New T8 LED fixture build questions

Old 05-04-18, 10:32 AM
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New T8 LED fixture build questions

Hello everyone. I have some questions regarding the replacement of the T12 fluorescent bulbs in my shop 4 bulb fixtures with new direct replacement LED bulbs. I have 6 of these fixtures to upgrade. These are what I've purchased. I bought 2 packs.

I chose these vs direct wiring to 120v because of cost.

Problem is, the department sales person told me these would work in my old fixtures with magnetic ballasts. He was wrong. I tried them. Then, I learned I had to replace the old ballasts with electronic. Fortunately, I found a newly listed ebay auction for 6 ballasts for $12. What a bargain. I already have them but haven't installed them yet.

Over the last week, as I have some bulbs left over, I also decided to replace (3) inline twin bulb T12 fixtures over my workbench, mounted to the bottom of upper cabinetry. However, to save money, I want to fabricate a simple fixture for 3 inline 4' single T8 LED bulbs. I just bought one (3) bulb electronic ballast for this project and I salvaged the medium bi pin sockets from an old discarded 4 bulb fixture. These will be mounted on a special 12 foot aluminum extrusion I have and the middle sockets will be installed back to back.

But here is the problem. I don't quite understand how to wire it up. I haven't received the ballast yet, but was wondering if anyone can link me to a wiring diagram for this? I tried to find one online but to no avail.

However, I have a couple of other questions. I was researching these medium bi-pin sockets on ebay, and found some that were described as "shunted". I've never heard of this before and thought I should find out if for some reason, the sockets in my fixtures might need to be "shunted" or not. I don't understand what this does in any case.

Another question is.. are electronic ballasts "instant start"? And, do they eliminate the typical dim bulb problem when they start up in the middle of winter? I would think so, especially using LED bulbs, but was just wondering.

Ok guys.. that's it. Thanks for any insight.
Old 05-04-18, 10:50 AM
PJmax's Avatar
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Those tubes won't work with a magnetic ballast. Looks to require an electronic ballast.
Shunted sockets would not be an issue as the pins get connected together anyway when converting to an electronic ballast.

In the long run you would have saved money by getting the direct wired/no ballast replacements.

Installation info...
home depot/catalog/pdfImages/27/27fd861d-0d67.pdf
Old 05-04-18, 03:40 PM
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For future reference and anybody else browsing here, Philips does make a T8 LED tube for T12 ballasts. Also, Feit and ToggLED have tubes that will operate off either type of ballast. Ditching the magnetic ballast will save more energy, but these are some options for anyone who doesn't want to rewire.

LED tubes will light up at full output almost instantaneously regardless of the ballast/driver type.
Old 05-04-18, 04:04 PM
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I would look for direct feed LED lamps and bypass the ballast entirely. Phillips, Keystone, and others make them.

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