Flood Light Fixture Replacement

[Robert Higgins]

I want to replace some aging flood light fixtures on the outside of my home. I bought some motion-sensing flood light fixtures and went to swap them out, but I discovered that the electrical boxes are too small. The mounting screws in the boxes are spaced roughly 2-3/4" apart, whereas the screw holes in the cover plate for the new fixtures are ~3-1/2" apart. They are also oriented differently: the two holes in the box are in the lower left and upper right, whereas the holes in the fixture are in the lower right and upper left.

What are my options for attachiing these things? Is there some sort of adapter ring that will allow the new fixtures to attach to the old boxes? Is there a better solution?

Your kind advice is most appreciated.

[gfretwell]

You need flood lights with rectangular covers and you bought round covers.

[RBM]

It sounds like the existing box is a 3" round, or a 3" round extension cover on a 4" square box, and the new fixture is made to mount to a 4" round box only. Those are the only types of electrical boxes that orient their mounting screws on a diagonal. Most fixtures are designed to mount to a variety of boxes, so I would recommend returning the ones you got and replacing them with something a little more universal. Typical motion detector flood sets use a bar with a threaded hole in the center. The bar will screw to any standard electrical box, and the center screw holds the fixture canopy to the bar.

[hrhofmann]

There are adapter plates available in aomost any reasonable sized hardware store.

[RBM]

There are adapter plates available in aomost any reasonable sized hardware store.

I have never seen an adaptor plate that goes from a 3" box to a 4" box.

[Robert Higgins]

I searched on homedepot.com and couldn't find anything that looked like it would work.

I also searched there for a moti>It sounds like the existing box is a 3" round, or a 3" round extension

Unfortunately it's not that simple. These are Leviton units with built-in X-10 transmitters so that when one motion sensor is tripped all of the light fixtures come on, and they all stay on as long as any one of them senses motion. It's not likely I'll find a replacement with the same feature at any local store.

I would be happy to buy the bar and the matching cover plate and transfer the two lamp holders and the motion sensor over to it. Know any place that sells them? Worst case I could buy an entire cheapie fixture and just swap out the motion sensor unit, but that would be wasteful...

[gfretwell]

You need this one

[RBM]

That plate will only work if he has a gem box, but he describes the screws as being at a diagonal. Those are also a pia to use with motion detectors. There's just not enough space between the holes. I bought a universal cover , Rab CU4, from HD a few years ago, and I just used it on Friday. Damn thing was so sweet, I'm buying more on my next trip. I couldn't find it on the Depot website but here is a link to one:

[Robert Higgins]

You appear to have missed the part where I said the boxes are round.

[WW]

Did you read the specs at the prolight site? It says it fits round boxes. ww

[gfretwell]

I never saw you say you had a round box. If it is round and not the standard spacing, you have a round pull box, not a device box..

[hrhofmann]

There are adapter plates that look almost like coarse strainers, with threaded holes and slots that you can use to go to almost any size fixture with almost any size electrical box. I don;t know what their technical name is, but I have used them several times in owning 4 different houses of varying ages whan I wanted to change a fixture. You mount the adapter to the box using the slots to get the right orientation of the adapter, after putting mounting screws in whichever threaded holes will line up with the new fixture. Easiest thing in the world to do.

[Robert Higgins]

Even assuming the hole spacing is correct, it would leave the rectangular plate at a 45 degree angle WRT the ground. Not the most aesthetically pleasing solution.

[Robert Higgins]

Whatever that means.

All I know is the original fixtures (which may be original to the house) fit the current boxes just fine, but the replacement fixtures I bought are too big.

I looked for the adapter rings mentioned in another post and couldn't find them, so I settled for this:

As another poster mentioned, this unit has the universal strap thing that fits the holes in the exiting box and has a center hole to which the fixture itself attaches. I swapped out the motion sensor unit from the larger fixture and ended up with a combination that fits perfectly. Plus the white color matches the fascia. At $25/fixture this is an expensive solution, but at least it works.

In the meantime, I'll keep looking for those adapter rings. Is there an official name for these things that I can search on? Various combinations of "electrical box adapter ring" turned up nothing useful.