I am trying to get opinions on the most efficient way to install 25 high bay light fixtures. I am bidding this new facility, it will be a steel building with z purlins. I have limited knowledge of electrical installation practices in this scenario. It is an open shell of a building with the max height at 26' in the center and 12' at top plate. The fixtures have the option of being hung with jack chain, aircraft cable or stem. There are 5 fixtures per row and 5 rows. Every fixture will have the same length of cable etc. as the fixtures gradiate in height as the ceiling height changes. My idea was to mount 20' of strut across the I beams in a line above each row of fixtures and mount the j box and conduit to the strut and the cables strung around the strut. I was hoping to get input on perhaps a better way of hanging these.. I thought about using the z purlins but eventhough they are spaced every 4', there is no garuntee they will line up with my rows of fixtures. I have looked through the cooper b- line catalogs and found clamps etc. but... this seems a very common type of building, (that i don't have experience with) and thought maybe some one can give me pointers on engineering an electrical installation of this type. Thanks
a butler building, it's often called.
http://www.erico.com/products/SpeedLink.asp
those work well for hanging stuff. they aren't cheap, but they are fast.
most of the time, they want the lights level, so you throw a laser on
a post somewhere, and set lights with that. a scissor lift where you set the
height and then go around and trim them all at once works if you don't
have a laser handy.
the caddy cables are quick, and easily adjusted.
for a butler building, the purlins usually are prepunched
with 1/2" holes to be adjustable, and what i've done is to
punch those holes out with a greenlee knockout, to run
my conduit thru. makes for a clean fast install.
condulets, and bx down to the fixtures, ty wrapped finishes
it up. i don't have to support condulets. if i'm opening holes
thru the z beams using pre punched holes, it goes fast,
and i just extend the run thru the next beam to support
the T condulet. if the holes don't work in your favor,
one hole straps to the bottom of the z metal usually does.
i tend to avoid j boxes cause they aren't self supporting.
so, you are looking at 30 condulets, some emt, some
wire, 25 caddy cables, and the fixtures. it goes up fast,
if you have unobstructed floor to drive a lift around on.
if you have to span the z metal, and can't shift the lights a bit?
if the z metal is 4' on center, your maximum deviation
would be 2' off a centerline, and most buildings can tolerate
that.
