Theatre Design & Technology - Summer 2013 - 24

QUICK REFERENCE CARD: NEC FREQUENTLY ASKED QUESTIONS
WHERE DOES IT SAY...?
...that I can't use lamp
cord to power stage equipment?
...the exceptions to using
extra-hard usage cords?

Article 520.68(A)(1): "Flexible conductors, including cable extensions, used to supply
portable stage equipment shall be listed extra-hard usage cords or cables.
Article 520.68(A)(4): "Listed hard-usage (junior hard service) cords shall be
permitted in breakout assemblies where all of the following conditions are met: ..."
And 520.69(C): "Conductors for adapters and two-fers shall be listed, extra-hard usage
or listed, hard usage (junior hard service) cord. Hard usage (junior hard service)
cord shall be restricted in overall length to 1.0m (3.3ft)."
...when my equipment has to
Article 250.4(5) "Electrical equipment and wiring and other electrically conductive
be grounded?
material likely to become energized shall be installed in a manner that creates a lowimpedance circuit facilitating the operation of the overcurrent device..."
And 520.81: The metal frames and enclosures of all equipment, including border lights
and portable luminaires, shall be connected to an equipment grounding conductor."
...wiring and cabling has to be Article 520.69: "Each receptacle and its corresponding cable shall have the same
rated for the OPD instead
current and voltage rating as the plug supplying it. It shall not be utilized in a stage
of the load?
circuit with a greater current rating."
...required cable gauge relative Article520, Table 520.44It says: 15A=14AWG and 20A=12AWG, so you cannot use less
to overcurrent device?
than 12AWG cable on a 20A circuit.
...I have to use equipment
Article 110.13(A)(8)(B): "Listed or labeled equipment shall be installed and used in
according to what is made for? accordance with any instructions included in the listing or labeling."
...cable use and labeling?
Article 400, Table 400.4. Also check the manufacturer specifications because
110.13(A)(8)(B) (above) requires that you use equipment according to instructions
included in the listing or labeling.

LEDs you can put on a 20A circuit, just divide
20A by 1.15A to get 17.54. Then, confidently
load the circuit with up to seventeen LEDs.

We are trying to do art here!
NEC section 90.1(B) says, "This Code provides provisions that are considered necessary
for safety. Compliance therewith and proper
maintenance results in an installation that is
essentially free from hazard but not necessarily efficient, convenient, or adequate for good
service or future expansion of electrical service" (22). Probably the fastest way to loose
the confidence of your AHJ is to suggest that

22

theatre design

& technology

the rules should be bent for artists. It is easy to
argue that educational and arts institutions are
poorly funded, and that our work is inherently
different from manufacturing, but the NEC and
the AHJ responsible for enforcing it are only
concerned with safety. There is no excuse for
putting people in danger.
Some of the rules that pertain specifically
to theatre, like having to use thicker, more expensive extension cables, were developed by
professionals whose job was to evaluate risk
in the context of specific applications. For instance, Article 520 takes into consideration
the fact that theatre people need to be able to

s u m m e r 2013

move stage equipment to a new location for every show. The rules also take into account that
we move fast and we are not always given the
time or the resources to inspect or maintain
things to the standard that some other industries might be able to do. There are few workplaces like ours where cables get run over with
personnel lifts, wrapped around sharp corners, taped under mats, and hooked around
automated platforms and moving pipes. Take
a look at the safety label on a typical hardware
store extension cord. It probably says "DO
NOT USE WHEN WET" and "Do Not Cover It
With Any Material," and Do Not Drive, Drag,
Table of Contents for the Digital Edition of Theatre Design & Technology - Summer 2013
