Jargon Buster

There are many acronyms, abbreviations or technical words that are frequently used in electrical work that may not be fully understood. Here are a list of some of the more common ones that may help in your understanding of your electrical installation:

 

  • Consumer unit – modern term for a fuse box, generally consisting of a main switch, typically an RCD and several MCBs, or RCBOs
  • RCD (Residual Current Device) – this is designed to cut the power in the event of an earth short caused by a fault in the wiring or an appliance. It has a test button which should be tested monthly or quarterly as advised
  • MCB (mini circuit breaker) – modern day equivalent of the fuse. This does not require rewiring when it trips and can simply be reset. It generally trips when the current demand is greater than the rating stated on the MCB
  • RCBO (residual-current circuit breaker with overload protection) – quite simply an RCD and MCB in one
  • SWA (steel wired armoured) – a cable suitable for outdoor use or where there is risk of shock or impact

 

Illustrating typical examples of RCD, MCB and RCBO in a standard consumer unit

Illustrating typical examples of RCD, MCB and RCBO in a standard consumer unit