RESIDENTIAL BY DAVID SHAPIRO
A bathroom fixture brought this to
mind. It was a combination exhaust fan/
room light/night light. Anybody in residential wiring would recognize the major,
reputable fan manufacturer; just about
anyone in this country would recognize
the listing laboratory. The instructions
were pretty clear. They weren’t the sort
of garble that seems likely to have been
written by an undertrained and underpaid worker in a developing country and
translated into English by cheap software. All the same, the instructions didn’t
necessarily fit the situation in which the
fan was going to be installed.
If this makes you wonder why I was
even dealing with the fixture, the answer
is simple. My customer had chosen it, and
I was in the position of deciding whether
to reject it outright or to decide that it
was acceptable. It barely squeaked by.
Some of this was a matter of the instructions, some of it the design.
The first piece is easy to explain,
though it can get interesting. The
instructions said to run a three-wire and
a two-wire cable from the switch box
to the splice compartment. One of its
loads needed to have its own switched
conductor and its own separate neutral.
I figure this was because the manufacturer didn’t want current coming in on
one switched conductor and returning
on the other neutral or dividing between
two neutrals. This is clear electrical
However, there are other ways to
toast that bagel. It happens that I often
carry some 12/4 cable with me. It’s good
for running three-way switches and car-
rying a neutral with me no matter the
layout. The 2011 NEC requires this. It
also would be good for carrying three
switched conductors and a neutral from
this bathroom’s switch box to the fixture.
No need for two cables.
Would it be in keeping with the product’s listing? I suspect so but not with
instructions. How about bringing power
first to the fixture and then running
power down and three switch legs back
sans neutrals? Same issue, same answer.
Could the extra conductor make the wiring compartment crowded? We’d have
two conductors with power and four
going down to the switch box, as compared with two and three coming from
the switch box. So maybe it would be
crowded. However, if we happened to
run BX (Type AC cable) in this scenario,
we’d have one less wire in the wiring
compartment than should we run MC
or Romex (type NM) strictly per instructions. I just ran 12/2 and 12/3 MC.
What gave me pause on this job was
something different. The cover for this
fan’s wiring compartment was above it
on the attic side. The instructions spoke
of securing the fan to the joists, attaching
cables and making splices from above.
Maybe this was different from what I
usually see, but so what? In this case, the
attic above was not even a crawlspace.
Once the fan was secured, it would be
inaccessible except by opening the ceil-
ing or at least cutting it open enough to
drop the fan. The applicable Apollo 13
phrase was, “Houston, we have a prob-
lem.” This was not a light-emitting diode
(LED) luminaire mounted over a sepa-
rate concealed outlet box, where NEC
410.24 (B) might require access. Even so,
I always want to retain permanent access
to splices without the need to damage
There was an out. By undoing the
screws holding the fan motor to the fixture body, we could gain access to the
wiring compartment from below. There
was nothing about this in the instructions. Still, I was satisfied. Were we
following the instructions? Nope. The
fixture was suspended from tie wires
using the adjustable mounting grid while
it was wired. Then the cover went on the
wiring compartment, and the flexible
duct from the roof vent was attached to
the fixture. Only then was its mounting
grid pushed up and screwed to the joists.
The manufacturer’s assumption, it
would seem from the instructions, was
that this fan would be installed where
there was access—possibly permanent—
from above. However, neither the package,
the fan, nor the instructions specified for
installation where there is (permanent)
access from above.
Wouldn’t it be nice if listed products
came with instructions that specified
what was demanded for compliance with
listing requirements? That would separate this out from, “Now here’s how you
might install this.”
Listing requirements versus instructions
I HAVE A LOT OF RESPECT FOR A LISTING MARK. It means, first, that the
design of the device I’m going to install was tested and complies with safety standards. Second, it implies follow-up, ensuring that this piece I’m putting in complies.
I have a lot less respect for installation instructions. They should tell me, at a minimum, just what I must and mustn’t do if I want the product to work, and the listing
investigation should cover where I install it. Unfortunately, this can get murky.
SHAPIRO, 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. S H