Led Tube T8 Retrofit: Single-Ended vs. Double-Ended

In order to reduce material and labor costs, a preferred way of replacing inefficient 32W T8 lamps is by removing them and installing ~17W LED tubes. These LEDs can come in several configurations.

The first configuration involves simply replacing the tube and reusing the existing electronic ballast. In this case initial manual labor is involved but the ballast would still require maintenance after its rated hours. Example here: http://www.usa.lighting.philips.com/products/product-highlights/instantfit.html

The second configuration is single-ended power and using an external ballast/driver. Example here: http://www.usa.lighting.philips.com/products/product-highlights/instantfit.html

A third configuration is single-ended power with no ballast needed. Example here: http://www.amazon.com/Hyperikon-841000701-Lig...33702&sr=8-1&keywords=t8+led+retrofit

Single-ended vs. double-ended:

Existing fluorescent lamps are typically double-ended power, meaning one side of the feed is hot and the other side neutral. The contact where the lamp is held in place is called the tombstone. Fluorescents use shunted tombstones, so that the two contacts on one side of the lamp are shorted together with no voltage difference between them.

The single-ended LED retrofit tubes with no ballast needed require the installation of non-shunted tombstones on one side of the lamp. In that case, hot and neutral are on the same side of the lamp.

I cannot figure out why manufacturers would not sell double-ended LED tubes that do not require a ballast, so that a bit less labor would be required in the replacement. They could just run the neutral back to the second end after passing the last LED on its return path. The shunted tombstones could be reused in that case.

It seems like safety is a concern but I can't find definitive explanations. Anybody have an idea?

If there are double-ended power LED retrofit tubes out there that don't require an external driver or existing ballast, please point me in the right direction. The only labor required in that case would be removing the ballast and rewiring. Then no periodic ballast maintenance would be required.

Please provide thoughts.

I have exactly the same questions. Apparently it has been more difficult to get the dual ended designs to pass UL and FCC. It may require extra circuitry for shielding or safety. These devices are now on the market and can be purchases from Amazon, made by
Hyperikon. They make both single end powered and dual end powered T8 LED bulbs. The dual end powered devices are $1.5 more per bulb.

My follow on questions are:

Which type dual ended or single ended power will win in the end? I only want to change my wiring once for my clients.

Why are they chargin more for dual ended power, is it to pay off engineering costs or are there component additions in dual ended power?

Tom

We are lighting equipment manufacturer, of course the following is our own opinion: we believe that double-ended is better because its inherent safety. Moreover, we agree with previous post stating that replacing old neon is easier.

We just designed a new line of products for replacing T8 tubes with G13 attachment, we have 60, 90, 120 and 150 cm lengths, 8 different colour temperature ranging from 2700K up to 6500K, internal ballast(so just feed Phase and Neutral to its ends) and efficiency up to real 150 lm/W (we use the latest 3030 Nichia chip LED with its 210 lm/W). Shortly these new devices will be available on our web site.

Michele

Try Hyperikon lights. They have single and double ended bulbs. Some of the single ended ones come with free tombstones.
https://hyperikon.com/product-category/led-tubes/

Thanks Karl. I remember being attracted to these Hyperikon lights. The website is put together pretty well.

Nowadays, more and more Chinese LED suppliers are having their Double-ended LED Tubes approved from UL. Beacause leakage issue has been fixed with a newly-announced IC, and two sides' leakage current (One is hot, the other neutral) less than 5 M.I.U. (5mA) which is compliant with UL's safety standard. In the near future, Double-ended Direct Wire Glass LED Tubes with UL win !!  We have a US warehouse and sufficient inventory of Double-ended direct wire tubes with UL DLC. Our inventory is helping  more and more  US project contractors win the bids. If you're interested, please contact me#  tony(at)igreenlumens(dot)com 

My company manufactures such tube lights. Unfortunately, we are present only in the marine market. In the marine (shipping) market, almost all the tube lights are double ended ones. I have not seen more than a couple of inquiries for single-ended tube lights so far.