T12 replacement
- Thread starter olc
- Start date
- Status
kwired
Electron manager
- Location
- NE Nebraska
The later years when magnetic ballasts were still common - I thought they took a terrible dive in overall quality.
I had replaced "replacement" ballasts several times in two ballast fixtures while the second ballast was still an original and still working.
34 watt lamps didn't seem as reliable either as the 40 watt lamps were, and were much worse at strange flickering until warmed up.
ETA: those that came in fixtures marked for residential use only were even worse then the "standard" ballasts were.
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Electric-Light
Senior Member
Magnetic ballasts are durable but rapid start systems are picky. they're meant to have a couple of volts applied at each bi-pin and also require good grounding and good connection between ballast case and fixture chassis. Shifted sockets, bent socket pins, corrosion, poor bonding between ground, fixture chassis and ballast case or loose wires can all cause the issue you described. In other words, they're so reliable that its not uncommon for lamps to remain in place for over a decade until corrosion starts to cause problems. How were the old lamps? Filament only runs at a few volts so a high resistance connection will cause inadequate heating. Two lamp circuit runs two lamp in series, so if one drops out, they both drop out.
Also 34WT12 or 48" 25W T8 produce less heat while preferring warmer temperature than full wattage lamps. They're meant for indoor use or at least enclosed in wraps where lamps are exposed to cold breeze.
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- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Some ballasts and fixtures were specifically labelled as NOT recommended for use with 34W economy bulbs, just the original 40W version in the same size.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
If these are not HO T12s, its so easy just to install T8 ballast and lamps. (Provided you keep them in stock)Don't even have to mess with the tombstones.
If you're changing to T8 you better "mess" with the tombstones as far as the wiring goes. The T8 needs the sockets shunted so you have to modify the wiring to the tombstones.
Electric-Light
Senior Member
If you're not getting a couple volts across each of the sockets, you're not going to get it working reliably and of course they have to be in good shape and let the lamps seat correctly. Socket problems are more likely. It's often the aging poke-in wire traps or sockets that don't stay in place and tend to move away from lamps. The ballast is shot for sure only if you're getting no continuity across the same color leads on a magnetic rapid start directly at the ballast leads. The good old Made in USA magnetic ballast seldom fails in residential use if they're not incorrectly installed. New sockets on freshly stripped wire ends, new 40W lamps and the system should be good for the foreseeable future.
You can still easily find full wattage 40W T12 in retail stores. They all have CRI 87 or higher these days.
This low lumen F40 sold in retail stores is actually a full spectrum lamps tuned at 4100K that emits all the way from near ultraviolet to deep red. CRI is near 90 and R9 approaches 70. Pair these with electronic ballast and you have a excellent quality light that is unmatched by essentially all LEDs out there. This stomps all over LEDs except for very expensive professional color matching products and even those have a spectral flaw between violet and blue. 4100K looks like any other 4100K on white or beige surfaces but colors like strawberries and Ferrari Red are rendered brilliantly along with complex bluish green colors LED lighting can not render. You wouldn't be disappointed. The higher lumen versions have almost the same CRI but R9 is not included in CRI and the R9 on the higher lumen versions aren't impressive.
Since having the highest lumens per watt is not the highest priority in homes, this is a significant light quality upgrade over just about any LEDs you can commonly find today.
You end up getting like 40 lm/W but the CRI is close to 90 with R9 red rendition nearing 70 and this is at a level only the LEDs marketed as super premium critical color rendition will hit. These lamps are not stocked at supply houses, because they're meant for household use only.
You can still easily find full wattage 40W T12 in retail stores. They all have CRI 87 or higher these days.
This low lumen F40 sold in retail stores is actually a full spectrum lamps tuned at 4100K that emits all the way from near ultraviolet to deep red. CRI is near 90 and R9 approaches 70. Pair these with electronic ballast and you have a excellent quality light that is unmatched by essentially all LEDs out there. This stomps all over LEDs except for very expensive professional color matching products and even those have a spectral flaw between violet and blue. 4100K looks like any other 4100K on white or beige surfaces but colors like strawberries and Ferrari Red are rendered brilliantly along with complex bluish green colors LED lighting can not render. You wouldn't be disappointed. The higher lumen versions have almost the same CRI but R9 is not included in CRI and the R9 on the higher lumen versions aren't impressive.
Since having the highest lumens per watt is not the highest priority in homes, this is a significant light quality upgrade over just about any LEDs you can commonly find today.
You end up getting like 40 lm/W but the CRI is close to 90 with R9 red rendition nearing 70 and this is at a level only the LEDs marketed as super premium critical color rendition will hit. These lamps are not stocked at supply houses, because they're meant for household use only.
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