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consumer unit design now make it easy to protect any individual
circuit with a combined CB/RCD (RCBO), making the use of
split-load boards unnecessary.
In domestic premises the use of 30 mA RCDs is required for the
protection of all socket outlets rated at not more than 20 A, for all
circuits in a bath or shower room and for cables embedded in walls
and partitions at a depth less than 50 mm. Socket outlets not
intended for general use, for example those provided for non-
portable equipment such as freezers, etc., are exempt from this
requirement, provided they are suitably labelled or identified.

4 Decide, whether the following statements are true or false in
relation to the information in the text. Change false statements
into true ones.
1. Modern developments in CB, RCD and consumer unit
design now make it difficult to protect any individual circuit.
2. All cables installed less than 50 mm from the surface of a
wall or partition (in the safe zones) if the installation is not
supervised, and also at any depth if the construction of the wall or
partition includes metallic parts.
3. In TT systems where the mass of earth is part of the fault
path, the minimum values of Zs given in the IEE Regulations may
be hard to satisfy.
4. The regulations recommend that the preferred method of
earth fault protection for installations in TT systems be achieved
by RCDs.
5. Climatic conditions will alter the resistance of the earth in
such a way that Ze may be satisfactory in dry weather, but not in
very wet.

5 Pick out from Text 1 all the verbs in the Passive Voice.

6 Put 5 questions to Text 1.

7 Working in pairs test each other’s ability to speak about
application of residual current devices.

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