gkenyon:whjohnson:
I'll sometimes run a 1.00mm from a B6A rather than a 2.5mm for a FCU, especially when room is tight and the load demands only a 3A fuse at the destination end.
No point in running a bigger cable to provide capacity which most likely will never be used.Regulation 524.1 (via Table 52.3) requires a minimum 1.5 mm2 for power circuits (i.e. not lighting circuits or auxiliary/control circuits) in sheathed cable. Yes, a reduction for a specific appliance is permitted in Table 52.3, but that's only in flex to the appliance itself, not from the mcb to the appliance.
Hi Graham, it could be argued that "an alarm or something similar" would be classed as a "signalling and control circuit", and the minimum CSA of 0.5mm2, or even possibly 0.1mm2 since most alarms are electronic.
Andy has commented about table 52.3 in this old thread https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=54291&STARTPAGE=1&FTVAR_FORUMVIEWTMP=Linear
gkenyon:whjohnson:
I'll sometimes run a 1.00mm from a B6A rather than a 2.5mm for a FCU, especially when room is tight and the load demands only a 3A fuse at the destination end.
No point in running a bigger cable to provide capacity which most likely will never be used.Regulation 524.1 (via Table 52.3) requires a minimum 1.5 mm2 for power circuits (i.e. not lighting circuits or auxiliary/control circuits) in sheathed cable. Yes, a reduction for a specific appliance is permitted in Table 52.3, but that's only in flex to the appliance itself, not from the mcb to the appliance.
Hi Graham, it could be argued that "an alarm or something similar" would be classed as a "signalling and control circuit", and the minimum CSA of 0.5mm2, or even possibly 0.1mm2 since most alarms are electronic.
Andy has commented about table 52.3 in this old thread https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=54291&STARTPAGE=1&FTVAR_FORUMVIEWTMP=Linear
We're about to take you to the IET registration website. Don't worry though, you'll be sent straight back to the community after completing the registration.
Continue to the IET registration site