Electrical Contractor

I S T O C K / A L E X A N D R D U B O V I T S K I Y

That’s good to know, right? After all, tunable color is available using off-the-shelf LED systems. Color temperature is way beyond most homeowners’ sophistication, but I typically mention the issue to them.

Picking luminaires for a home is a tricky challenge. Most commonly, my customers will select fixtures from a showroom—or, nowadays, a printed or online catalog—without any input from me. If they contact me before they go to choose a luminaire, I have two priorities. First, I need to emphasize that the listing cannot require outlet wiring to have a higher rating than their house offers, so I don’t have to pull a permit to install a new outlet with modern 90°C wiring. It can be dicey when we have to tell customers things that upset them.

Second, I usually say, “Tell the sales-
person you need a fixture designed to go
against a ceiling, under an electrical box.
If you might want a different kind of fix-
ture, we need to talk about it now.”
Warning or no warning, it’s easy for
customers to make mistakes in luminaire
choice. Sometimes it’s the “no chocolate”
rule. When you’re busy, it’s hard to keep
in mind a negative or an instruction not to
do something. If you try to improve your
diet by not eating chocolate, you might
remind yourself “no chocolate,” but the
dominant message here is “chocolate.”
There are some tricky bits to the
requirement, too. Recently, an intelli-
gent customer listened carefully to my
warning about temperature ratings. I had
noticed an existing luminaire showed
intermittency, and it didn’t seem to be
associated with a loose lamp. I suggested
that he might want to consider replacing
it but his wiring forbade a fixture speci-
fying 90°C conductors. The customer
asked me about LED fixtures: “They
don’t get hot, do they?” I acknowledged
that LEDs use a great deal less power
than incandescents and throw less heat
into the room. While you would expect
wiring near LEDs to stay cooler than wir-
ing near incandescents, it’s not as simple
as it might seem.

A few days later, the customer showed up with two listed, linear LED luminaires—to light a different space, his utility room, which had an unfinished ceiling and a single porcelain lamp holder.

In this case, I didn’t have occasion to concern myself with the type of ceiling they were designed for. When we opened a carton, we found the 90°C label on the luminaire. It had not been present on the carton.

This brought up two issues: intended location and suitable wiring.

Having a roughly 3-inch knockout,
but lacking ½-inchers, the new lumi-
naires appeared to be designed solely for
mounting under boxes, normally against
finished ceilings. This is not so terrible;
after all, smoke alarms are also designed
to be mounted the same way. Despite
this, everywhere I work, the inspectors
accept smoke alarm installation under
boxes mounted to open joists. The key
may be that they don’t rely on a ceiling
surface to serve as part of the enclosure.
By contrast, flush-style device covers are
not listed for use on surface-mounted
utility boxes. The slight convexity of
most of these plates is designed to ensure
good contact with the wall surface that
boxes are mounted inside of.

Now for the old wiring. Installing a 90°C-rated luminaire will mean I fish to a new box near where they have their light, leaving a blanked-off outlet.

If they’re fairly lucky, I can flip the present wiring into a nonhabitable but accessible attic and bring new wiring into the current box or to a new box in the same location.

If they’re very lucky, despite having a somewhat older home, their ceiling-lighting outlet was wired or rewired at some point after 1984 (that is, after the nonmetallic cable manufactured before the 1984 standard change was no longer around), so the conductors are rated for 90°C. Or if it’s an even older house, they’re lucky if they have conduit through which I can pull new conductors. (Beware of repurposed gas pipe in this case.)

Why am I writing about an older house? Most of the houses I work on are definitely not new, though some of the new ones have issues of their own.

There’s one more common possibility, and then there’s the brand-new situation I encountered on this job. I’ll describe it next month.

The Right Match
Picking fixtures and feeding modern lights

LAST MONTH, I WROTE ABOUT THE IMPORTANCE of having sufficient lighting and the benefit of seeing by different-colored light over the course of the day. That latter issue is big. Staring at a bluish computer screen at night tells parts of the eyes and brain that it’s time to wake up. Reading by a light-emitting diode (LED) light with a 5,000-kelvin (cool white) color temperature does the same thing.

RESIDENTIAL BY DAVID SHAPIRO
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.