Selection and Erection – Equipment
Supply
Sinusoidal A.C.
Form of Residual Current
Recommended type of symbol AC B A
Suddenly applied
Slowly rising
Pulsating D.C.
Suddenly applied
Slowly rising
Smooth D.C.
Figure D 7.2 RCD d.c. selection criteria.
In a TT installation, where a single RCD protects the whole installation, it is essential that the device is placed at the origin of the installation (i.e. adjacent to the electricity meter). The connections and any switchgear between the RCD and the electricity supplier’s meter is required to meet the requirements for protection by the use of Class II equipment or equivalent insulation (531.4.1).
131
D