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

Product Information

Type AC RCDs (General Type), which are most commonly installed in dwellings, are designed to be used for alternating sinusoidal residual current to protect equipment which is resistive, capacitive or inductive and without any electronic components. An RCD monitors the earth leakage current in a circuit. It is constructed from coils of wire wound around a ferrite toroid core, one for each live conductor of the circuit protected. When a current imbalance between live conductors is detected, a voltage will be induced in the tripping coil which will disconnect the electrical supply to the protected circuit (see Figure 1). Swimming pool installations can be at risk when equipment such as pumps are being replaced with newer equipment incorporating VSDs, without any consideration as to whether the existing Type AC RCD is still suitable for the application. i.e. WWFC 1877 Mr Wolves Football supporter I guess - This article raises several questions commonly posed by Installers (see the question marks).

High frequency current components can saturate the RCD, preventing detection of 50Hz residual currents. Type F RCDs are not designed to detect smooth dc residual currents. They will still trip within safe limits with < 10 mA smooth dc superimposed on a 50Hz pulsed residual current.In a healthy circuit, the vector sum of the currents flowing in all live conductors should be nominally zero. When a fault occurs on a circuit causing a current to flow to earth, this creates an imbalance and trips the device. What is DC residual/fault current? I agree with you on that one, as electricians we have very little control over what will eventually be connected to an installation that we have installed.

RCD failing to trip when the appliance is running, and the RCD test button is operated, could be an indication that the appliance is affecting the RCD. This is explained in Chapter 12, 13 and Chapter 30. The Electrician is responsible, not the Technical committee, to make the decision on which device is appropriate for the installation.This information should be held on record, with other design criteria and the Installation Test Certificate for the premises. This will be required in the event of claims for negligence (Public liability insurance). Some equipment will have DC leakage current by the nature of design, other equipment may produce DC currents during fault conditions, dictated by the construction of the equipment.

If equipment contains Power Electronic Converter Systems (PECS), more commonly known as inverters or VSDs, BS 62477-1 Safety requirements for power electronic converter systems and equipment sets out the requirements and Annex H provides guidelines for RCD compatibility. Manufacturers must define the safety requirements clearly for suitable RCDs. If this information cannot be obtained, a Type B RCD should be installed to cover the worst-case scenario. 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.Type B devices are also suitable for Type AC, Type A and Type F applications. How do I test the different Types of RCD? 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. There's never going to be a perfect solution but there does need to be a less complex solution than there is. Domestic properties with modern equipment and appliances, such as LED lighting, induction hobs, IT equipment and electric vehicle charging equipment. In your own words - It is not appropriate electrotechnical language, its generic and anyone following that as a lead will not carry out an appropriate assessment.