BS 3871 , no good for isolation ????

[razz]

hello all , i work in a school that is full of the BS 3871 breakers , i`ve noted that in the H&S guide for safe isolation procedures says that the BS3871 circuit is not suitable for isolation , does anyone know why this is so , cos if i lock it off using the suitable lock , why is it now not suitable , hope this makes sense , cheers

 

[malcolmsanford]

The old BS 3871 was withdrawn in the early 90's and replaced with the BS 60898. I think what you are refering to is not isolation as in safe isolation for testing, but that the mcb can be used as a means of isolation from Table 53.2 in the BRB.

I can't remember for sure if the BS 3871 was suitable for isolation, but if anyone as a 16th edition handy they can tell us. The replacement MCB the BS 60898 though can be used for the purpose of isoaltion, emergency switching and functional switching

 

[nickblake]

if i remeber rightly the reason these do not comply is due to the gap in the contactors it needs to be a certain distance appart and the BS3871 does not , this breaker was replaced by the BSEN60898 which complies with the isolation and switching