There’s a new sheriff in town,” is
a common saying in cowboy
movies of the 1960’s and it applies
to electrical safety today.
In 1994 OSHA promulgated 29 CFR
1910.269 covering utilities with what became
known as the “apparel standard”.
This standard required utilities to wear
clothing which would not “increase the
extent of the injury” in electric arc exposures.
It continued the use of cover up
barriers, rubber gloves and hot sticks for
utility line workers but didn’t really have
much of an effect on electricians. The
OSHA language in the hazard assessment
standard requiring companies to prevent
or protect from “arc flash” had little effect
since there were no standard guidelines
on “how” to do that.
In 2000, a “new sheriff” entered the
scene for electricians doing non-utility
work, NFPA 70E, Standard for Electrical
Safety in the Workplace. NFPA 70E
however excluded many operations
specifically, utilities, communications,
railways and mining. Though some operations
in those companies are covered
by NFPA 70E, such as building maintenance
electricians, many are excluded.
This gap in the coverage and the vagueness
of the OSHA utility standard left the
need for more clarification for utility type
work. This is now being filled by the
NESC 2007 version. The NESC, National
Electrical Safety Code, has included
a work rules section in this public safety
document for several editions. It now has
an arc flash section which will change the
way utilities look at arc flash protection
but this doesn’t ONLY cover utilities. It
covers all contractors who work on transmission,
generation and distribution of
electricity in a utility type application.
The NESC begins for utilities what OSHA
began and NFPA 70E continued for electricians
of all sorts. It now requires PPE
to protect from the hazard.
NFPA 70E does not cover the following:
(1) Installations in ships, watercraft other
than floating buildings, railway
rolling stock, aircraft, or automotive
vehicles other than mobile homes and
recreational vehicles
(2) Installations underground in mines
and self-propelled mobile surface
mining machinery and its attendant
electrical trailing cable
(3) Installations of railways for generation,
transformation, transmission, or
distribution of power used exclusively
for operation of rolling stock or installations
used exclusively for signaling
and communications purposes
(4) Installations of communications
equipment under the exclusive control
of communications utilities located
outdoors or in building spaces
used exclusively for such installations
(5) Installations under the exclusive control
of an electric utility where such
installations:
a. Consist of service drops or service
laterals, and associated metering, or
b. Are located in legally established
easements, rights-of-way, or by
other agreements either designated
by or recognized by public service
commissions, utility commissions,
or other regulatory agencies having
jurisdiction for such installations, or
c. Are on property owned or leased by
the electric utility for the purpose ofcommunications,
metering, generation,
control, transformation,
transmission, or distribution of electric
energy.” This portion of the
scope lays out the parameters for
NFPA 70E’s exclusions. Many of
these exclusions could end in the
next edition according to committee
members.
NESC 2007 includes “the electric supply
conductors and equipment … (including)
electric supply stations, that are
accessible only to qualified personnel.”
NFPA 70E is more prescriptive than
the NESC. It gives tables describing the
PPE while the NESC only requires workers
to wear clothing with an “arc rating”
equal to the predicted hazard. The NESC
has the following important provisions:
• Clothing requirements effective as of
January 1, 2009;
• Arc flash assessment calculations required;
• If exposure greater than 2 cal/cm2, employer
shall require employees to wear
clothing that has an effective arc rating
not less than the anticipated level of arc
energy;
• Secondary portions of systems require
4 cal/cm2 PPE, engineering controls due
to high energies, and no arc calculations
are required on secondary systems unlike
NFPA 70E; and
• Exemption for “greater hazards” not
well defined (group intended this to allow
heat stress, etc in line work).
The NESC will lead utilities to much
more protection than the OSHA current
standard and recent OSHA proposed language
indicates OSHA is planning to implement
the NESC 2007 language into
law in the future.
Calculating arc flash energies for utility
work will be critical but it leaves utilities
some leeway in critical areas. The
NESC is not prescriptive on clothing design
or hood requirements leaving the
market free to design protective systems
which are more comfortable and wearable
than the NFPA 70E market is currently
offered. Though NFPA 70E
seems prescriptive this is a bit of a misunderstanding.
The tables are prescriptive
but companies who do calculations
are left with much more freedom than
those using the tables. Companies are
looking at more comfortable systems and
systems which are easier to don and doff
in the event of an arc. Items which have
made their debut in the last few months
are lightweight balaclava hoods (firefighter
style hoods) which can be worn
under a face shield to meet HRC 2* type
applications but some companies are using
them with a new arc goggle to allow
more vision and less restriction for line
workers when they are climbing or working
in cold conditions. Other companies
are evaluating and using flash suits with
long coats and leggings. This meets the
stated requirements to protect the whole
body in arc events in many cases.
More study is ongoing on new designs
of flash suits which are easier to don for
work and easier to doff in an arc event to
allow quicker escape. No matter what
your exposure, the “new sheriff” of an
applicable standard will cause you to
think about your hazards in new ways.
Creativity loves constraint. When standards
bring out new requirements companies
develop new ways to protect and
comply with the standard. Engineering
changes and PPE changes will be driving
the arc market for quite some time.
Stay tuned to see the new solutions and
to find new and improved ways to protect
your workers.
Hugh Hoagland, ArcWear.com/e-
Hazard.com does training and
consulting in arc flash. He may be
reached at hugh@arcwear.com
