[chbot] OT: Low profile RCB

[Volker Kuhlmann]

On Sun 13 Jul 2014 23:11:03 NZST +1200, Marshland Engineering wrote:

> Coming from South Africa - every (we legal) house had an RCD in line  
> the incoming mains. Ie every circuit was protected. I've did this in  
> our house we built 14 years ago an never had a problem. Would do the  
> same again.

Not legal in New Zealand. It's also a really bad idea to have a single
RCD for your whole house! The limit here may be 3 breakers per RCD now.
I bet it's partially to stop unscrupulous tradespeople from increasing
profits by creating substandard installations (a single RCD for a house
is substandard as far as I am concerned, no matter the law).

> If fridges and freezers start to trip it - get rid of them and get
> new.

Yes. Because in a house meeting current requirements they must have an
RCD and therefore would no longer work.

But that system fails with heaters, because heating elements have a
natural earth leakage when hot. I last noticed this when I tried to get
a heater an RCD, but each of the 1.5kW elements alone would trip the
30mA RCD within 45s when cold. All elements were out of the box and
unused. That's why large heaters with fixed installation (kitchen
stoves, hot water elements, etc) don't need an RCD. It wouldn't work
anyway. All of these appliances must still be earthed, shouldn't be
opened and have fixed wiring, so an RCD would give little extra
protection anyway.

Volker

-- 
Volker Kuhlmann
http://volker.top.geek.nz/	Please do not CC list postings to me.