BS 4683-2:1971

Co-operating organizations
Introduction
Foreword
Specification
Section 1. General
1 Scope
2 Definitions
3 Grouping of enclosures
4 Enclosed apparatus
5 Joints
6 Operating rods (spindles)
7 Shafts and bearings
8 Inspection windows
9 Cover glasses for lighting fittings
10 Breathing and draining devices
11 Fastenings
12 Mechanical strength
13 Connection of external conductors and cables
14 Marking
Section 2. Checks and tests
15 Type checks and tests
16 Routine checks and tests
Section 3. Special requirements for group IIC
            enclosures
17 Compliance with Section 1
18 Volume
19 Joints
20 Operating rods, shafts and bearings
21 Tests
Appendices
A Cements and sealing materials
B Alignment with IEC Publication 79-1
Tables
1 Groups I, IIA and IIB enclosures
2 Group IIC enclosures
3 To show the group of enclosure suitable for a
     particular flammable gas or vapour
Figures
1-9 Typical joints
10 Example of the use of a dowel pin to permit
     indirect observation of the closeness of fit of a
     joint
11 Typical plain fixed gland
12 Typical labyrinth gland
13 Typical plain floating gland
14 Sleeve bearings where a < g
15 Sleeve bearings where a > g
16 Typical window mountings
17 Typical means of shrouding nuts, bolts, screws,
     etc. used for securing covers
18 Indirect entry of cable (Type X)
19 Direct entry of cable (Type Y)
20 Definition of pressure rise time
21 Illustration of requirements of 15.3.2
22 Spigot joint in Group IIC enclosure
23 Threaded joint in Group IIC enclosure

Prescribes constructional features for flameproof enclosures for electrical apparatus for use in flammable or explosive gases or vapours and test requirements to be met. Enclosures are grouped according to their industrial applications and to the dimensions of permitted gaps. Indicates atmospheres for which the groups are appropriate.