Fluorescent lightig saniity check

[Jerome Hanby]

Iv'e got all my fixtures cleaned and repainted. Wired up the first one the other night. Using 8 brand new sockets and one 4 bulb electronic T8 ballast. I'm using 4 daylight (6500K) 34 watt Phillips bulbs. Wired everything according to the diagram on the ballasts, installed the bulbs, and fired up the fixture. I had one bulb that didn't seem to be working too well, but I swapped in a new bulb and that problem went away, That "bad" bulb in a different position still had problems, so I concluded I had one bad bulb out of the box, no big deal.

With the fixture powered up and sitting face up on a pair of saw horses, it just didn't seem all that bright to me. From the boxes in the Big Box stores, each bulb should have 2700 lumens versus about 2100 from the old T12 bulbs. This is the first time I've used these 6500 K temperature bulbs (or any kind of T8 for that matter), so maybe the bluer light is throwing me a bit. Also I'm working by a double halogen work light (craftsman special), so maybe all that acrid white light is throwing off my evaluation. Does any of this sound like my lights are not working as they should? I guess my expectation from four of those daylight 6500K bulbs was to be hammered with light with the fixture pointing up at me from those saw horses. Were my expectations just off? I'll have a total of eight of these fixtures about 10 feet off the floor (32 bulbs total). Just wanted to try to be sure all was well before I got them all mounted.

Thanks!

[Peter Kelly]

I'm pretty leery of pretty much anything bought from HD/Lowes/etc. Try getting the same T8s from an electrical supply place and see what they look like in a side-by-side.

[David G Baker]

Jerome,
A lot of the new type bulbs take a while to reach full brightness. This could be why they don't seem as bright to you. All of the lights in my home are the screw-in type fluorescent bulbs with the higher color temperature. I find them so bright that they are irritating if they don't have a shade of some type over them.

[Jerome Hanby]

My bulbs did come from either Lowe's or HD, I bought a ten pack to have some bulbs to test with. I'll surf around for an electrical supply house. What is a good brand of bulb?

Also I'll fire that fixture up and let it run a few minutes. i only ran it a few minutes total while I was testing...

[Don Jarvie]

To really tell you need to get them on the ceiling. Just one set may not seem to bright but when you have all of them on you should notice a difference. I have 20 T8 bulbs in a 20x20 space and its very bright.

[Peter Kelly]

My bulbs did come from wither Lowe's or HD, I bought a ten pack to have some bulbs to test with. I'll surf around for an electrical supply house. What is a good brand of bulb?

Also I'll fire that fixture up and let it run a few minutes. i only ran it a few minutes total while I was testing...

I like Osram/Sylvania in a Cool White. Actually looks a bit warmer than the Daylight ones. Philips are fine too, just make certain to buy them from an electrical or janitorial supply place. So many items from the big box stores just aren't the same (plumbing fixtures are a good example of this) as what gets sold through the 'normal' distribution channels that people in the trades usually purchase from.

[ian maybury]

Hi Jerome. It may well be OK. I recently rewired my workshop and upgraded to a decent density of modern fluorescent battens with electronic starters.

I too was a bit sceptical at the seemingly low level of light when I hooked one up on the bench, but I have to say as Don that the light level produced by the finished job is great. It seems to be that they just don't produce the same in your face glare as a halogen or other high output incandescent bulb when seen close up. They start instantly, but as David it does take them a little while to get up to full brightness....

For reference my shop is 25 long x 20ft wide. There's five pairs of twin tube 1500mm battens placed end to end across the smaller dimension, with something just over 4ft (in the direction of the larger dimension) between the pairs. The whole grid is shifted a couple of feet to place a pair of battens end to end right over the bench. i.e. it's as a result more like 6ft from the last pair to the back wall/main doors/storage area.

ian

[Chris Parks]

The answer might lay elsewhere, how old are you? As we age our eyes require a LOT more light, I think up to three times the light to see as we did when younger. I am over 60 and my ceiling is a forest of lights and others say it is too bright but for me it is perfect. I made all my light fittings as unswitched power outlets to plug a small exetension cord into so if I need a new light I just put a double adaptor into the outlet, wire a fitting into the end of a short extension cord and add another light, best thing I ever did.

[Rod Sheridan]

Hi, due to reduced mercury content, the new T8 lamps will have low output for the first time they're turned on. Leave them on for an hour and check the light output.

After their first run in period they'll come up to full brightness instantly..............Regards, Rod.

[Matt Meiser]

The light is pretty weird color for a while too. The T8's I put in my finishing room probably took 30 minutes to really get going on the first run.

[Brian Tymchak]

I had the same thoughts when I was thinking through what I needed for lighting in my shop. (Hopefully I can get that project done this winter.) The flourescent puts off a lower intensity (lumens/sq in) light than say an incadescent. So it has to use more light emitting surface area to emit the same amount of light (lumens). You expected to get "hammered" with light from your fixture, but in reality, you are probably only getting about 25-50% of the intensity compared to a typical incadescent.

I rationalized the difference in the "intensity" of the light between flourescent and incadescent by this logic: A 4' 4x37w T8 bulb flourescent light is producing its 2700x4=10800 lumens from (roughly) 192 sq inches of light emitting area. A standard 75 watt lightbulb is producing ~1180 lumens from (roughly) 5 sq inches of light emitting area. Now, I know that using a flat surface area of round bulbs like this is not going to provide industry accepted measures, but it was a quick aid to help me accept what I was seeing.

[Jerome Hanby]

Thanks for the insight guys. What you are describing sounds exactly like what I'm seeing right down to pretty weird color. Since I only ran them a few minutes before I shut down for the evening, I bet after an hour of so of use they will be flying right.

[John McClanahan]

Like Matt said, new lamps take a while to reach full brightness. The 6500K color is a bit blue, even though it's called daylight. 5000K is more like daylight. Other lights, like work lights, will look less yellow when mixed with 5000K than 6500K.

John