Hi, I have just had a new pole building built. I had a 200 amp service installed. I will be installing 16 fluorescent light units. I will install them on at least 2, possibly 3 circuits. My question is what is the formula for figuring out the proper wire size, and how many of these conductors can I put in the conduit? I suspect if I use 3 circuits that 3 20 amp breakers will be OK, what size conduit would be required to run all the conductors, I think I am looking at 9 wires (hot nuetral and ground) total. Can I use the flourscent light as a raceway for wires going to another light circuit? The floursecnt lights are 8 feet long and have 2 110 watt 120v bulbs. Thanks for any help.
Cheers
Rob

Most of the cost is Labor, I would use 3/4". Depending on environment or conditions may determine EMT, Rigid conduit, PVC, and hate to say Romex, Could see future needs, exhaust fan, Hoist, AC,? Travellers for switching from multiple locations. Oh, and I would use #12.

There is no one convenient formula for this or any branch circuit installation, due the amount of variables. Sounds like you have a good plan so far.

Six 120 volt circuits in one conduit will need 7 wires, 3 hots, 3 neutrals, and 1 equipment ground.


A fixture needs to be rated and listed as a raceway to allow other branch circuits to pass through. This info will be in the specifications and/or instructions.

PVC conduit and fittings will probably be the easiest to install for a DIY'er.