NFPA Journal - Winter 2021 - 58

In Compliance The Experts
SELECTIONS FROM RECENT
BLOGS ON CODES AND
STANDARDS BY NFPA STAFF
Brian O'Connor, a technical services engineer at
NFPA, on the requirements in NFPA 855, Standard
for the Installation of Energy Storage Systems, for
installing ESS in one- and two-family residential
homes:
The residential chapter of NFPA 855 addresses the
installation of residential ESS units between 1 kilowatt
hours (kWh) and 20 kWh; anything exceeding that
is treated the same as a commercial installation and
must comply with the commercial requirements of
the rest of the standard. There are also limitations on
how much total energy can be stored in certain areas
of a household.
There must be an effective ground-fault current path
created to ensure a safe electrical system-basically,
this is the creation of a low-impedance electrically
conductive path that facilitates the operation of the
overcurrent protective device. This path must be
capable of safely carrying the maximum ground-fault
current likely to be imposed on it from any point on
the electrical wiring system where a ground fault
may occur. The earth itself is not considered an
effective ground-fault current path, so sticking the
wire in the ground is not enough.
Instead, this is accomplished through a propNFPA
855 limits the number of locations
that residential energy storage systems
can be installed. GETTY IMAGES
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versions of
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at nfpa.org/
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NFPA 855 permits residential ESS to be installed
only in the following areas: attached or detached
garages; on exterior walls or outdoors at least three
feet away from doors or windows; or in utility closets,
and storage or utility spaces. If the ESS is in the home,
interconnected smoke alarms are required to be
installed throughout the house, including any garages
or rooms housing ESS units.
NFPA 855 also includes requirements for houses
that will use electric vehicles as energy storage systems.
For this, there are two main requirements. First,
any electric vehicle used to power a dwelling while
parked needs to comply with the manufacturer's
instructions and NFPA 70®
, National Electrical Code®
.
Second, the use of a vehicle to power a home cannot
exceed 30 days.
For related training, articles, research reports, and
more, check out nfpa.org/ESS.
Dean Austin, senior electrical content specialist at
NFPA, on understanding the essentials of electrical
grounding:
I'm sure many of you are thinking you can just stick a
wire in the ground and call it good, right? Not exactly.
58 | NFPA JOURNAL * WINTER 2021
erly installed grounding electrode system, which
stabilizes voltage and helps to clear
ground faults. This system is the
connection to earth through the
code-required grounding electrodes.
The grounding electrodes
then get connected back to the
building's electrical service via a
grounding electrode conductor
(GEC). The GEC, at the building or
structure's service, is terminated
on the neutral bar in the electrical
service equipment alongside the
grounded (neutral) conductor. The
neutral bar is bonded (connected)
to the service equipment enclosure
through a main bonding jumper,
which in turn creates an effective
ground-fault current path for the
electrical system.
Christopher Coache, a senior
electrical specialist at NFPA, on
NFPA 70E®, Standard for Electrical Safety in the
Workplace®, and maintaining a safe working space:
The National Electrical Code® (NEC)®
Section 110.26
requires adequate working space for all electrical
equipment. Section 110.26(A) requires a clear space
at least 30 inches wide and 36 inches deep if the
equipment is likely to be worked on while energized.
This space is necessary to allow workers room to
perform tasks and also room to move if something
goes wrong. Section 110.3 requires that all equipment
be placed into an electrically safe work condition
(ESWC), unless there is proper justification for
the equipment to be energized. NEC 110.26(A) still
applies even if equipment will be in an ESWC.
It takes experience to protect workers while
preserving valuable floor space. Electrical safety is
always affected by installation, maintenance, and
work practices. Some equipment is unlikely to be
worked on while energized; there are also installation
methods that can minimize the amount of working
space required. Without a holistic approach to electrical
safety, however, the full working space of NEC
110.26(A) will be necessary-installations need the
clear space necessary to keep workers safe.
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NFPA Journal - Winter 2021

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