Yokogawa ADMAG AXR - Manual (Page 192)

IM 01E30D01-01EN
3
IM 01E30D01-01EN
(2) Flameproof Metal Conduit Wiring
• For the flameproof metal conduit wiring or
insulated wires shall be used as recommended
by the USER’S GUIDELINES for Electrical
Installations for Explosive Gas Atmospheres in
General Industry, published in 1994.
• For conduit pipes, heavy-gauge steel conduits
conforming to JIS C 8305 Standard shall be
used.
• Flameproof sealing fittings shall be used in the
vicinity of the wiring connections, and those
fittings shall be filled with sealing compounds to
complete sealing of the apparatus. In addition,
to prevent explosive gases, moisture, or flame
caused by explosion form being propagated
through the conduit, always provide sealing
fittings to complete sealing of the conduit in the
following locations:
(a) In the boundaries between the hazardous
and non-hazardous locations.
(b) In the boundaries where there is a different
classification of hazardous location.
• For the connections of the apparatus with a
conduit pipe or its associated accessories,
G-type parallel pipe threads (JIS B 0202) shall
be used to provide a minimum of five-thread
engagement to complete tightness. In addition,
since these parallel threads do not have sealing
property, nonhardening sealant such as liquid
gaskets shall thus be applied to those threads
for ensuring waterproofness.
• If metal conduits need flexibility, use flameproof
flexible fittings.
6. Maintenance of Flameproof
Apparatus
To maintain the flameproof apparatus, do
the following. (For details, see Chapter 10
“MAINTENANCE OF EXPLOSION-PROTECTED
ELECTRICAL INSTALLATION” in the USER’S
GUIDELINES for Electrical Installations for
Explosive Gas Atmospheres in General Industry.)
(1) Maintenance servicing with the power on.
Flameproof apparatus shall not be maintenance-
serviced with its power turned on. However, in cases
where maintenance servicing is to be conducted
with the power turned on, with the equipment cover
removed, always use a gas detector to check that
there is no explosive gas in that location. If it cannot
be checked whether an explosive gas is present or
not, maintenance servicing shall be limited to the
following two items:
(a) Visual inspection
Visually inspect the flameproof apparatus, metal
conduits, and cables for damage or corrosion,
and other mechanical and structural defects.
(b) Zero and span adjustments
These adjustments should be made only to
the extent that they can be conducted from the
outside without opening the equipment cover.
In doing this, great care must be taken not to
cause mechanical sparks with tools.
(2) Repair
If the flameproof apparatus requires repair, turn
off the power and transport it to a safety (non-
hazardous) location. Observe the following points
before attempting to repair the apparatus.
(a) Make only such electrical and mechanical
repairs as will restore the apparatus to its
original condition. For the flameproof apparatus,
the gaps and path lengths of joints and
mating surfaces, and mechanical strength
of enclosures are critical factors in explosion
protection. Exercise great care not to damage
the joints or shock the enclosure.
(b) If any damage occurs in threads, joints
or mating surfaces, inspection windows,
connections between the transmitter and
terminal box, shrouds or clamps, or external
wiring connections which are essential in
flameproofness, contact Yokogawa Electric
Corporation.