Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[dave w]

Off topic but anyone remember the old Carver "cube" amps of the 1970s?

[bkenobi]

I have a 2 tube fixture hanging from floor joists in my basement that I was planning on shifting over my workbench this evening. The bulbs usually require the touch lamp treatment to illuminate, so I was also going to replace the tombstones. When I pulled the metal chain from off the nail and put it in the new location, I noticed some arcing. The chain was in slight contact with some HVAC ducting so figured maybe dissipating off static I built up or whatnot. I adjusted things and the arcing happened again and but this time.

Hmmm, strange.  Perhaps the ground was bad.  I pulled it down and unplugged it. The previous owner used a light socket splitter plus duplex adapter to plug a non-grounded fluorescent fixture in.

So, my question is, can I just swap the pigtail for a grounded one. The wiring diagram doesn't show a ground so is it required? I may just dump it and get a new one if I can't confirm a safe setup.

[Brian H]

I have see some of the magnetic type ballasts labels marked should be grounded. Even if it was not shown in the wiring diagram.

All the later electronic ballasts I have are clearly marked must be grounded or unwanted events may happen.

The swiping the tubes to get them to light Could be you providing a capacitive ground.

You should be able to ground the lights if you care to or use this as a excuse to get new ones.

[dhouston]

http://chemistry.about.com/od/chemistryactivities/a/Fluorescent-Light-Science-Experiments.htm

[bkenobi]

I have a new fixture in a box I could install.  I have some that were kept as backups when my dad got rid of his unused pallet (failed shop lighting project).  If I keep the current fixture, I am primarily concerned that a ground should be for backup safety and if it's arcing/sparking/shocking, it must have a fault.  If so, adding a ground would just electrify the ground network which seems like a bad thing.

The ballast is labelled class P type 1 and is rapid start.  It looks pretty old, so I'm assuming it's magnetic start.  The diagram does not show ground.  I tested continuity this morning and found no connection between any of the contacts and the case so I assume there is no short in the wiring (worn insulation).  I assume also that there is no permanent failure within the ballast since continuity was not present.  To me (ME not EE) this means that if there is power on the chassis when energized, something inside the ballast must be faulty especially since it requires a hand wave to light.  If that seems like reasonable logic, I guess the choices are installing a new ballast or a new fixture.

I went through this earlier this year with a different fixture and found that the ballasts at the box stores created X10 problems.  I have some fixtures like my spare installed in the garage and other than creating issues on that run, they do not affect other X10.  In that case, the issue was the tombstone, so I returned the ballasts.

I am leaning towards just installing a new fixture or looking at the LED unit at Costco.  Power usage will never pay for the fixture (it's not used that much), so this is really a question of installing something that isn't a safety issue, provides sufficient light where needed, and not breaking my X10 stuff.

[Brian H]

I believe the spark you are seeing is just a static buildup between the tube running at a high voltage from the ballast and the metal fixture frame. Grounding it should not cause a problem and maybe even make it start more reliably.
Just test the LED fixtures if you go that route. They may possible cause X10 issues. depending on their drivers design.

[bkenobi]

If it was just a spark, I wouldn't have said it bit me.  This was definitely a continuous shock though it did not pop a breaker.  I don't know if I should be able to measure a voltage from the contacts to the chassis on a functioning unit, but I definitely see 120vac on some of the contacts to the frame.  It seems to me, if ground was not needed (ballast was not grounded), there should be no connectivity and no power should flow.  Again, I'm not an EE and don't know how the ballast is designed or should function other than the light should turn on when powered.

I stopped by my local hardware store to ask an electrician about it.  They said it sounded like a faulty ballast and it would be cost prohibitive to fix.  He pointed me to a stack of LED shop lights that were supposed to be $29.  I would have bought it but it rang up as $49.  A new ballast is ~$10-15 as I recall.  I'll check Costco and the box stores for LED fixtures and give them a try.

BTW, do the LED fixtures require a ground?  If not, I could just plug it in to the duplex as configured now.  If not, I'd have to swap the fixture to one with a grounded plug in it.

[Brian H]

From your description. I does sound like the best thing to do is replace the fixture.

I would expect all present day electrical devices to show a safety ground if hard wired or have a three prong electrical cord on it. I can't say if an LED fixture would work without the ground connected. Probably would just not having a safety ground to meet present electrical specifications.

