Electrical Supply Requirements - Pepperl+Fuchs 1001A Series Installation And Operation Manual

Model 1001A Installation and Operation Manual
General Wiring Requirements
WARNING! This device contains electrical parts which
can cause shock or injury.
All electrical connections, conduit, and fi ttings on the protected
enclosure must be suitable for the hazardous location in which
they are installed. In addition, all conduit and wire must be
installed in accordance with NEC as required and all relevant
plant and local codes.
Note: Do not use seals on conduit used as a protected
"wireway" to supply protective gas to adjacent protected
enclosures. The same conduit can be utilized for both electrical
and pneumatic service to an adjacent protected enclosure(s),
provided the conduit is oversized to allow a minimum free
clearance equal to or larger than the pipe size required between
multiple enclosures as stated on page 6, "Getting Started."
Enclosure Power Requirements
The protected enclosure(s) electrical power source must
originate from a circuit breaker or fused disconnect suitable for
the hazardous location in which it is installed. The switch must
be located within fi fty (50) feet of the protected enclosure(s) and
the protection system and be properly marked.
Alarm Signal Requirements
The WPSA style pressure switch requires a 120 VAC power
supply in addition to the alarm signal. The WPS and WPSA
Style systems alarm signal may originate from the protected
enclosure if the alarm signal is disconnected by the protected
enclosure's circuit breaker or fused disconnect as stated in
Enclosure Power Requirements above.
The protected enclosure(s) alarm signal power may also
originate from outside of the protected enclosure. In this
application, the protected enclosure may be used as a
"wireway" to pass alarm signal wiring from the power source to
the alarm device, if the wiring is isolated and properly labeled.
In addition, appropriate conduit seals must be provided outside
of the protected enclosure separately.
IMPORTANT NOTE: NFPA 496 requires the use of an
alarm or an indicator to detect the loss of safe enclosure
pressure. In addition, the NFPA 496 requires that if
an indicator alone is utilized, a protective gas supply
alarm must also be installed between the last valve in
the protective gas supply and the protected enclosure.
Therefore, the protective gas supply to all LPS Style
systems must be equipped with the above mentioned
protective gas supply alarm. Exception: systems utilizing
an EPSK or GPSK enclosure pressure loss alarm switch
accessory will satisfy the above mentioned NFPA
requirement.

Electrical Supply Requirements

Typical Enclosure Wiring Methods
In a general sense, protected enclosures should be wired
similar to explosion proof enclosures, in accordance with Article
500 of the National Electric Code - NFPA 70.
Single conductor wiring should be placed in rigid metal conduit,
seal-fl ex conduit or other mediums approved for use in the
hazardous location surrounding the protected enclosure.
Additionally, NFPA 496 requires the use of approved seals on
all pressurized enclosure conduit wiring entries, in accordance
with NFPA 70. Furthermore, the use of an approved seal is
simply the most practical way to prevent excessive leakage
through conduit connections.
However, while explosion proof enclosures require conduit
seals on all cable entries, in accordance with NFPA 70. Other
methods of sealed cable entries that are suitable for hazardous
locations can be used, such as compression glands.
In conclusion, there are two primary goals. First, the installer
should ensure that all associated wiring and cable is protected
by pressurization or other means, such as explosion proof
conduit or intrinsic safety barriers. Secondly, the installer should
ensure that all associated conduit and wireways are sealed
to conserve protective gas, unless they are used to supply
protective gas to other enclosures or devices.
Typical Enclosure Wiring Connections
Protected enclosure
Conduit
Seal
Conduit
Seal
Gland
fi tting
Cable
Conduit
Seal
Pressurized
raceway
or device
Explosion
proof device
Intrinsically
safe or fi ber
optic device
Intrinsically
safe or fi ber
optic device
Independently
pressurized
device
Adjacent
pressurized
device
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