Introducing MCCBs fitted with Type B Earth leakage relay

17-01-2024

With the increasing use of equipment having an integral DC source, Type B Earth Leakage relays offer protection against both DC and AC leakage currents. 

The increasing usage of Electric Vehicle Chargers (EVC) has highlighted the need for protection against DC leakage currents. Whilst Type A Earth Leakage relays and RCDs tolerate up to 6mA DC leakage, they are not designed to protect against DC leakage. Type B devices are specifically designed to detect and protect against DC and AC leakage current.

When using multiple EVCs it is highly likely the potential DC leakage current will exceed 6mA. In Type A devices this causes a phenomenon known as “blinding” and results in them working erratically or not working at all.

In addition to EVCs producing DC leakage current, most equipment with some form of variable control also has the potential for DC leakage currents.

Type B devices are designed to protect against DC leakage currents and provide “future proofing” for installations. It is inevitable that potential DC leakage currents will increase, particularly with the installation of EVCs.

Fitting Type B Earth Leakage devices provides the correct protection and prevents the need for future costly shut downs to allow for upgrading of Type A devices.