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 IAEI News>Focus on the Code >CMP-15
Question
1. I
am looking for some informal assistance in the
application of NFPA 70, Article 701, to our municipal
fire stations. These stations have residential quarters
and are manned 24 hours a day. I have taken the position
that standby power to a fire station is necessary for
fire fighting operations, communications, and equipment.
I have used other jurisdictions, Red Cross disaster
training, NEC 701-2(FPN) [1999 NEC], as well as my own
judgment to arrive at this conclusion. That position is
being questioned. The
plans show a generator feeding the stations that is not
adequate for the entire load. No load shedding is
provided and the generator replaces the utility supply
through an automatic transfer switch. The submitter
wants to call the generator at each station an optional
standby system per NEC Article 702. I have asked for
load shedding or an alternate design as called out by
701-6. Are there
any other guidelines or advice you can provide me to
help justify a decision when backup power to a fire
station should be legally required or optional standby
power? Thank you. — S.D. Answer 1. The
scope of Article 701 covers the provisions that apply to the electrical
safety for the installation, operation, and maintenance of legally required
standby systems to supply power for illumination or power when the normal
electrical supply or system is interrupted. By definition, legally
required standby systems are those systems required and
so classed as legally required standby by municipal,
state, federal, or other codes or by any governmental
agency having jurisdiction. That means that the other
codes adopted by any agency having jurisdiction list the
requirements for the installation of a legally required
standby system. These are normally building codes such
as NFPA 5000, Section 12.8 and 12.9; NFPA 101, Sections
14.29, 15.2.9, and 7.9; and the International
Building Code. The NEC covers how
to install the emergency system, test, and maintain the
systems. All requirements as to what items are connected
to the legally required standby system are normally
reflected in the building code or other adopted life
safety requirements. With regards to your
reference to Article 701.2(FPN), if you will review
Article 90.5(C), you will see that this is explanatory
material for informational purposes only and is not
enforceable as requirements of this Code. I hope this helps in you
understand the requirements in the National
Electrical Code. — Robert Duncan, CMP-15 | Return
to top | Question
2. How
can I find information on how to wire fire pumps
properly? — A.N. Article 695.1 Scope. (A) Covered. This article covers the installation of
the following: (1) Electric power sources and interconnecting
circuits (2) Switching and control equipment dedicated to fire
pump drivers. NFPA 20, Stationary Pumps for Fire
Protection, deals with the selection and installation of
pumps supplying water for private fire protection. This
standard does not cover the requirements for
installation wiring of fire pumps. I’m sure you already know the
above information, so I will try to list some of the
concerns in wiring a fire pump. One of the main items in wiring a
fire pump is that it has a reliable source of power.
Check with the authority having jurisdiction on his
interpretation of what he will approve. The power source
shall be arranged so that a fire at one source will not
cause an interruption at the other source, see NFPA 20
for those requirements. Make sure that a listed fire pump,
transfer switch, fire pump controller, or a combination
controller and transfer switch are used in the
installation. The overcurrent devices shall be
selected or set to carry indefinitely the sum of the
locked-rotor current of the fire pump motor and the
pressure maintenance pump motor and the full-load
current of the associated fire pump accessory equipment
when connected to the power supply. The disconnecting means shall be
identified as suitable for use as service equipment and
be lockable in the closed position. Power circuits and
wiring methods shall comply with the requirements in
695.6(A) through (G). Controllers and transfer switches
for electric motor-driven fire pump controllers and
power transfer switches shall be located as close as
practicable to the motors that they control, and shall
be within sight of the motors, and shall be located or
protected so that they will not be damaged by water
escaping from pumps or pump connections. External control circuits that
extend outside the fire pump room shall be arranged so
that failure of any external circuit shall not prevent
the operation of a pump from all other internal or
external means. No undervoltage, phase-loss,
frequency-sensitive, or other sensors shall be installed
that automatically or manually prohibit actuation of the
motor contractor. The only exception is that a
phase-loss sensor shall be permitted only as a part of a
listed fire pump controller. Control conductors installed
between the fire pump power transfer switch and the
standby generator supplying the fire pump during normal
power loss shall be kept entirely independent of all
other wiring. They shall be protected to resist
potential damage by fire or structural failure. They
shall be permitted to be routed through a building
encased in 2 inches of concrete or within enclosed
construction dedicated to the fire pump circuits and
having a minimum 1-hour fire resistance rating, or
circuit protective systems with a minimum of 1-hour fire
resistance, and shall be installed in accordance with
their listing. –Robert C. Duncan, CMP-15 | Return
to top | The views of the authors of Focus on
the Code and the editor are provided solely as a public service. |
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