Rice Lake EL232 XPCD Explosion Proof Remote Serial Display - Manual (Page 6)

2 EL232 XPCD Installation Manual
The push buttons, rotary switches and sealing fittings are all attached to the enclosure via drilled and
tapped holes in the enclosure. Just as with the flange, all threaded operators and fittings carefully control
the flame path.
Explosion
HAZARDOUS
AREA
High temperature
gases
Cooling from
conduction of heat
along the threads
There must be a minimum of five full
threads of engagement of a 2–A
2–B fit for a Group C enclosure.
Group B increases this to eight full
threads of engagement.
Propagation of gas due to
pressure from an internal
explosion is along the
threads
Shaft clearance
not to exceed 0.00033”
Cross–section of a
shaft-type threaded
operator
INSIDE OF
ENCLOSURE
Lower
temperature
gases
Enlarged view
below