alt.engineering.electrical

In that case, you need to put some relaying on your neutral leg of the
incoming power supply and do something around Zero Sequence protection.

H.
==========
In article <47bc216a$1_2@>,
"Samuel Chan" wrote:

> Usually I posted on news group, no reply is back. THANKS!
> The final circuits are protected by RCD. However, the main switchboard can't
> perform E/F protection. That is the problem, as if there is a earth fault in
> main riser (say busbar), the value is talking about below 50A. Main CB will
> not trip but a 50A flow continuous from one phase to earth as leakage>energy
> loss>thermal>voltage drop?
> Samuel Chan
>
>
> "Stuart" wrote in message
> news:4f74122daaSW_NOSPAM@...
> > In article <@>,
> > Tomi Holger Engdahl wrote:
> >
> >> "GFCI devices which protect equipment (not people) are allowed to trip
> >> as high as 30 mA of current. In Europe, the commonly used RCDs have
> >> trip currents of 10-300 mA."
> >
> > I have a 10mA trip protected socket on my electronic test bench and a 30mA
> > trip on the mains between the supply authority fuse and my consumer unit.
> >
> > I have never seen an RCCD with a trip higher than 30mA on sale in the UK
> > although earth leakage trips in industrial switchboards can be a lot
> > higher than this.
> >
> > --
> > Stuart Winsor
> >
> > From is valid but subject to change without notice if it gets spammed.
> >
> > For Barn dances and folk evenings in the Coventry and Warwickshire area
> > See: