What does F32T8/750 of light mean? - Page 1
Forum section: electronics / beginners

author: eeguy
author_rank: Regular Contributor
timestamp: September 09, 2023, 05:48:16 pm
content: Hello, the lighting in the kitchen suddenly dimmed. When I removed the cover, I found that 3 out of 4 lights are not working. They are long tube in shape. There is a F32T8/750 written on it. What does that mean?

author: IanB
author_rank: Super Contributor
timestamp: September 09, 2023, 05:55:48 pm
content: Fluorescent tube, 32 watts, T8 diameter, CRI 75 or greater.

author: CaptDon
author_rank: Super Contributor
timestamp: September 09, 2023, 10:18:50 pm
content: No fluorescent lights on Melac?? Should have just googled it instead of waiting for a reply here. Answer to next question, They're called ballasts and supply the correct current limited voltage to the lamps. Seeing that you have 4 lamps you most probably have 2 ballasts each controlling a pair of lamps. Lamps very dark or black on the ends, probably bad lamps, Lamps look like new but don't light, probably bad ballasts.

author: eeguy
author_rank: Regular Contributor
timestamp: September 10, 2023, 12:53:29 pm
content: All three fluorescent tubes have very dark/black ends. Home Depot is the closest. Searching "F32T8 750" has some products coming out but there is no mention about 750. How likely will they be compatible with mine?

author: eeguy
author_rank: Regular Contributor
timestamp: September 10, 2023, 12:58:11 pm
content: Quote from: IanB on September 09, 2023, 05:55:48 pmHow did you convert from 750 to CRI 75?If a product has T8 and 32 Watts written on it, will it be compatible with the one I have?

author: CaptDon
author_rank: Super Contributor
timestamp: September 10, 2023, 01:57:18 pm
content: Any F32T8 will be electrically compatible. Color is something of your choice. Daylight is not a warm color with almost no red output. Wood and flesh look sickly. Cool White and 4000K are nearly the same color and while a bit warmer still lack red spectra and yellows, oranges and reds just don't pop. Warm White, 3500K and 'Kitchen & Bath' are about the same in color rendition. Wood tones and flesh look more natural and fish with red and orange colors look really brilliant. BL is a non-filtered Black Light that looks mostly blue. BLB is a filtered Black Light that has a deep purple colored glass and the output is barely visible to the human eye. There are a lot of LED 'retrofits' available and most are designed to work with 'electronic' ballasts. They really don't work well with old magnetic ballasts that have very poor power factors. They probably won't work at all in fixtures that have a 2-pronged 'starter' and removal of the starter is a must. (1/4 turn twist counter-clockwise and the starter pops right out) If you go with LED retrofits some are 'Direct Wire' where you remove the old ballast completely. If you go the LED route select Warm White as the other colors are just far to sickly looking. The low wattage 'ECO' replacements are usually a poor compromise and tend to ruin the ballast over time. GE 'ECOLUX' and Phillips 'ALTO' are good performing low wattage bulbs. The Government is trying to make Fluorescent lamps obsolete due to lower efficiency than LEDs and also due to the mercury content of vapor lamps. Hope this helps!!

author: calzap
author_rank: Frequent Contributor
timestamp: September 10, 2023, 04:08:05 pm
content: The T in T8 stands for tubular, and the number is the tube diameter in eights of an inch. So, T8 is 8/8 inch (i.e. 1 inch) diameter. Most of 48 inch long tubes used with the old magnetic ballasts were T12 (i.e. 12/8 inch or 1.5 inch). T5 tubes were gaining popularity before the LED revolution in lighting. Not sure how much they’re used for new installations now.BTW, rebar in the U.S. is sized the same way. Number 4 rebar is 4/8 inch in diameter.Mike in California

author: IanB
author_rank: Super Contributor
timestamp: September 10, 2023, 05:37:31 pm
content: Quote from: eeguy on September 10, 2023, 12:58:11 pmThat's just the code. But a CRI (color rendition index) of 75 is not so good. Higher is better. For the nicest colors, look for a CRI of 85 or 90.As for the color itself, my personal preference is to go for warm white (color temperature of 2700 K, since I find higher color temperatures to be too cold and sterile).QuoteYes.Be aware that fluorescent lamps have been banned in California, and stock is already reduced in preparation for the ban coming into effect. So if you are in California you may find it hard to locate replacements.

author: calzap
author_rank: Frequent Contributor
timestamp: September 10, 2023, 09:25:37 pm
content: Actually, California is the second state to ban fluorescent lamps; Vermont was the first. Other states have bans pending. Likely CFLs will be banned for the whole nation pretty soon.I remember other lighting bans in California which by themselves had little effect or were counterproductive. It was the availability of more efficient lighting and the monetary savings that really drove the changes. About 25 years ago, California banned medium-base screw fixtures in new construction with the idea that fluorescent fixtures would become the norm. However, the small candelabra sockets were OK, and there was no limit on the number of sockets in a fixture. So, fixtures appeared with 3-4 (or more) candelabra sockets, and incandescent candelabra bulbs of up to 60 watts were readily available.I remember an apartment we had constructed in 2009. All the ceiling fixtures had candelabra sockets. Candelabra CFLs were hard to find and expensive. So after the inspection, I changed all the sockets to medium base and installed CFLs (now have LEDs). Another common trick at the time was to install a small cheap fluorescent fixture over bathroom mirrors for the inspection, then swap for a fancy medium socket fixture.The California law may help but will be easily circumvented for residential installations for those who want to. However, most folks like LEDs compared to fluorescent, so there should be little motivation to go around the ban. That was not the case for fluorescent versus incandescent lamps.The law makes sense for commercial installations.Mike in California

author: IanB
author_rank: Super Contributor
timestamp: September 10, 2023, 10:11:53 pm
content: I have T12 luminaires in my garage with Philips 3000K warm white tubes. I very much like the soft diffused light with lack of glare and shadows produced by T12 lamps. I can look at the lamps directly without any discomfort at all. Most other kinds of lighting produce shadows and are hard to look at without getting burnout spots in my vision. Hopefully the Philips tubes will last a long time.

author: Clear as mud
author_rank: Regular Contributor
timestamp: September 10, 2023, 10:17:11 pm
content: Quote from: IanB on September 09, 2023, 05:55:48 pmThat contains one error: The 750 at the end only contains ONE significant digit for the CRI. The other two indicate the color temperature. So, it means CRI 70 or greater, color temperature 5000 Kelvin.It's common to see the CRI digit as a 7 or an 8. Perhaps nowadays you could find a fluorescent tube with a 9, indicating 90+ CRI, but I'm not sure.(for fluorescent tubes) It's common to see the Kelvin temperature digits as 30, 35, 41, 50, and 65. Sometimes the colors are named instead of numbered:3000K is warm white3500K is neutral white4100K is cool white5000K is (I don't remember, someone else will have to chime in)6500K is daylight white (I think)

author: IanB
author_rank: Super Contributor
timestamp: September 10, 2023, 11:07:11 pm
content: Quote from: Clear as mud on September 10, 2023, 10:17:11 pmInteresting. The reference I found did not say that, but true enough the 3000 K warm light lamps I bought have a code of 830. The CRI is given as 88, which I think is quite good.Quote