> I only use metal electrical boxes.
There's nothing wrong with metal boxes. I've used them in many situations
like ceiling fan mounts where I need the strength, or specific shallow
boxes I couldn't find in plastic.
> metal provides a good ground
Metal boxes require a grounding pigtail wire, which is an additional
cost. It can also reduce the box fill in certain situations.
The cable clamp in metal boxes usually takes up a bit of space, further
reducing the box capacity. In some cases, a cable clamp has to be
installed separately (like my ceiling fan boxes).
As you mentioned, metal boxes rust. I had to replace several outlets at
my in-laws house and the fixture screws were rusted to the boxes. It took
some work to get them out. The screw heads stripped out so I had to use
vice grips to unscrew them.
> Then comes the issue of those platic boxes breaking inside a wall.
> Granted, under normal use they should not break, but given a little
> too much pressure, they shatter easily. Which of course means
> ripping a wall apart,
The blue boxes made by Carlon are nearly indestructable. I've literally
beaten the things with hammers and prybars when I've wanted to change a
mounting location. They've deformed on occasion, but I've never cracked
one.
Even so, if the box cracked inside the wall, or the mounting screw
stripped out, you could use a reciprocating saw (or small hacksaw blade)
to cut the nails that attach the box to the wall. Then the box will slip
right out. Minimal, if any, damage to the finished wall.
> those blue plastic boxes are a real pain in the butt to get the screws
> into them. Apparently they are not pre-threaded.
I usually use my cordless drill to drive the screws in most of the way,
then use a screwdriver for the final turn or two to secure the outlet (so
I don't strip the hole driving the screw all the way with the drill).
> This garage was over wired, meaning that it literally had an outlet
> every 4 feet, on all walls, and had two rows of lights spaced 3 feet
> apart across the entire ceiling. To me that seems excessive.
I wired my garage with outlets every four feet also. I do a lot of
woodworking and many times wish I had more outlets along a wall. I have
some things that stay plugged in all the time (battery charger, radio,
dust collector, etc.) so those outlets are used up. A few other's are
behind carts or tool boxes where they're difficult to reach.
If I had it to do over, I'd probably install an outlet every 32" (every
other stud bay). I've thought about replacing all the single outlets
with double-gang outlets (four sockets each box), but haven't been that
motivated. :)
I usually just run an extension cord from one of the other walls. It
usually works out best anyway since each I wired each side of my garage
on a different circuit. It lets me use two tools at once without tripping
the circuit breaker.
I installed two circuits for outlets in the garage. I would probably run
additional circuits if I had it to do over.
> one of the most common problems I've noted with them is that
> they will crack where the screw goes
I've never had a box crack at the screw hole, even when I've stripped the
hole and installed a larger screw. Are you using the screws that come
with the outlets/switches? If you're using a tapered screw of some kind,
it might be acting like a wedge forcing the box apart.
> that means ripping walls apart to replace them
As mentioned above, you can remove the boxes without damaging the wall.
However, if it's just a stripped screw hole, you could probably fill the
hole with epoxy. Let it set up, drill a new hole, and install your new
outlet.
> For fifty cents to a dollar more, I'll spend the extra cents
> and get a reliable and durable metal box
The price difference is no big deal if you're only talking a few boxes.
If you're wiring an entire room or building, that can be a significant
difference in cost. Especially since you need to buy grounding pigtails,
and maybe cable clamps too.
> I dont know if they make a better quality plastic box, but I'm not at
> all impressed by those cheap blue ones.
They do make better plastic boxes. I'm not sure what they're made of,
probably bakelite or fiberglass. But, they cost more and usually have
fewer size choices. I've used them on occasion when I couldn't find the
blue box I needed, but they're not my first choice.
Most of the time I use the blue boxes based on price and maximum fill
capacity. But I don't hesititate to use metal or the fiberglass boxes to
accomplish what I need. Basically, I use whatever box does the job at
the lowest cost.
Anthony Watson
www.mountainsoftware.com
www.watsondiy.com