k hours into a fixture and have it depend on a ballast that's probably not going to last 50k hours!?

Sounds like bypassing the ballast and using line voltage would be the simplest! Minimize the equation! It looks like some led line voltage tubes rely on a non-shunted tombstone, where the hot comes to one pin, and the neutral comes to the other pin at one end of the tube? And the other end of the tube the tombstones aren't used for anything except supporting the tube?

Also, altering the fixture I think would require some notification sticker for any future maintenance person that dug into the fixture- for safely reasons? I wonder if a fixture disconnect (that is normally required for ballast servicing by code) would still be required? Have to look into that!

Thanks!
 

sw_ross

Senior Member
Location
NoDak
Iwire - question

Iwire - question

Iwire, when you say led replacement, I assume you mean a dedicated led fixture and not a new fixture that uses led tubes?

I've seen led troffers advertised that look like they have an external driver on the top side of the fixture that you would run your MC feed into above the tile ceiling, with no serviceable parts inside the fixture. This looks like it would be a good option for new construction. Existing customers would have to be "sold" on the benefits of ripping their existing fixtures out and replacing with these troffers versus converting their existing troffers over using led tubes.

What "sales tactics" would you use for this purpose?

The fixtures that I'm working on are surface mounted and hard-piped, my employer decided the "least cost" option was to convert instead of replace.
 

James L

Senior Member
I've been changing over to l.e.d. at my son's school, an inside is a mix of t8 tandem strips and t12 wrap-arounds. I have experimental freedom there, so...

I first thought using a hybrid tube would be best, plug and play. But others here mentioned incompatibility issues with older ballasts.

I tried some single-end tubes with outboard drivers in a wrap-around. But that's not feasible with shunted tombstones unless those get changed too.

Then I tried some double-end tubes that run on 120v only, integrated driver. I hooked up all the yellow wires to neutral and blue + red to hot. Shunted or not, same same.

Then I tried some ballast-drive tubes (obviously double-end) with input range of about 80-350v. Same wiring configuration as the 120v tubes. I removed ballasts

Here's kind of my take. The more you can separate the driver from the l.e.d.s, the better. Outboard driver is almost certainly going to last longer than a tube with an internal driver. But there's a tradeoff.

If you do a conversion kit and a driver fails, it's like changing a ballast. If you do an integrated fixture (panel or troffer) and any part of it fails, you have to change the driver or the whole fixture. In short, the future maintenance will almost certainly require an electrician. But these methods will probably go longer before experiencing problems.

With the line voltage tubes, you can be done at conversion and future maintenance is simply swapping bad tubes. This is where I'm at with the school. If a tube goes out, it just needs a new tube. But they've crammed a driver inside that tube. Not as much heat dissipation, so it'll certainly fail sooner.

I've also tried cheaper tubes and more costly tubes, and there's a difference. The cheaper tubes are made with less aluminium, so they retain heat more. Less expensive initially, but more frequent failure.

If you get a tube that's listed somewhere (UL, DLC, RoHS) you're almost certainly going to get something with decent quality. With all the submittals required, it's just not something somebody's gonna go through to be able to market junk.

As for marketing, I'm thinking Return On Investment would be a big factor. Energy savings and less maintenance = more payback. Do the math and let the numbers talk
 

sw_ross

Senior Member
Location
NoDak
Appreciate the insights, experiences, and perspectives! Thanks.

Just ordered some line voltage tubes and some non-shunted tombstones to get some experience with that option.

I agree that a Return on Investment/lower future maintenance costs is a good sales technique to use. Especially if you're doing something off a lift that is involved with getting the lift positioned (like a gymnasium)!
 
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