Earthing and Bonding

Snag 22

It is advisable to properly terminate unused cores of a multicore cable. If unused cores of multi-core cables are left “floating” in an enclosure, they may make contact with live parts resulting in the other end of the conductor becoming unexpectedly live.

Solution

Although it is not strictly a circuit conductor, each unused core should be correctly terminated or insulated at both ends to eliminate the possibility of contact with a live terminal. This would ‘protect against dangers that may arise from contact with live parts of the installation, as required by Regulation 131.2.1.

Regulation 131.2.1

Persons and livestock shall be protected against dangers that may arise from contact with live parts of the installation. This protection can be achieved by one of the following methods:

(i)  Preventing a current passing through the body of any person or any livestock.

(ii) Limiting the current which can pass through a body to a non-hazardous valve.

Snags & Solutions A PRACTICAL GUIDE TO EVERYDAY ELECTRICAL PROBLEMS

‘Snags & Solutions’, NICEIC’s problem solving book, is now available in three parts, which cover many commonly-encountered electrical installation problems.  All parts take account of the requirements of BS 7671: 2008 (17^th Edition of the IEE Wiring Regulations), where appropriate. 

Part 1 addresses 53 problems relating to earthing and bonding, Part 2 covers 55 problems relating to wiring systems, and Part 3 covers 52 problems relating to inspection and testing.

Each book is available from NICEIC Direct at £15.  www.niceicdirect.com