Mains switch size

listermint

I've noticed on 2 friends new builds their mains switch is 100A but my brother says they should be 63A however he's out of the electrical game a few years now in facilities.

Is there a change in ESB supply or is the mains wrong on these new builds ?

17larsson

It could be a 100A isolator with the 63A MCB inside the ESB meter box at the side of the house which would be fine

2011

Are you talking about the rating of the switch or the fuse?

listermint

17larsson wrote: »

It could be a 100A isolator with the 63A MCB inside the ESB meter box at the side of the house which would be fine

That makes alot of sense actually. I know new installs have to have switch outside now.

Luckysasha

The switch outside is commonly referred to as a contractor switch. It’s rated at 100A. The LV fuses in the black box at the ESB trafo pole are 100A and then it’s 63A at the ESB cut out in your meter box for discrimination purposes

TheBully

The fuses in your black box at the traffo are 100amp, the esb fuse in your meter box is 80amp and your main incomer fuse in your fuse box should be 63amp

Jennehy

Above post incorrect if it’s a domestic setup, it’s an mcb in enclosure installed in meter cabinet and just a main switch in consumer unit.
This is a domestic setup.