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My facility is in the process of replacing the fluorescent T8's with Eurilight ET8-1150H's. While doing some energy and RF testing I found that the aluminum heatsink, which runs the entire length of the tube, was carrying voltage.

I have found voltages in various fixtures from ~20VAC all the way to 277VAC (in 277 configuration) and similar results in ballasted configuration. Voltage is being measured between the heatsink and the luminaire's metal frame.

The tubes display the same results whether in opposite end fed or same end fed configurations, typical of a hybrid. The tubes have similar results when put directly into ballasted single or double configurations. I have more testing (sample size) to do on the ballasted ones, but I am quite dismayed by what I am finding so far.

This cannot be right. This is exposed and should be at ground potential. I have never come across a piece of equipment which had (by design) exposed metal at line potential.

I am having an email discussion with someone who is relaying for an engineer. They want video...I am thinking of punctuating the meter test with a lightbulb connected between the heatsink and the frame.

Comments?
 

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Just trying to get home
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Discussion Starter #3
Wiggy or Fluke, same result.

Oh, except at the output of the ballast. Fluke (43) wins there since the Wiggies usually have too low impedance.

I'm...glad you like my other avatar...?
 

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In best Indian Accent (dot) : I like a lot of things........
 

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Just trying to get home
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Discussion Starter #5
Yah, I get that...I guess...not really sure where you are going with that...:001_huh:

I save the rhetoric for the Controversial Talk section.

I was looking for electricians who could help.

Thanks anyway.:thumbsup:
 

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Discussion Starter #6
Use a wiggy next time.
Oh, I see. You got that from my Disqus account. Yeah, I use a different avatar there.

Still...not sure why you went to all that trouble.

The Indian accent has me confused though.:red_indian:
 

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Was no trouble at all, rather accidental actually. Surfers rule
 

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So, there is a real voltage there and not just ghost? Can it power a load? Have you had a helper touch it?
 

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I have found voltages in various fixtures from ~20VAC all the way to 277VAC (in 277 configuration) and similar results in ballasted configuration. Voltage is being measured between the heatsink and the luminaire's metal frame.

The varying voltage does suggest induced voltage

This cannot be right.
You betcha ! :eek:

I am having an email discussion with someone who is relaying for an engineer. They want video...I am thinking of punctuating the meter test with a lightbulb connected between the heatsink and the frame.
If it does light up, it's real power .... Post the video here ! :thumbsup:
Comments?
__________
 

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Discussion Starter #12
it doesn't seems ok but same problem that can happen with any led fixture that have a metal heatsink.
???

Really? :blink:

Why is that? Why would a manufacturer/designer do such a thing?

Down here in the U.S., I would start with specifically referring to the NEC :

410.5 Live Parts.​
Luminaires, portable luminaires, lampholders, and lamps shall have no live parts normally exposed to contact.
I assume that the CEC has a similar code section.
In one scenario I can imagine, a store owner puts these T8's in their display cases where the customer could easily be shocked by them. It just seems so ludicrous.

 

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I still say it is your meter, cause there is an overcorrect device that is going to be noticing the issue, or else probably some smoke coming out of something or another.
 

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Discussion Starter #14
So, there is a real voltage there and not just ghost? Can it power a load? Have you had a helper touch it?
Well, yeah...there is real voltage there.

I can light a bulb between the heatsink and grounded parts of the luminaire.

No live subjects, yet.:whistling2:
 

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Discussion Starter #15
I still say it is your meter, cause there is an overcorrect device that is going to be noticing the issue, or else probably some smoke coming out of something or another.
The heatsink is not bonded, so it's an exposed terminal. It doesn't pop any breakers that way.

When I conducted the test with a light bulb it only worked for a second, then the unintended path in the tube's SMPS went to sh!t in a loud/magic-smoke-release kind of way.

Very exciting.

This brand/model of tube is hazardous.
 

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Discussion Starter #16
I second that. Im interested in see your findings as well.
Here are some of my test results:
------------------------------------------------------------------------------------​
These are just initial findings. I haven't compiled a table for the ballasted fixture tests yet. I am finding similar conditions there, just at the driven frequency from the ballast.​
 

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I think you said heat sink wasn't bonded(bad design imho). I guess what you really need to prove is touch potential. FWIW quick fix/ temporary fix run bond jumper?
 

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???

Really? :blink:

Why is that? Why would a manufacturer/designer do such a thing?

Down here in the U.S., I would start with specifically referring to the NEC :

410.5 Live Parts.​
Luminaires, portable luminaires, lampholders, and lamps shall have no live parts normally exposed to contact.
I assume that the CEC has a similar code section.
In one scenario I can imagine, a store owner puts these T8's in their display cases where the customer could easily be shocked by them. It just seems so ludicrous.

i said that because most of led bulbs doesnt have ground pin so we cant ground them, but the heasinks are supposed to be floating, if you have voltage on it it is defective.
 

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Discussion Starter #19
I said that because most of led bulbs doesnt have ground pin so we cant ground them, but the heatsinks are supposed to be floating, if you have voltage on it it is defective.
I think you said heat sink wasn't bonded(bad design imho). I guess what you really need to prove is touch potential. FWIW quick fix/ temporary fix run bond jumper?
Touch potential has been proven on my part.

When I bonded it the magic smoke got out.

This isn't phantom voltage, it's just a bad design.

I will be reverse engineering the SMPS inside the tube, if not for my own curiosity, then to better report it to my safety department as to the root cause. My guess is that the negative side of the power supply's output is supposed to be floating. Since the LED assembly is mounted to an external heat sink it presents an issue.
 
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