Hi everyone.

I have recently done a PIR on a music school and the DB was a 3ph DB with BS3871 (brown crabtree mcbs)

2 of the circuits are 'protected' by BS4293 30A 30mA C50 rccbs. Live and neutral connected in to the device.

On first look I assumed they were rcbos just older style. They tripped out within the correct tripping time so just continued as if there was no problem!
I am now filling out the report and I need to fill out max zs for the devices and it seems that bs4293 are only rcds and do not protect against overcurrent/short circuit!

I am struggling to find anything online about this and its going to greatly affect my PIR so could do with a bit more info on these devices.


Is there anybody out there who has come across these and can clear this up for me please?

Also if they are just Rcds what the hec can they be replaced with?

Thanks in advance.

Russell

Are they the ones with two indicator buttons, one blue and one yellow and take up two modules width?

Regards

BOD

Appendix 1 in the 15th Edition lists BS 4293 as "Residual Current operated circuit breakers".

Regards

BOD

Appendix 1 in the 16th Edition lists BS 4293 : 1983 as "Specification for residual current-operated circuit-breakers".

Regards

BOD

Thanks for clearing this up!

much appreciated perspicacious,

glad someones on the ball!