Ok building a 42 x 35 garage.. 3 ten foot doors.. with 10 ft ceiling height over 2 bays and 15 feet on the 3rd bay.
was planning on switching the 3 bays on there own circuit..
ans was going for 4 8ft t8 double fixtures per stall running horizontal to the way u would drive into the garage spaced about 6 ft apart. so total 12 fixtures-24 8ft bulbs to light 42x35
Plus ant additional lighting for the over benches tool box and drill press on there own circuit.. so in your opinion will I need more lighting or will this be well enough lit..
There are several online lighting calculators you can use to determine such things as coverage patterns, brightness levels at working height, etc., for various different fixtures mounted at various different heights. I'm sure someone will be along shortly to post the URLs.
In the meantime, there are a few other points which might be worth considering:
First, I'm guessing that one high-ceiling bay is intended for a lift, at least eventually. In which case, any lights you mount more-or-less directly overhead will be mostly blocked whenever you have a car on the lift. Were it my shop, I'd probably try to use single- or twin-tube T-8 strip fixtures, mounted about 7-8 feet high on each sidewall (you'll probably have to go to about 10 feet on the side which is open to the rest of the shop, in order to have something to mount to). This will throw more of the light where it will actually do you some good, instead of simply lighting up the roof of that lifted car while you try to work in a huge shadow.
Much the same logic applies at least somewhat to the other two bays, as well; but obviously, the "shadowing" effect would not be as pronounced with the car on the ground.
I would also probably use 4-foot fixtures/tubes throughout, with no more than two tubes per fixture, in order to provide more flexibility in terms of both placement and switching. These will likely also be the cheapest to feed over the long haul, once you factor in bulb-replacement costs.
When figuring your lighting layout, count on breaking up each bay into at least two (maybe even three or four) separately switched "banks" of lights. This will allow you to deliberately go a little overboard on the total number of fixtures, so as to have really bright and effective lighting when desired (detail work, painting, etc. -- plus, our eyes are all getting older every day
), without being saddled with having to run all those lights when such bright illumination is not needed. This is also another argument in favor of the 4-foot tubes, as it helps you maintain relatively even illumination even when running only 1/2 or 1/3 of the lights.
Similarly, some minimal number of fixtures (probably one to three, total; but it will depend in part on the overall shop layout) should be considered your casual "walk through" lighting; and switches for these should be located anywhere and everywhere you might want to easily access them when entering or exiting the shop, even if that means three or four switches controlling that circuit. (Also, these particular switches should be
THE easiest ones to get to in any multi-switch bank, so they will tend to automagically fall to hand at such times.) The idea is, you don't want to turn on several hundred watts of light just to go fetch a screwdriver or somesuch. Assuming you also use this shop/garage for routine car parking, you MIGHT also want to rig these lights to be triggered by your garage door opener(s).
I gather that this is new construction. Given that, don't overlook the importance of the surface finishes on your floor, walls and ceiling. The smoother, lighter and brighter these surfaces are, the more efficient the lighting in that space will be, regardless of the number/type/placement of fixtures. And particularly with respect to the floor,
NOW is time to finish it in some manner which will prevent dirt, oil drips, tracked in road salt, etc., from making a mess of it almost as soon as you start to use it. [BTW... It's ALSO the time to consider installing PEX tubing in the slab (AND insulation under the slab) for radiant heating, even if you're not planning on installing any heat right now. It's relatively cheap to do this much of the job when the slab is first being poured; then just cap off the manifold and let it sit until the day comes you want (or can afford) to finish the job.]
my last garage was 20x20 and only had one 8ft t8. So it will be better than that. Just don't want to add more down the road..
I am a firm believer in "Do it right the first time."
