Page 237 - Electrical Installation in Hazardous Area

General requirements for explosion protected apparatus 201

A

E

G

A = Sealing washer between enclosure and gland
B = Filling compound
C = Gland fixing holes
D = Gland body
E = Compound retaining element
F = Insulated cable cores
G = Cable inner/outer sheath
Note: Armoured cables will additionally have an armour clamp and
outer weather seal

Fig. 8.6 Detail of compound sealed gland

Conduit entries are not usual in the UK but may be used. The normally
acceptable conduit is solid drawn to ensure protection from the environ-
ment, and screwed entry into the apparatus. As the conduit forms part of
the earthing or bonding network, inadvertently if not deliberately, its joints
and entries should be protected against environmental damage, and the
prevention of passage of explosive atmosphere down its inside sealing, by
such things as stopping boxes, is required.
The manufacturer of apparatus normally provides entry holes for cable
or conduit, and often more than one to permit flexibility. It is essential that
these are closed when not used to protect the enclosure integrity, and plugs
for such holes need to be secure. They should only be removable with the
aid of a tool with the problems which that creates (see Section 8.5.1).

8.1.6 Additional requirements for particular types of apparatus

Certain types of apparatus are considered to have specific problems and
there are thus additional requirements for these.