Boxes on house for outside lights

Can I get opinions for the installation of boxes for electrical service for outside lights? I'm putting on fiber cement board lap siding and I don't know how to position the boxes. Should I use round boxes or square boxes? My builder said to use just a plain square zip box to hold the wires and then screw the light fixture into the fiber cement board lap siding. I don't want to do that. I want to use light fixtures with a round connection to a round box with a gasket. But, I'm not sure as to how far to stick the box out. The lap siding is not yet installed.

I'm concerned about the vertical position of the boxes. Should they be contain on one whole piece of lap siding or should I split them over two pieces of lap siding and then use a thick gasket. Should I wait until the lap siding is installed and then put the box up. I think my neighbor waited until the lap siding was already up and then used a 4" circular saw bit.

Another option is to get a block of the edge board (the one that does vertically at the corners of the house) and put the round box through that so that there is a flat piece to stick the light fixture to.

Thanks

 

I think it is easier to split on a seam between two pieces of siding.

Go to www.aifittings.com and look at the siding boxes that are available.

 

Use round or octagon boxes. NEC permits square boxes to support fixtures to a certain weight using 6-32 screws, but round boxes use 8-32 screws. That will give you more flexibility in fixtures.

Easiest if you will have access from the back after siding is installed. How far to stick it out depends on the thickness of the lap. You'll have to figure that out. Although a plastic depth ring and longer screws will solve most problems.

Presumably you already have your light fixtures selected so you can mount your boxes so the finished fixture is at an acceptable height. That will determine roughly where to mount them. It's easier to mount them in one piece of siding. Some fixtures go up from the box, some hang down, some are level. It makes a huge difference.

Take a good scrap of siding of suitable size, turn it upside down and position so its front is approximately vertical, cut to fit around the box, and secure. That provides a plumb mounting surface for your gasket and trim.