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How many

Posted by sjt2900 (My Page) on
Thu, Sep 16, 10 at 20:30

We're building a pole pole barn 30' x 64'. The trusses are 8' apart. We're planning on using those 200 watt curly fluorescent bulbs. My cousin used these in his 50 x 64 barn and the lighting was great. Our question is how many lights across should we use on each truss? 3 or 2? Or do you have a better idea of what lighting to use?

Follow-Up Postings:

RE: How many

I assume when you say "200 watt curly fluorescent bulbs" you mean CFs which claim to be equivalent to 200 watt incandescents. Those would be about 50 watts or so, pretty big for a CF.

FWIW, I've seen actual 200 watt CFs offered, but they're not very compact, nor are they very cheap, and they have mogul (extra large) bases. But they sure do pump out the lumens - 11,600 of them. (See link below.)

It really depends on how much light you want or need for what you plan to do in the barn. Don't forget that with no white ceiling to reflect the light, you'll need more lumen output than you would in a normal household room.

Our barn houses animals and I installed decent quality damp area linear fluorescent fixtures with two 32-watt lamps each. One is in the center, and one is over each of the two animal stalls, all separately switched. It's plenty of light for our needs.

I fitted protective polycarbonate tubes over the lamps just for safety, even though the lamps are WAY out of animal reach.

Here is a link that might be useful: Maxlite 200 watt compact fluorescent

RE: How many

davidr--Thanks so much for responding. The bulbs are Sylvania screw base twist bulbs from Menards and the package says "200 watts replacement using only 65 watts." The price is under $20. The barn will be wired so we can turn on only one section at a time if we want to. What we're wondering now is since our barn is about half the width of cousins should we use 100 watt replacements instead of 200 and put 3 lights across each truss. We like these bulbs better than the tube lights because we've had the tubes before and had so many problems with ballasts. The barn has a 14' ceiling and it would be a pain to have to get up there all the time. So, we thought we'd use plain old porcelain fixtures and these bulbs because they are supposed to last for a long time. Does that make sense?

RE: How many

FWIW, I started out with incandescents in our barn, changed to retrofit CFs, and finally went to linear fluorescents. We are much happier with the linear lights. They give a better light distribution. With fewer shadows and a larger area covered, doing barn chores is easier.

I really don't recommend retrofit CFs for this application. Most retrofits typically last about one-third to one-half the total hours of linear fluorescent lamps (6,000-10,000 vs 20,000-30,000). Their ballasts are smaller and less robust, designed to be chucked out along with the lamps when the lamps fail. The ballasts are in the base, so base-up mounting (which you'll probably be using) shortens the lives of retrofit CFs even further from the rising heat.

Let's look at the Sylvania retrofit CFs you're considering against a 2-lamp linear fixture using an electronic ballast and two F32T8 lamps. The CFs use 65 watts vs. the linear fixture's 64 watts, almost exactly the same.

LIFETIME: The Sylvania CF is rated for an average life of 8,000 hours. Linear T8 lamps have an average life of 20,000 to 30,000 hours - about 3 times as long. The ballast is located farther away from the heat of the lamps and is (or should be!) much more robustly designed, so it should last for 10-20 years of use.

EFFICIENCY: The Sylvania CF produces 4200 lumens. A typical linear fixture with electronic ballast and two F32T8 lamps, using the same number of watts as the CF, produces 5900 to 6200 lumens - at least 40% more light for the same energy.

Now, I'll grant you, the linear fixture will probably cost more than $20. But remember, the lamps themselves will last a good 3 times as long - and when it's time to replace them it will cost you about $6-8, not $20.

If you've had ballast problems, it might be that you've had poor quality fixtures. I've opened up some of the cheap big-box-store shoplights. The ballast inside of recent ones is often not much better than the vastly simplified and shrunken ones used in retrofit CFs.

One of the strategies I've used several times is to buy those inexpensive fluorescent fixtures - and replace the crummy ballasts before I even plug them in, using commercial quality electronic ballasts. But that might be a little more "geeky" than what most folks here would want to do. :)

RE: How many

Wow! You"ve really given us a lot to think about. The barn
walls should be finished tomorrow. DH is in the process of running conduit from the house to the barn that will carry wires for lighting, cable tv, telephone and intenet. This is his dream and we're researching everything we can. Thanks so much for sharing your wisdom. I will definetly passalong your suggestions!

RE: How many

He probably knows this, but be sure you use separate conduit for low voltage and line voltage services. Don't mix them in the same pipe.

I'm pretty sure you can have the phone, television, and internet lines all in one conduit - someone correct me if that's wrong - but the electrical lines should be in a separate one. This isn't just a matter of code or safety, it's practicality; induced electrical fields can play hob with those other services.

Best of luck with your project!

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