What is a Type A RCD/RCBO?
RCBO stands for Residual Current Breaker with Over-Current.
RCD stands for Residual Current Device.
Type A RCD/RCBOs are used for installations that are subjected to alternating sinusoidal residual current and for residual pulsating direct current up to 6 mA.
These devices are installed to protect circuits where equipment with electronic components such as listed below are installed –
- Inverters
- IT Equipment
- Class II Equipment
- Lighting equipment including dimmers and LED drivers
- Induction hobs
- Electric vehicle charging equipment with smooth residual DC current less than 6 mA
Type A devices are also suitable for Type AC applications.
Type A devices will have the symbol below on them to indicate which waves of current they will operate with.
The main reason Type A devices have replaced Type AC devices is due to the amount of modern electrical equipment that contain inverters which invert AC current into DC current such as EV car chargers. When this happens the DC current sends a noise signal into the electrical installation which can ‘blind’ a traditional Type AC device meaning in a fault situation it may not operate as it cannot ‘see’ the fault. This has unfortunately led to some fatalities.
All new consumer units now installed must have Type A RCD/RCBO circuit protection. If you have an older Type AC device you should consider upgrading to a Type A device.
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