Wilson Electrics guidance
What the consumer unit does
The consumer unit distributes electricity around the property and protects the wiring against faults and excessive current. Modern designs can also provide residual-current and surge protection that many older arrangements lack.
RCBOs: one circuit, one protective device
An RCBO combines overcurrent protection with residual-current protection for an individual circuit. If one circuit develops a fault, only that circuit should disconnect. This can reduce the inconvenience and secondary risks created when one shared RCD disconnects several unrelated circuits.
Surge protection
A surge protection device helps limit short-duration overvoltages that could damage electronic equipment. Whether it is required is determined through the current BS 7671 assessment and the design of the proposed work, not simply by the value of one appliance.
When an upgrade may be sensible
- There is no suitable RCD protection for circuits that require it.
- The enclosure or internal equipment is damaged, overheated or unreliable.
- Protective devices are obsolete or unsuitable for planned alterations.
- Shared RCDs cause widespread loss of power when one circuit develops a fault.
- New circuits or increased load require a properly designed modern arrangement.
Testing comes first
Existing circuits must be assessed before being connected to a new consumer unit. Testing may identify insulation faults, broken conductors, unsuitable earthing or bonding, mixed circuits and other defects that must be addressed before safe reconnection.
A separate EICR is not always necessary immediately before an upgrade, but suitable inspection and testing of the installation is. The scope is explained in the quotation.
What Wilson Electrics specifies
Where a replacement is appropriate, Wilson Electrics normally specifies a metal consumer unit with individual Type A RCBOs, surge protection and sensible spare capacity. The exact equipment and protective arrangements depend on the installation.