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

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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. So I2t is actually a function of the prospective fault current, and is either depicted graphically, or listed as spot values . For mcbs made to the IEC standards since 1999 or so this is a spec parameter, and guaranteed by design. for earlier devices it isn't 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 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....

is a nice number for rules of thumb , 1.6mm is nearly 1/16 of an inch and almost exactly the diameter of 16 standard wire gauge and 16 Birmingham sheet metal gauge, though not american wire, but AWG 14 is ~ 1.6mm dia. ) Additionally, any commercial, industrial, or public building that is supplied by overhead lines requires surge protection – so the majority of buildings will require surge protection. Residential properties will depend on use and occupancy levels. My only hope is now if someone has any brochures stored somewhere with let through tables/graphs. Otherwise I will be replacing them All SPDs work by diverting surge currents to earth to reduce the over-voltage to a level that will not damage the components of the system or equipment connected to it. There are three types of surge protection devices: Type 1In summary, can you mix devices in distribution boards (including consumer units)? Yes, you can. But you need to seek assurance from the manufacturer of the original assembly that the devices will be compatible, or conduct your own study to ensure the requirements are met. In the words of BEAMA, ‘The installer has responsibility to act “with due care”. If this is not done then there is a probability that, in the event of death, injury, fire or other damage, the installer would be accountable under Health and Safety legislation.’

so that implies with that breaker 2.5mm is not OK, but you are comfortably OK with all cables of 4mmsq up and larger.The reference calibration temperature for types B,Cor D shall be 30 'Cand for types 1, 2,3 and 4 shall be either In other words, adding together CE marked products from one manufacturer with another’s CE marked products does not necessarily equal a CE marked assembly which is compliant with BS EN 61439. This may also be true when mixing product ranges from the same manufacturer. This is reinforced in Note 1 of regulation 536.4.203 which states that ‘ The use of individual components complying with their respective product standards does not indicate their compatibility when installed with other components in a low voltage switchgear and controlgear assembly.’

Which leaves you with the lighting circuits - how far down the cable do you need to go, if the 3kA value is present at the DB, using 1.5mm2 conductors before you are safe again - not far I suspect. IF you put in the maximum breaking time of 10ms you will come up with a very large minimum cable requirement,and may well (incorrectly) conclude the cable is not protected. Of note here is that a protective device may conform to the appropriate product standard (e.g. BS EN 60898) and be UKCA marked. If the devices are from different manufacturers, they are likely to be designed differently and will perform differently – though both may comply with the appropriate safety requirements of BS EN 60898. 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. Now imagine another point in the system, also connected to phase A. If we measure the voltage at this point, we will get the exact same curve. Finally, try to measure the voltage between these two locations. If you look at each instant in time, the voltage _difference_ will be zero. The average of zero is still zero. Net result is that if you measure the voltage between two points, both phase A, you will get zero volts, as expected.Let through energy is a bit problematic for breakers - a fuse gets faster as the fault current rises, and tends towards a constant let- through energy (I squared r times time, but the resistance r is a fixed parameter of the fuse, as is the weight of metal to be raised to melting point to start it breaking) 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 Cor 40 O C , lhe purpose of the latter value being to avoid the necessity of de-rating thermaiiy sensitive circuit-

If you are looking for a reason to scrap the existing, then absence of that data is as good a reason as any K~ 145 for rubbers and 115 for PVC insulation , with certain assumptions about starting temperature.Indeed as Mike mentioned 10ms gives a very large number (for 3kA and 10ms -->> energy let through is 90000).