MK Sentry RCD 100A 30MA 230V DP Type A 2 Module

Product Information

Assuming an AC Type RCD will suit every installation is incorrect and RCDs shall be selected according to the equipment which is likely to be used within the installation. Type AC RCDs shall only be selected where it can be assured that there is not and will not be any residual DC fault current on the circuit. The method of installation relating to protective earthing will depend on the operational leakage current (protective conductor current) – see 543.7. The use of a 30mA RCD may be required for several reasons; cable installation, location / application area for the pump etc. Take note of 531.3.2 Operational leakage current (protective conductor current) for the circuit should not exceed 30% of the RCD sensitivity.

NOTE 4: For guidance on the correct use of RCDs for household and similar use, see PD IEC/TR 62350. Solar photovoltaic systems incorporate inverters to convert DC to AC for use either within the electrical installation or to be supplied to the National Grid. Some inverters may provide galvanic or electrical separation between the AC mains supply and the DC side of the PV array. Where this is not the case, some manufacturer’s instructions state that Type B RCDs to BS EN 62423 must be used.It should be noted that the residual DC leakage current can vary with motor speed and cable length. There are many different RCD types available, each being suitable for different equipment types, as identified in Regulation 531.3.3 of BS 7671:2018. These are installed to protect circuits where equipment with electronic components are installed such as The term general purpose relating to Type AC devices should not be taken out of context i.e. it is the most basic RCD, suitable for detecting a simple full sine wave residual current at 50Hz. The advent of new technologies has created different challenges for the electrical designer and installer. Some modern equipment can create DC residual fault current. Such items include, variable-speed drives, LED lighting, washing machines, dishwashers and tumble dryers.

In some other countries in Europe (perhaps not coincidentally the ones commonly using 3-phase supply to homes), it's much easier to find type-A or even type-B. Type A Prices: As with any component, normal competitive / market forces apply. A substantial increase in UK demand for a particular product, will normally result in a reduction in unit price, providing the demand does no exceed the availability. All types of electrical installations could be affected, it depends on the equipment which has been installed. Examples include:The fault current (If) contains mixed frequency components between 10Hz (minimum motor frequency) and 1kHz (maximum inverter switching frequency) ***. Type B devices are also suitable for Type AC, Type A and Type F applications. How do I test the different Types of RCD?

Type A RCDs are not designed to detect smooth dc residual currents. They will still trip within safe limits with < 6 mA smooth dc superimposed on a 50Hz pulsed residual current.i) RCD Type AC: RCD tripping on alternating sinusoidal residual current, suddenly applied or smoothly

I believe the article makes it clear that the their are 4 Types of RCD that may need to be considered - Quote from the article - RCDs work by monitoring the flow of current in a circuit's live conductors and, if the flow of current is imbalanced due to an earth leakage current of a set nominal value, the device will trip to cut off the supply to the circuit. Whilst RCDs have a nominal tripping current (IΔn), they may trip below the nominal value; for instance, a 30 mA RCD is required to trip at a current between 18 mA to 28 mA. What I would say is look at the article as a whole, as it makes it quite clear that 531.3.3 refers to 4 Types of RCD, and the points to consider when selecting RCDs for circuits containing various items of equipment. It also makes the point about consulting the manufacturer of the equipment for advice.There's never going to be a perfect solution but there does need to be a less complex solution than there is.