C.B. WALL PATTERN
Flameproof C.B. telephone
Specially designed for outdoor use, and is particularly suitable for railway and shipyards, docks or chemical factories, petroleum refineries and other places where it may be exposed to flammable vapours or atmospheres. The ordinary type of instrument is unsuitable in these cases, both electrically and mechanically.
The cast-iron case is watertight and the inner door is fastened by screw
locks requiring a special key for opening. The outer door effectually protects
the micro-telephone when not in use and the drip-proof cowl fitted on top
protects the ringer gongs, without deadening the sound. The incoming lines are
disconnected by an isolating switch which is operated when the inner door is
opened. All the apparatus, coils and wiring are specially treated to prevent
detrimental atmospheric effects. A terminal chamber to accommodate external
wiring is provided, normally one of two types to take either armoured cable with
three sealing glands, or with three bosses tapped for 3/4" conduit. If required a terminal chamber suitable for mineral insulated cable can also be supplied.
Certificate No. FLP 2378, certified by the Ministry of Power, as flameproof for Groups II and III.
Dimensions in brackets are the equivalent in cm.
Height - 20.75 inches (52.7)
Width - 12.5 inches (31.43)
Depth - 10 inches (25.4)