16th Edition (reference only) – NOW superseded by the 17th Edition IEE Regulations.

chapter 5

chapter 6

Installation control and protection
  3.1 - Introduction 3.5 - High temperature protection
  3.2 - Switching 3.6 - Overload currents
  3.3 - Isolation 3.7 - Protection from faults
3.4 - Electric shock protection

3.8 - Short circuit and overload
------- protection

3.3.2 Isolator situation

Isolators are required for all circuits and for all equipment, and must be adjacent to the system protected.

As for a switch, the isolator must be arranged so that it will not close unintentionally due to vibration or other mechanical effect. It must also, where remote from the circuit protected, be provided with a means of locking in the OFF position to ensure that it is not reclosed whilst the circuit is being worked on. The isolator should also be provided, where necessary, with means to prevent reclosure in these circumstances. This may be a padlock system to enable the device to be locked in the OFF position, a handle which is removable in the off position only, etc.

It is particularly important for motors and their starters to be provided with adjacent isolation to enable safe maintenance.

The special requirements for isolating discharge lamp circuits operating at voltages higher than low voltage will be considered in {7.12.2}.


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Extracted from The Electricians Guide Fifth Edition
by John Whitfield

Published by EPA Press Click Here to order your Copy.

Click here for list of abbreviations