RESIDENTIAL BY DAVID SHAPIRO
What was left to try? Maybe the
protective device itself is defective. I
disconnected the home run from the protective device and tried it. Nope; it stayed
on happily. The reset and test buttons
worked fine with the cable disconnected.
Back to the bathroom to trace each
wire. I noticed one extra cable leaving
the outlet beside the one going home
and the other going to the switch box.
Where’s the blank outlet I had installed
for future use? Missing. I punched out
the wall, freed the pigtails that the drywallers had trapped together because
they didn’t have wirenuts, and got an all-clear from the protective devices. This
took a good bit of box extension before
I could cover it and be done.
This was a new one to me. I knew
the drywallers had been very sloppy. I
talked this over later with my good friend
Larry, and he told me that I wasn’t the
first to experience this sort of nonsense.
He learned to mark the floor in front of
every box he roughed in, so that if—not
when—a drywaller covered a box, Larry
knew pretty well where to open the wall
to uncover it.
Here’s something else Larry discovered on at least one job. The drywallers
hadn’t precut his box openings. Instead,
they found his boxes and ran a blade
inside them—not outside—guided by
the box’s walls. They didn’t seem to care
about the wires. For Larry, this meant
After hearing about that, I didn’t feel
so aghast that the painter got paint on my
The residue he left in boxes’ device’s
mounting screw holes was a bit more
annoying. Where I planned to use self-
grounding devices, could I rely on the
6-32 screws to clear the paint out of their
way? With locknuts, cutting through a
little paint may or may not be part of the
design. Mounting screws? I don’t think
cutting an adequately conductive path is
expected. I went through every clogged
screw hole with a 6-32 tap. In retrospect,
it would have been almost as fast—and
a better job—to run bonding wires from
the devices’ green ground screws to the
boxes’ 10-32 holes.
Maybe I’m a bit of a fussbudget to
concern myself with this, but I didn’t
come up with it out of the blue. I read
a lot of the trade press and background
material, and I attend many continuing education workshops. The safety
research eventually got through to me.
I recently have become a lot more
fervent about torquing screws, instead of
saying, “I’ve been doing this for 40-plus
years; I know how to tighten properly.”
That being said, there’s a pricey new
line of residential devices that don’t
include this. The installation instruc-
tions say to “Insert wires into terminals
and tighten screws securely.” Torque?
Nope. Maybe using a torque screw-
driver on their Phillips setscrew makes
it cam out? I emailed the manufacturer
for torque ratings and got no response.
Fortunately, I noticed that National
Electrical Code Annex I, Recommended
Tightening Torques, pulls values straight
from the UL Standard, 486-A-B. Unfor-
tunately, Annex I only talks about slot,
hex, recessed Allen, and square drives,
The device gave me one more surprise. The package warned that the
receptacle needs a box with at least 22
cubic inches. Once you take it out of the
box and read the instruction sheet, you
find that it also requires a minimum
depth: if the box contains a single circuit,
then it’s 3 inches for a plastic box and
3. 5 inches for metal. Because they real-ize your box may not be the depth they
require, they list the boxes they approve
for replacing your box. So, as far as I can
tell, none is legal for use with metal-sheathed cable MC or BX. Whoops! Now
that list is an example of an instruction
that is not a listing requirement.
Not the Only Ones Involved
Dealing with issues caused by others
UH OH, ANOTHER TROUBLESHOOTING HASSLE! This time, it was a brand-new, two-wire bathroom circuit that tripped the arc-fault circuit interrupter and the
ground-fault circuit interrupter feeding it. First, I disconnected all of the switches
feeding the light, heat lamp and exhaust fan. Trip! Then I disconnected the two
receptacles in the adjacent box and tried again. Another trip!
SHAP IRO, author of “Old Electrical Wiring: Evaluating, Repairing, and Upgrading Dated
Systems,” is a contractor, consultant, inspector and writer/editor based in Colmar Manor, Md.
He also is affiliated with IAEI. He can be reached at firstname.lastname@example.org. IST