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.
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.
On Sun, 10 Oct 2010 19:21:09 -0700 (PDT), in alt.home.repair "hr(bob)
I searched on homedepot.com and couldn't find anything that looked
like it would work.
I also searched there for a motion-sensing flood light cover plate
that would fit the smaller box, but they all seemed to be the large
size like I already have.
On Sun, 10 Oct 2010 22:11:18 -0400, in alt.home.repair "RBM"
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
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:
On Mon, 11 Oct 2010 12:31:23 -0400, in alt.home.repair
Whatever that means. <shrug>
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
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.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.