{"id":779,"date":"2022-08-06T10:23:34","date_gmt":"2022-08-06T10:23:34","guid":{"rendered":"https:\/\/the-regs.co.uk\/blog\/?p=779"},"modified":"2022-08-06T10:23:37","modified_gmt":"2022-08-06T10:23:37","slug":"all-about-rcds-residual-current-devices","status":"publish","type":"post","link":"https:\/\/the-regs.co.uk\/blog\/?p=779","title":{"rendered":"All About RCDs (residual current devices)"},"content":{"rendered":"\n

RCD description<\/strong><\/p>\n\n\n\n

An RCD ‘Residual Current Device’ is an electrical device that monitors the current flowing through either an individual circuit such as an RCBO ‘residual current operated circuit-breaker with integral overcurrent protection’ or multiple circuits within an installation using an RCCB ‘residual current operated circuit breaker without integral overcurrent protection’. Its purpose is to detect any current in a circuit that may be leaking to earth either through Line to Earth or Neutral to Earth.<\/p>\n\n\n\n

This is done by monitoring the current in the Line and Neutral conductors to ensure they are balanced, meaning what current flows into a circuit via the Line conductor should be the same as the current flowing out through the Neutral conductor. If there is any difference between the Line and Neutral current, it would indicate that some current within the circuit must be leaking to Earth.<\/p>\n\n\n\n

This leakage current is measured in milliamps ‘mA’ (1\/1000 amp) and if the leakage current reaches a pre-determined level, usually 30 mA ‘0.03 A’ the device will operate and isolate the supply from the circuit.<\/p>\n\n\n\n

As it is a much more sensitive device than a fuse or circuit breaker which require large amounts of currents before they trip under fault conditions, an RCD provides protection to the user of the installation minimising the chances of them receiving a potentially lethal electric shock which is often regarded as 50 mA ‘0.05 A’ or above.<\/p>\n\n\n\n

Common types of RCDs<\/strong><\/p>\n\n\n\n

AC: Ensures tripping for residual AC currents and is found in most domestic installations.<\/p>\n\n\n\n

A: Ensures tripping for all types of AC currents and pulsating DC currents.<\/p>\n\n\n\n

B: Ensures tripping for residual AC currents, pulsating DC currents and smooth DC currents.<\/p>\n\n\n\n

B+: Ensures tripping for residual AC currents, pulsating DC currents and smooth DC currents. It also ensures no unwanted tripping and detection of high frequency faults up to 20 kHz.<\/p>\n\n\n\n

Why we need different types<\/strong><\/p>\n\n\n\n

The abundance of modern technology we use these days can cause problems when selecting what type of RCD to use.<\/p>\n\n\n\n

This technology includes…<\/p>\n\n\n\n