BS 5972:1980

Foreword
Cooperating organizations
Specification
Section one. General
1 Scope
2 References
3 Definitions
4 General test requirements
5 Classification
6 Marking
Section two. Photoelectric control units
7 Construction
8 Insulation resistance and electric strength
9 Creepage distances and clearances
10 Electrical performance
11 Photometric performance
Section three. Sockets
12 Mechanical construction
13 Resistance to heat, fire and tracking
14 Ingress of moisture
15 Electrical contacts and connections
16 Creepage distances and clearances
17 Terminations
18 Protection against electric shock
19 Insulation resistance and electric strength
20 Provision for earthing
Appendices
A Test for switching
B Test of illuminance levels of switching of PECU
C Desirable features of design of PECU and sockets
Tables
1 Insulation resistance and electric strength of PECU
2 Minimum creepage distances and clearances of PECU
Figures
1 Blade dimensions of one-part controls
2 Switching test circuit
3 Typical arrangement of a socket
4 Details of photocell socket design
5 Typical apparatus for test of illuminance levels for
    switching

Requirements for photo-electric control units and associated sockets for operation on supply voltages not exceeding 250 V and capable of switching a current not exceeding 10 A. Includes requirements for electrical and photometric performances.

This standard specifies requirements for the safety and performance of:

1. photoelectric control units (PECU);
2. photocell sockets.

Both items are for use in switching road lighting lanterns, road traffic signs and other apparatus in response to variations in daylight. The PECU and sockets are for operation on supply voltages not exceeding 250 V to earth or between terminals, and for switching a current not exceeding 10 A.