How can/should I mount this porch light?

Question

I want to mount a porch light on my outdoor shed/office. I recently had an electrician place interior wiring however I elected to do the fixtures myself.

Uh oh.

Here's what the back of the porch light area looks like (on the inside of the shed):

Here's what the front looks like:

Here's a picture of the light I want to put on the outside:

The wall is a solid piece of wood about 1.5 inches thick so I don't think there's room to add a fixture bracket.

So... I'm stumped. How should I attach the light?

Answer 1

A pretty common approach is to build a small platform for the lamp to sit on, something like this

This has the advantage of giving you more depth to mount a receptacle box. You can use 3/4 inch material (nominally 1x ) or larger, such as 5/4 stock. You can then cut a hole, using a hole saw through the new block and the siding underneath giving you enough depth for a much deeper box, like this one

It also has the advantage of making it easier to get the base of the lamp vertical.

After the box is set, I would caulk the entry point of the wire and around the box itself. After the lamp is mounted, unless the fixture has its own gasket, caulk around the top, sides and all but a small section of the bottom (a weep hole just incase any moisture gets in.)

Answer 2

I would opt to use a 1/2 pancake box 4" in diameter. The NEC code does not permit the canopy or empty space of a fixture to substitute for cubic wire space for wires larger than #16 gauge. And a 4" pancake boxes cubic space legally can only hold one 14/2.

Since you already have the wire conduit on the inside of the house I would also consider using something like this box to mount the fixture to.

After reading a lot of the great comments I wanted to update my answer with some new advice.

Because a 4" pancake box is limited on the cubic depth you would need a round extension. 1/2" will add an additional 3.3 cubic inches. A 3/4 extension would add an additional 5.0 cubic inches One 12/2 would require 6.75 cubic inches so a 1/2" extension would suffice.

Installing the pancake box and the 1/2" plaster ring would require 1" of depth so that leaves you only 1/2" of wood to mount the box to. Using three or four weather rated 1/4" wood screws would secure the box without penetrating the interior side.

As a side thought maybe you could only recessed the pancake box 1/2" and leave the plaster ring concealed behind the light box. From the picture it appears to have enough room to conceal the extension ring.

Keep in mind you will probably need to rotate the box so the mounting bracket that comes with the light will not interfere with the box or the extension rings screw holes.

Answer 3

Not sure if it's the "approved" method, but I've seen it quite a few times (mostly for fixtures on the front of a garage). The fixture wires are fed through the hole into the box inside, where the electrical connections are made by approved means. Then the fixture is simply mounted directly to the wall, typically with a gasket between the fixture base and the wall (should be included with the fixture).

You might use a bit of duct seal or similar, to seal the hole where the wires pass through. The gasket should keep weather out, but the duct seal will help keep the bugs out.

The "proper" method, with a normal wall, is to build an appropriately sized box into the wall.

Then weather seal the fixture to the box.

Answer 4

None of the answers given will make that fixture sit flush. It’s your house correct mount the mounting bracket right to the wall use the fixture housings as your box caulk around and have a nice day. It will be fine for 50 yrs make good connections tape them up use a 9watt LED build and have a nice day. Sometimes the code goes a little to far the fixture will look great and zero heat will emit with a 9 watt bulb. Sometimes you simply need to get the job done stop thinking so much.