MK 6 AMP TYPE 2 M6 MCB CIRCUIT BREAKER 240V LN 5906 BS 3871

Product Information

How accurate is the 3kA value, and is that subject to cut off characteristics from upstream devices So now we have the two important facts: voltage is measured between two points, and an AC voltage is an average over time. Section 536 is about ensuring (amongst other aspects) that the performance of devices for protection against faults and overloads are coordinated so that the effectiveness of the operation of individual items of equipment, under both normal and abnormal operating conditions, does not impair the safety or proper functioning of the installation. It includes, for example, the set of regulations that provides requirements for selectivity of protective devices for residual currents, overloads and short-circuits. Every item of equipment shall comply with the appropriate British or Harmonized Standard.’ For distribution boards, this is the BS EN 61439 series. Part 3 is a specific part of the BS EN 61439 suite and it includes requirements for Distribution Boards intended for use by ‘ordinary persons’.

The regulation in question (536.4.203) specifies requirements for integrating devices and components into low voltage assemblies to the BS EN 61439 series and the regulation highlights: The last bit is to ask ‘how do I calculate the voltage difference between two phases with some other phase angle?’ Clearly this is some function of the amplitude of the phases, and also a function of the phase angle between them. Simplify the question by stating that both phase A and phase W have the same phase to neutral RMS voltage V. Call the phase angle between these two phases T. The voltage between the phases is then given by V * 2 * sin(T/2). So for the 180 degree phase difference we get V * 2 * sin(180/2) = V *2Originally there would have been a graph like we still get for a fuse and I would not think they would comply with BS7671:2008 and will need replacing to comply. Not sure what I would code it as? I think Code 2 "(Requires improvement) This code is to be used to indicate that the observed deficiency requires action to remove potential danger. Make a graph of the difference between A and W, and you will find out that it is a sine wave with low amplitude. In fact, it is a law of mathematics that the sum or difference of two sine waves of the same frequency (but possibly different amplitudes or phases) is another sine wave of the same frequency, again with different frequency or phase. My only hope is now if someone has any brochures stored somewhere with let through tables/graphs. Otherwise I will be replacing them

Knowing the right type of device to install is essential to protect equipment in all types of buildings, as is reflected in the evolving guidance. When purchasing a consumer unit or distribution board, the manufacturer’s instructions will state which devices can be used in the unit – and don’t forget according to BS 7671 (regulation 510.3) there is an obligation on designers and installers to follow the manufacturer’s instructions when selecting and erecting equipment. Type 3 SPDs provide local protection for sensitive equipment. As these have a relatively low discharge capacity, they should always be installed in addition to a Type 1 or 2 device. The Cmin factor is applied to the voltage to earth (Uo), so if the voltage is 230 the calculation would be 230×0.95 = 218.5 volts. For this reason, regulation 536.4.203 states that ‘The relevant part of the BS EN 61439 series shall be applied to the integration of mechanical and electrical devices and components, e.g., circuit-breakers, control devices, busbars into an empty enclosure or existing low voltage assembly.’On a slightly more benign note, circuit-breakers are designed to run warm in normal conditions when carrying load current. The thermal performance of the assembly is considered in BS EN 61439 to ensure that the internal temperature is not excessive and the operation of protective devices is not impaired – when excessively warm for example, the thermal overload operating current of a device will reduce, potentially causing premature operation. Excessive temperatures may affect the control circuits of electronic equipment mounted in the enclosure.

The person introducing a modification/alteration becomes the original manufacturer with the corresponding obligations for that assembly. OK - I was assuming 90C/250C (ie XLPE insulation and K of circa 150) so you should be OK for 2.0mm2 and upwards - which should exclude a whole load of circuits from your assessment. I don't for one moment think we need to use 3000 A for 0.1 seconds in this case but if you did then the 300 becomes more like 1000, and the minimum cable size is probably 10mmsq.... MCB (Miniature Circuit Breaker ( BS 3871 ) is a mechanical device operate automatic operation designed to connect and disconnect the electrical circuit in the ordinary and extraordinary situation.Suitable for AC and DC voltage.It mean main function is to protected equipment or circuit from overload and short circuit.

BS 7671 18th Edition Maximum Zs

should be taken as soon as possible to improve the safety of the installation." would be appropriate but maybe your not talking about the LoadMaster so that implies with that breaker 2.5mm is not OK, but you are comfortably OK with all cables of 4mmsq up and larger. If devices from different manufacturers are used together, the venting characteristics may not be coordinated which could result in significant further damage to adjacent devices or other parts of the distribution board.

The regulation in question, 536.4.203, was introduced by BEAMA (the UK trade association for manufacturers of electrical equipment including switchgear) to warn designers and installers of the possible dangers of mixing devices from different product ranges or manufacturers in the same distribution board; mainly, but not exclusively, circuit-breakers. When installing a new final circuit for example, if there is spare space in a consumer unit and a circuit-breaker that appears to fit is to hand, it is tempting to use it. Another example is replacing a circuit-breaker with an RCBO to afford better protection for the user. Indeed as Mike mentioned 10ms gives a very large number (for 3kA and 10ms -->> energy let through is 90000). Virtually every building in the UK, regardless of use, will contain electrical devices and equipment, which are central to everyday living and convenience. However, transient over-voltages, also known as power surges, can seriously damage these pieces of equipment. Damaged equipment not only incurs the expense of repair or replacement but also further, long term costs such as lost data if storage devices are damaged. New Requirements

Before delving into the detail of this change, as ever it pays to start at the beginning – namely the Fundamental Principles of Part 1. WHY used square root 3 in calculation –> this is the answer,please read discussion on this forum : http://www.electrical-contractor.net/forums/ubbthreads.php/topics/129279/1_732_square_root_of_3_where_d.html