| The 17th Edition of the wiring
regulations (BS7671) came into effect in 2008. One of the
biggest changes from the 16th Edition was in the increased requirement for RCD
protection of domestic installations. Previously, RCDs were only
required to protect socket outlets used to power outdoor equipment
or where disconnection times could not be achieved or for special
locations such as bathrooms.
two RCDs protecting separate banks
of circuits
on a modern domestic Consumer Unit
A summary of the new RCD requirements are
as follows:-
 |
All socket outlets should have 30mA RCD
protection |
|
All circuits in a room with a fixed
bath or shower should have 30mA RCD protection |
|
All cable buried beneath the
plaster surface of a wall or partition should have 30mA RCD
protection |
|
All cables concealed in metal stud
partitions (common in new builds) should have 30mA RCD protection |
|
Installations should be divided up
into circuits so as to take account of danger and inconvenience
caused by a single fault - in other words, a single RCD should
not protect an entire installation - in the picture above only
half of the circuits will be disconnected if one of the two RCDs
trips due to a fault.
|
|
SUMMARY TABLE |
| Regulation |
Relating to |
30mA RCDs required for |
| 411.3.3 |
Sockets up to
20A rating for general use by ordinary persons |
Upstairs
sockets
Downstairs sockets
Kitchen sockets
Cooker outlet with integral 13A socket
Garage sockets
Plus any other sockets up to 20A rated |
| 701.411.3.3 |
All circuits
in a room with a fixed bath or shower |
Shower
circuit
Lighting Circuit
Heating Circuit
Ventilation circuit
Shaver socket
Plus other circuits |
522.6.6
522.6.7
522.6.8 |
All circuits
buried in a wall or partition at less than 50mm and without mechanical
protection |
Downstairs
lighting
Upstairs lighting
Immersion heater
Burglar alarm
Smoke alarms
Plus any other circuit |
|
