Surface-mount junction box for exterior light
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I want to mount an exterior light without cutting a big hole in my SmartSide panel siding, just a small hole for the wires. Attached is a photo of the base of my light; the outer diameter of the base is 5-1/2″. The little black rectangular box inside the base would seem to prevent it from fitting over anything’s protruding edge. Is the only option for a junction box that sits on the surface of my siding, instead of recessed into the wall where it would displace insulation, something like the Arlington Wall Plate, photo also attached? If so, is the Arlington product the best choice of its type?
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Replies
That little black box looks like an “electric eye”, a device to automatically turn the light on when it gets dark outside. If you don’t want that feature, you can just remove that device and plug the hole in the light. You can also remote mount the electric eye somewhere else — it doesn’t have to be in the light fixture itself to be able to function. You can mount the electric eye in another electric box, it just needs weather protection (although there are other styles that don’t, and those will get easier to remote mount).
Another option for you is to cut a piece of wood or pvc trim board to make a base for your light that is thick enough for you to conceal a regular electric box inside. I’ve done that before myself. Just be sure to seal the top of such a custom piece to the wall so that water can’t sneak in behind the piece.
Bill
Here's what we did. Boral (?) mounting block fit to the the clap height extends through the claps and air gap to the WRB/sheathing, flashed on top, Kaplex gasket (https://foursevenfive.com/kaflex-mono-wire-gasket/) behind the block (adhered to the WRB) to provide the water, air seal around the wire. Wire is still able to move in and out a bit when fiddling with the fixture mounting. mount whatever junction box you need on the block.
I like the box to be mounted on something vertical, so I'll either put a piece of upside-down siding or a piece of trim cut on a bevel to create a vertical surface. Between the block and the siding and between the junction box and the block I'll put an upside-down U of sealant so the top is sealed but it can drain to the bottom. Between the block and the siding I'll put z-flashing like Wooba Gooba shows. The actual penetration is filled with sealant. The cable goes out through a hole in the back of the junction box. The exit to the box can either be a short piece of 1/2" PVC conduit or a clamp.
Thank you, Bill. I hadn't thought of putting a regular box inside a block of wood.
Thank you also, WG and DC. My SmartSide is of the panel type, but I'm sure others reading this will be find your tips for lap siding quite helpful.