AC power system in ISPI modules will be installed
to serve the requirements of (a) the DC plant, (b)
air conditioning equipment, (c) the fire protection
system and (d) general lighting and receptacles.
AC power systems will conform to National Fire Protection
Association (NFPA) Standard 70 (National Electrical
POWER SOURCE: AC
power will typically be delivered to the module from
the local site’s
service point. Power will be delivered at the lowest
utilization voltage and frequency typical for the
local area (for example: 208/120V, 3-phase, 60Hz
for US installations). Typically, no transformation
of power to a lower voltage is done in ISP shelters.
In some cases, site power may be at a higher voltage
than the ratings of systems within the module.
In these cases, a transformer outside the module
will step the voltage down to the utilization level. “Normal” power
will generally be delivered from the local utility
system. “Standby” power will be delivered
from on-site standby generators, provided either
by the site owner or by ISP.
PANELBOARD: Distribution of AC power to loads
within the shelter will be from a small panel board
installed in the shelter. Typically, the panel board
will be installed in a location near the entry door.
The shelter panel board will be in a NEMA Type 1, surface-mount
enclosure. Minimum panel requirements are 240V, 100A,
10,000AIC, and 20 circuits.
wiring in the modules will use copper conductors, with
600-volt insulation. Wiring will be protected from damage
the modules, lighting will be fluorescent. Minimum lighting
consists of a single 4-foot, 4-tube fixture. Modules
larger than 10’ x 10’ will have additional
fixtures installed as appropriate to provide light at
all equipment racks. A motion sensor installed near the
entry door will control lights. Motion sensors will automatically
turn lights off after personnel leave the shelter to
prolong lamp life.
will be provided at the outside door of the module at
sites where it is appropriate. Local practices and/or
sitting requirements may make outdoor lighting unnecessary
or unwanted. Where installed, outdoor lighting shall
use high-pressure sodium fixtures. The fixtures will
be controlled by photocell, to turn the light on at dusk
and off at dawn.
lights will be installed inside modules to provide light
in case of a power outage.
receptacles will be installed to provide power for small
tools and maintenance test equipment. Sufficient numbers
of receptacles will be installed so as to minimize the
need for extension cords for test equipment used at any
system grounding will conform to requirements of both
the National Electrical Code and Bellcore standards.
The AC power system’s grounding point will be at
its source (the local utility or the secondary of the
transformer from which the low-voltage power is derived).
The panel board’s ground bar will be bonded to
the shelter’s steel frame.