I use some replacement LED tubes in my original fixtures. The ones I used had the ballasts cut out and 120 VAC was wired directly to the LED replacement tubes tombstones. I don't believe the instructions mandated a ground but may have recommended it for safety. The tombstones could not have both pins internally tied together as Line went to one pin and Neutral went to the other pin on the same end. The opposite end of the tube had no connections. I have seen other brand LED tubes wire Line on one end and Neutral on the other end. Some are also made to be directly driven by the ballast and need no rewiring.

I had one fixture where the replacement tubes where not a good fit. They had tombstones pointing 45 degrees from vertical.
Light shined out the sides as the LED tubes do not emit light all 360 degrees like a fluorescent tube does.

I found they where brighter than the old fluorescent tubes where. Since the light was in only one direction even though their Lumen ratings where lower then the old florescent tubes.

[bkenobi]

So are the complete LED fixtures or gutting and installing an LED bulb better/cheaper/less problematic for X10?  The fixture isn't pristine but it's a basement workbench so it doesn't get seen anyway. Light, safety, X10, and to some degree cost are more important factors than looks or energy savings.

[Brian H]

So are the complete LED fixtures or gutting and installing an LED bulb better/cheaper/less problematic for X10?  The fixture isn't pristine but it's a basement workbench so it doesn't get seen anyway. Light, safety, X10, and to some degree cost are more important factors than looks or energy savings.

I can't give you exact information.
It would depend on the exact replacement LED tube if retrofitting an old fixture. Or the electronics in a totally new replacement fixture.
I did test my Naturled 5775 replacement tubes. They didn't make any noise on my XTBM or show any signal sucking when connected to the outlet where the XTBM was signal testing.
They do not have the same Lumens output as an florescent tube. But the output is 120 degrees beam width over the old fluorescent tubes 360 degree beam width. So in the light field they are brighter to me than the older ones they replaced.
Here is some information on the LED tubes I used. The need for non-shunted tombstones is pointed out.

[dhouston]

This is pure speculation but, for the past 6 years I've lived in a 3-room apartment in 4-unit building that is about 50-60 years old. All of the original wiring lacked a ground wire but over the years grounded outlets have been added for window AC units and for kitchen appliances. The bathroom has a recessed medicine cabinet with integral fluorescent tubes beside the mirror and an ungrounded outlet. The metal cabinet itself was grounded. When the ballast failed a couple of years ago, a new one would not work until it was grounded (to the metal cabinet). From this, I surmise that older ballasts were ungrounded but newer ones need a ground.

[dhouston]

So are the complete LED fixtures or gutting and installing an LED bulb better/cheaper/less problematic for X10?

It's the switching power supplies used by the LEDs that cause problems (noise or signal sucking) so it's impossible to generalize - some are OK for X10 but you need to know whether any X10 users use the exact make/model without issues.

[bkenobi]

It's the switching power supplies used by the LEDs that cause problems (noise or signal sucking) so it's impossible to generalize - some are OK for X10 but you need to know whether any X10 users use the exact make/model without issues.

Which makes it difficult to pick something in a timely fashion without over buying multiple items hopefully from a site with free shipping and good returns. I forgot the difference in types of tombstones. I'll have to verify what type mine are.

[bkenobi]

I removed and then reinstalled the ballast from the fixture thinking perhpas there was something obvious going on with it (nope).  When I plugged it back in for testing, it seemed to work correctly but I didn't trust it would stay that way since I couldn't determine the initial fault.  When I had it apart, I found that it used the same ballast that I had in my spare fixtures.  I thought about just swapping in the ballast, but decided the new fixtures looked cleaner.  The interesting thing is that this ballast (both new and old) have markings stating grounding is required.  I wonder if not grounding over however many years it was in service may have caused an issue.  Either way, the new one is up and causes no X10 issues.

I almost bought a new fixture at Costco since they were only $30 including the LED bulbs.  If I didn't have the fixtures and bulbs already, going LED would have been close to a wash since the fixture is $15 and a pair of bulbs is $10 these days.

[Brian H]

Glad you have a working fixture now.
Difficult to say if running with no ground effected the ballast. May have contributed to its failing.