Circuit Protection Devices
Manette Chen
Circuit protection since 2009 ★ Consumer unit & Surge protection ★ Servicing clients in Europe specially UK
The Consumer Unit, or distribution box is the most important electrical safety device in the home and workplace. Let's check out what circuit protection devices are installed in:
Main Switch
Isolates the whole consumer unit and all devices. If want to cut power to all circuits , Turning this switch to 'OFF'. Most consumer units are fitted with a 100A main switch, some use 63A 80A or bigger one 250A.
RCD - Residual Current Device
Protects a bank of circuits from earth leakage or 'Residual Current' - for example - cutting through the lawnmower cable. Protecting a bank of MCBs means that earth leakage on one circuit will cut power to all other circuits protected by that RCD and is considered a form of 'nuisance tripping'. The most common domestic RCD is rated at 80Amp 30mA. Which have type A type AC type B and up to 100A.
MCB - Mini Circuit Breaker
Protects cables and devices from overload and consequently fire. All MCBs must be used with an RCD in order that the circuit is also protected against earth leakage.MCBs amperages available in following: 6a, 10a, 16a, 20a, 32a 40a 50a 63a 80a 100a 125a. We having 3kA 6kA 10kA but most common used in UK is 10kA.
RCBO - Residual Current Breaker + Overload
A breaker which has the functionality of both and RCD and MCB, protecting against both overload and earth leakage. This offers complete circuit separation negating nuisance tripping. RCBOs are more expensive than MCBs. Which have type A type AC and up to 63A
SPD-Surge protector
