Changes to the wiring regulations with the release of the 18th Edition in July, Manufacturers have worked hard to produce new devices, accessories and pre loaded consumer unit ready for January 2019. Hager, Schneider, Fusebox and LIVE Electrical have brand new consumer units. We now have consumer units with RCCB and Surge Protection Devices to comply with 18th edition wiring regulations. We stock a wide range of ways and different types of consumer units ready for next day delivery

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What you need to know when choosing a consumer unit?

Protection against overvoltage’s


“These devices shall be protected by an overcurrent protective device. To achieve overload protection of RCCB switches the rated current of the over-current protective device shall be selected according to the manufacturers instructions.”


“...However, overload protection shall not solely be based on the use of diversity factors of the downstream circuits. To achieve overload protection of RCCBs or switches, the rated current of the Overcurrent Protective Device (OCPD) shall be selected according to the manufacturers instructions.”

Method 1

Ensure the sum of the rated current of the downstream MCBs do not exceed the rated

current of the switch or RCCB (Inc). This method would however need to consider the

consequences of any spare ways and later additions.

Method 2

Ensure that the rated current of a switch or RCCB (Inc), stated by the assembly

manufacturer, is not less than the rating of the upstream OCPD. For a domestic installation

this could be a 100A cut-out fuse.

Method 3

Select a consumer unit or distribution assembly that only utilises RCBOs on outgoing

circuits. Consideration will still need to be given as to the rated current of the main switch.
View Examples

RCD Selection (531.3.3)

In the presence of DC components and frequencies. The appropriate RCD shall be selected

View Examples

Arc Fault Detection (421.1.7)

“Devices conforming to BS EN 62606 are recommended as a means of providing additional protection against fire caused by arc faults in ac final circuits.” Page 10

Arc fault protection devices (AFDD) use microprocessors to identify

characteristic current flow and voltage curves that indicate an arc fault and

automatically trip the affected circuit.

View Potential Causes Examples