Square D KQ B 32 AMP MCB 240 v BS60898 10B132 A 10Ka CIRCUIT BREAKER

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That's quite a large difference and hence the reason why the national standards in other European countries do not include Zs tables, only the formula is provided. Circuit-breakers to BS EN 60898-1 may look identical to those complying with BS EN 60947-2 but they are not necessarily inter-changeable. However when I look at table 41.1 it is stating that if Uo is 240Vac the permissible disconnection time is only 0.2 seconds. Circuit-breakers are primary circuit protective devices. They are not intended for frequent switching of loads. Infrequent switching of cbs on load is admissible for the purposes of isolation or emergency switching. 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.

When testing is carried out at an ambient temperature which is less or greater than 10 oC, the correction factors listed in Table B8 of the OSG or Table A6 of GN 3 should be applied to the maximum Z s values listed. A cb designed for Pollution Level 2 conditions would not be suitable for harsh outdoor or humid applications that require Pollution Level 3. But it is not really a sudden step in risk between 230v and 231, more of a gentle rise in risk from quite safe at about 50V to really very bad for you by perhaps 1500V , from which 2 handy values have been converted into safe times for the table. Maximum earth fault loop impedance (Z s) values are tabulated in BS 7671 for cbs to BS EN 60898-1 but the maximum Z s values for cbs to BS EN 60947-2 need to be obtained from the manufacturer. Where manufacturers’ values of Z s for MCBs are used, they will often recommend multiplying the measured value of Z s by a correction factor, to correct for ambient temperature. For example, Schneider, recommend using a factor of 0.8,From Table B6 of the OSG, the maximum measured Z s value is1.75 Ω at an ambient temperature of 10 oC. 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. IEC 60898-1:2015 applies to a.c. air-break circuit-breakers for operation at 50 Hz, 60 Hz or 50/60 Hz, having a rated voltage not exceeding 440 V (between phases), a rated current not exceeding 125 A and a rated short-circuit capacity not exceeding 25 000 A. This second edition cancels and replaces the first edition published in 2002, Amendment 1:2002 and Amendment 2:2003. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: It is convenient when the performance of a cb meets the requirements of both standards and is therefore suitable for residential, industrial and commercial installations.

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. The most suitable solution is for MCBs that are certified by both IEC standards since their performance meets requirements for use in residential installations and is high enough for use in industry and infrastructure applications. Due to the high level of protection performance of these CBs, they should be used at least for the incoming electrical switchboards in buildings applications. Appliance for MCB’s to standards in different applications of useFor example, the BS EN 60898-1 standard describes B, C and D operating curves with ratio to rated current. But the BS EN 60947-2 standard prescribes an instantaneous tripping release which may be provided with a plus or minus 20% tolerance and adjustable as illustrated in Fig. 1. For this reason, manufacturers provide additional curves K, Z and MA to the B, C and D curves. How comes BS 88 and bs1361 fuses have two tables for 0.4s and 5S but 60898 fuses have one which covers both.