Can I use Type 1 MCB

[seftonbarn]

I have a Crabtree Type SB6000 CU. It has a spare way with a redundant MCB Type 1 6A. I was hoping to use it for a small lighting circuit. Can someone of more experience than myself advise me if the Type 1 MCB could be used under BS7671 17th edition?

 

[MarkieSparkie]

Yes, you can use an existing BS3871 Type 1 MCB (2.7 to 4 In trip current in the conventional time 0.1 to 5s), which is roughly equivalent to BS EN 60898 Type B MCB (3 to 5 In). These older devices should not be specified for new installations, hence the reason they were removed from BS7671 over 10 years ago.

 

[seftonbarn]

Yes, you can use an existing BS3871 Type 1 MCB (2.7 to 4 In trip current in the conventional time 0.1 to 5s), which is roughly equivalent to BS EN 60898 Type B MCB (3 to 5 In). These older devices should not be specified for new installations, hence the reason they were removed from BS7671 over 10 years ago.

Thanks for this informative response. To help me still further why can they not be specified for new installations? And does this reason not also apply to a new circuit added to a current installation?

 

[telectrix]

they are not used anymore because we have progressed. same as cars don't have x ply tyres or rod brakes anymore. but by the same token you can add a new circuit to an existing installation if that circuit complies with disconnection times. only thing would be if the lighting circuit were in a special location , it would require RCD protection.