Upgrading shop lighting

[Tom Sullivan]

   Today I had to replace a ballast and several bulbs on my old T-12 8' fluorescent lights in my shop.  I have a total of 15 eight footers in my 2,000 sq' garage, and started thinking about upgrading to T-8's.  But going from 75 watt to 59 watt bulbs really doesn't seem like enough improvement based on my experiences with CFL's in the house.  I started wondering.  What if I replaced those 75 watts lights  (two per fixture) with a couple 14 watt CFL's (60 watt equivalent)?  Those 60 watt equivalent CFL's seem brighter than the 60 watt incandescents, and that would take the garage lighting down by 80%.  Even if I went to the next larger size bulb, the savings would still be substantial.

   I looked back on this lighting group and found no discussion of this nature.  I also looked on line but could not find anyone every discussing this option.  This would eliminate those "PITA" ballasts.

Any thoughts from the experts??

Tom

[DanG]

T-8's with the correct electronic ballast will equal or better the old T-12s at the reduced wattage - a rule to follow is the narrower the tube, the higher efficiency; unless you had high-output ballasts and were cooking the T-12s. Example: There are high-output 8-foot 86 watt T-8 bulbs that will pump out 7,600 lumens; to match that output in a 96" T-12 would take 110 watt bulbs. BUT the ballast has to be tuned to the circuit, relamping with T-8 bulbs using a T-12 vintage ballast can produce erratic results.

Take care selecting ballast and bulbs from manufacturers products matrix, all the lumen outputs - wattage inputs are provided. To get the most from your current fixtures may mean swapping the holder-socket types to single pin or the high-output nub style. If you want real light look into T-5 bulbs, very pricey. I've re-ballasted 96" fixtures with electronic ballasts but the homeowner declined buying the T-8 bulbs so the T-12s were reused and they never appeared to really light if you know what I mean - even and instant light but just not dazzling bright.

If you have voltage transients, brown-outs on equipment or A/C start up or lightning or other spikes, or dead air-space allowing over-temperature, you need to find out what is reducing the life of your current ballasts! Also, know the CFL ballasts are extremely more likely to be affected by supply or location problems than the mature canned ballast types. My opinion on CFL's is they are hit or miss on quality, and definitely do not tolerate short run times like flicking on lights for a few minutes only.

[Tom Sullivan]

Dan,

   I'm familiar with the T-8's and T-12's.  At one time my whole dealership had T-12 lighting in the shop area.  Under a rebate program with my local utility (must have been 15-18 years ago), we replaced every fixture with new T-8 fixtures.  That's where I came up with the free T-12 fixtures for my home shop area.  I theorized then that my reduced "on time" of the home shop lighting justified reusing those lamps.  During my last major dealership expansion we went to high bay lighting in the shop and reused most of the T-8 fixtures our new parts department.  I have a few of the T-8's left over that could be used in my home shop.

   I totally understand the ballast must match the lamps.  Most the ballasts I've replaced (3 or 4 in the last couple years) have been the old magnetic ones, so I assume they were original ones (those fixtures were originally purchased in 1985).  I've got a few more of them that are humming pretty good, so they are due for replacement too.  Every fixture IS single pin, so could I just replace the ballasts, upgrading to T-8, and relamp those fixtures with T-8 bulbs?  I've never noticed a difference in the fixture sockets?

   At this time, almost every T-12 bulb has discoloration at one end (or both).  You mention circumstances that degrade bulb and ballast life.  The recently removed Breezy wind turbine created spikes in my power every time it kicked in.  I could actually see lights flicker.  Maybe that had some impact on the lighting in my workshop.

Tom

[bj]

   Tom   while reading your post, I saw an ad on the bottom of the page for ecopower.net.  They make a fairly full line of LED
tubes for replacement in existing housings.  It was interesting to me, as I am having the same sort of problems with lighting.
   They had no pricing on the info--you/I would have to contact them.  Might not be what you want, but thought it was worth
a mention.

[DanG]

Available white LEDs currently can reach over 20% efficiency without their regulated power supply losses included. Add in PS losses and while better than T-12s (9%) they are still under a well matched T-8s fixtures efficiency (12~15%).

Tom Sullivan - are/were any of the humming or bad ballast (old) lamp tubes glowing pinkish at the ends? I've read where waveform distortion places a 'net' DC bias that will exhaust the Mercury arc carrier and the pink is from the primary Argon fill gas taking over conduction. The Mercury precipitates out into/on the glass but most of the tube base discoloration you are seeing is the tungsten alloy filaments getting sputtered away. The pink glow is usually a token sign on CFL's that its ballast-inverter is a cheap design.

And as to the pin sizes I've not been around enough of them to know, but the pins probably have a hard coating protecting the metal from arcing and corrosion that may also be nearing end-of-life. I know on the high voltage sections of laser printers the removable drum contact pads are their weak link and print quality rapidly degrades if they've seen contamination arcing and cleaning them repeatedly removes their shield coating so its a downhill spiral. Vintage hand-me-down fixtures and oxidation at those points of contact might be a small part of the problem if the tube is seeing that DC-bias and killing lamps.

[dnix71]

We went from 75 watt to 60 watt T12's in the shop in Feb 1992 as part of a utility rebate program. The 60 watt "energy saving" tubes required a slightly higher starting voltage and many of the ballasts had to be replaced at the same time.

The magnetic ballast for T12's with a single pin at the end has a fairly well known major design flaw.
If you try to burn the tubes until they fail it will fry the ballast if one of the tubes fails first. One of the clips is a power disconnect. It has two wires inside like this ) (   When you insert the tube it connects the line to the ballast.

If one of the tubes fails first the magnetic ballast will go into start mode and cook itself. If the other tube fails first, nothing bad happens. I can't remember which tube is critical, the line disconnect or the other.

The line disconnect is absolutely necessary for user safety. The start voltage on a 8' T12 is 780v.
Without the line diconnect the ballast would still be live when changing tubes. I've been shocked changing 4' 40 watt T12's. That made my chest tight. I was standing on a desk so I just pulled my hands back and stood there for a little bit. Then I told the secretary I would need to turn off the lights in the room to finish changing the tubes in that fixture.

[12AX7]

Sorry,   I can't get past...."2,000 sq' garage"

Sure would love to have your lighting problems!

ax7

[Tom Sullivan]

   I only mentioned the size of the garage to establish the amount of lighting I have.  I will mention though, it's really not too bad to heat, and is cool in the summer, as I built it underground on all sides except the garage doors.  Some of my neighbors call it the local bomb shelter.
   I think I am going to start upgrading the fixtures, a few a time to T-8's.  I have 3 removed ones from my dealership I can use to start replacing some T-12 fixtures right now.  Based on conversation with my local electrical supply house today, it appears the "pin type" fixtures can be upgraded from T-12's to T-8's with just a ballast and bulb change.  I'm getting quotes on ballasts and complete fixtures to see if it's economical to upgrade existing fixtures.  Seems most times it's just as cheap to buy a whole new fixture.

Thanks for the feedback.

Tom

[ghurd]

I do like the LED bulbs for task lighting.
Never quite have enough overhead light in the right place for the drill press, or bandsaw, or...
They make more light for the power than mini-CFLs, like my 1.2W 5mm LED bulb makes more light than my 3W CFL.
G-