Yokogawa AXFA14G/C - Manual (Page 117)

IM 01E20C02-01E 12-6
12. EXPLOSION PROTECTED TYPE INSTRUMENT
• Apply a nonhardening sealant to the terminal box
connection port and to the threads on the flameproof
packing adapter for waterproofing.
• The same wiring as described below is required for
all of the terminal box connection ports except when
a four-wire cable is used for power input and signal
output with DC power supply.
Flameproof
packing adapter
Wiring metal
conduit
Flexible metal conduit
Tee
Drain plug
F0810.EPS
Apply a non-hardening
sealant to the threads
for waterproofing.
Figure 12.4.2 Typical Wiring Using Flexible Metal Conduit
Follow the procedure for flameproof packing adapter
setting. (refer to Figure 12.4.3)
CAUTION
Before fighting, confirm cable length from
terminal to flameproof packing adapter when
setting. Once it is tightened, loosening and re-
tightening may damage its sealing performance.
(a) Loosen the locking screw and remove the terminal
box cover.
(b) Measure the cable outer diameter in two directions
to within 0.1 mm.
(c) Calculate the average of the two diameters, and use
packing with an internal diameter nearest to this
value (see Table 12.4.1).
(d) Screw the flameproof packing adapter into the
terminal box until the O-ring touches the wiring
port (at least 6 full turns), and firmly tighten the
lock nut.
(e) Insert the cable through the union cover, the union
coupling, the clamp nut, the clamp ring, the gland,
the washer, the rubber packing, and the packing
box, in that order.
(f) Insert the end of the cable into the terminal box.
(g) Tighten the union cover to grip the cable. When
tightening the union cover, tighten approximately
one turn past the point where the cable will no
longer move up and down.
Proper tightening is important. If it is too tight, a
circuit break in the cable may occur; if not tight
enough, the flameproof effectiveness will be
compromised.
(h) Fasten the cable by tightening the clamp nut.
(i) Tighten the lock nut on the union cover.
(j) Connect the cable wires to each terminal.
F0811.EPS
Adapter body
Rubber packing
Washer
Packing box
Gland
Clamp ring
Clamp nut
Union coupling
Union cover
Wrench
O-ring
Lock nut
Wrench
Lock nut
Cable
Apply a non-
hardnening sealant to
the threads for
waterproofing.
Figure 12.4.3 Installing Flameproof Packing Adapter
(2-2) Cable Wiring Using Flameproof Metal
Conduit
• A seal fitting must be installed near the terminal box
connection port for a sealed construction.
• Apply a non-hardening sealant to the threads of the
terminal box connection port, flexible metal conduit
and seal fitting for waterproofing.
• The same wiring as described below is required for
all of the terminal box connection ports except when
a four-wire cable is used for power input and signal
output with DC power supply.
F0812.EPS
Non-hazardous
area
Hazardous area
Flameproof
heavy-gauge
steel conduit
Tee
Drain plug
Seal fitting
Gas sealing
device
Flameproof flrxible
metal conduit
After wrining, impregnate the
fitting with a compound to seal tubing.
Apply a non-hardening
sealant to the threads
of these fittings for
waterproofing
Figure 12.4.4 Typical Wiring Using Flameproof Metal
Conduit