>"Here we have a MEN (Main Earth Neutral) connection at the switchboard. Power
>circuit are also RCD protected"
Adrian,
From your description, it appears Australia's residential distribution uses a
240V single-phase secondary from the utility company to the home with ONE SIDE
of the 240V feeder bonded to an earth conductor at one point: the main
service/switchboard panel. This forms the basis of your neutral. Please
re-describe if this isn’t correct.
By contrast, U.S. residential service also uses a single-phase 240V
distribution, but with a tapped secondary from the utility transformer which
gives us 120V-0V-120V 180-deg. split-phase, where the 0V tap is used as a 120V
current-carrying neutral and is bonded to an earth conductor at the premise's
main distribution panel.
>"When the neutral breaks/opens you get the full effect of the electrical
>shock. All appliances here, as well as the wall outlet must be switched in the
>active."
In the U.S., we also switch only the active lead, never the neutral.
>"At least you should install a sw/brd RCD (residual current device ) aka ELCB
>to trip the active, if you do get on the end of a live chassis."
In older U.S. homes without a third-wire receptacle grounding conductor, it's
common to upgrade the branch circuit with a GFCI device (AKA your ELCB). This
solution can avoid a massive system rewiring. I recently rewired my daughter's
75-year-old home this way.
Paul, W9AC
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