Assemblies such as distribution boards are validated with specific circuit-breakers installed and these cbs are usually from the same manufacturer as the distribution board. Where cbs made by a different manufacturer are to be installed, verification will have to be undertaken by the manufacturer of the distribution board to BS EN 61439-2 or BS EN 61439-3. Fitting unverified devices will invalidate any verification and the warranty. I can say is that mix-ups of standards happen. The ideal way to avoid them is with tightly worded and highly enforced national regulations. And, for prescribers to specify what CBs will be used for and then confirm that the standard governs that usage. Private installation, TNCS earthing system where the main transformers taps are set to give phase/phase voltage (U) 416Vac RMS on the secondary side.

BS EN 60898-1:2019 Electrical accessories. Circuit-breakers for overcurrent protection for household and similar installations Circuit-breakers for a.c. operation I work for the utility in South Africa and am researching the use of MCB’s at the PUC between the utility and an IPP.NAPIT’s Don Holmes looks at the two different circuit-breaker standards, and provides clarification on the differences between them. No. Consequences can be serious if residential CBs are used instead of industrial ones. An MCB designed for indoor, pollution degree 2 conditions would be inadequate for harsh, outdoor applications that require pollution degree 3. One of the more common types of BS 3871 circuit breaker found on installations is the Crabtree C50 which was produced in single phase and 3 phase versions. These are all Type 2 circuit breakers and their fault current rating can be determined by the infill paint in the operating handle. White paint infill indicates a 3kA rating and yellow paint indicates a 4.5kA rating. BS 3871 circuit breakers were also manufactured as Type 4. Generic data cannot be used for Type 4 circuit breakers and the manufacturer’s data must be used to calculate maximum values of earth loop impedance. The more common forms of Type 4 are listed in the following tables, together with their maximum values of Z s, for 0.4s and 5s disconnection times. FEDERAL

Whoops, you don’t have access to that! Please register with the IET to join the community and access this area. When Z s tests are carried out at an ambient temperature of 10°C, the conductors being tested may be assumed to be also at 10°C. This means that the tabulated maximum Z s values of Tables 41.2, 41.3 and 41.4 need to be adjusted accordingly. For a cable having thermoplastic insulation with a maximum permitted temperature of 70°C, this adjustment can be made by simply multiplying the maximum Z s values in the appropriate table by 0.8 (Appendix A2 of GN 3). But I’m still confused in case of MCBs that have 2 condition of breaking capacity depend on which IEC that MCB comforting to Where a more frequent switching is required, such as the switching on and off of banks of luminaires, the manufacturer’s instruction should be followed and preferably an alternative device should be selected.Are AC MCB’s able to be used for DC applications? If so, What is it about the Ac rated MCB’s that makes this possible? However if we perform the calculation using 230Vac will will get a reduced permissible Zs. This would seem to suggest to me that we could be failing Zs values that allow enough current to flow in the event of a fault to trip the fault protective device. Any installer who plans to substitute a different cb must obtain authority from the assembly manufacturer to do so in compliance with Regulation 536.4.203. Otherwise, responsibility for the testing and integrity of the compatibility between devices would be down to the contractor. When this is not carried out, there is a probability that, in the event of an accident, fire or other damage, the installer would be accountable under Health and Safety Legislation.

I a = current causing the automatic operation of the protective device within the time given in Table 41.1. Stroma Certification provides some guidance on values of earth loop impedance (Z s) for legacy circuit breakers. I am confused with two standards for the same breaker. Does it mean that the trip kA is different when the breaker is used for residential or non residential use? ICU and ICN. Also as i am new, how do i calculate my trip current ? Assuming the breaker is a 3 phase 230VAC, 63A. Dear Sahad, it is normal having MCCB certified as per 947 in commercial/small commercial buildings with MCB’s certified as per 898. And it is wrong to use MCB’s dedicated for domestic applications (60898) in industrial applications installations. No, your statement is not correct. MCB is a miniature circuit breaker and MCCB is a molded case circuit breaker. Difference is in the breaking technology and size.Many ABB fuses require more tripping current (Ia) to operate in 0.2 seconds compared to a 0.4 second trip.