Incredible shrinking circuit breakers - MCB, RCD, RCBO breakers to AFDD

Overcurrent protection has come a long way from the humble fuse to the latest AFDD (AFCI technology). The first bit of new kit was the Miniature Circuit Breaker MCB (Anyone remember the Crabtree C50?) Then we moved away from just short circuit protection with the introduction of the Residual Current Device (RCD) which has been known by lots of names RCCB, ELCB or a Ground Fault Circuit Interrupter (GFCI for our US friends). RCD technology was combined with MCB to give us the RCBO Residual Current Breaker with Overload.

At every stage of this, circuit breaker evolution devices start large, then shrink. Then grow again as they are combined with other technologies into a combined device.

The 18th Edition of the Wiring Regulations BS7671 introduced the Arc Fault Detection Devices AFDD to the UK market. AFDDs identify dangerous faults caused by arcing in electrical circuits and are designed to switch off the circuit before a fire occurs. Again, these started as two modules and in some cases 3 modules wide. Electricians then started to worry that consumer units would need to be the size of a suitcase.

The clever boffins at Seimens have done it again and managed to shrink all the circuit protection functions into a one single module DIN rail device. RCD + MCB + AFDD.

In this video, Gary Hayers and Joe Robinson talk us through the circuit breaker evolution.

The devices featured here are from Crabtree - which is a brand of Seimens sitting under the Electrium Sales banner alongside Wylex.

The 18th Edition also increased the attention towards surge protection devices - which we feature in this video.

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