[chbot] OT: Low profile RCB

[Volker Kuhlmann]

On Mon 14 Jul 2014 12:09:26 NZST +1200, Charles Manning wrote:

> Why?

Leakage faults are much more common than shorts. Then it's late at
night, your whole house goes dark and you're scrambling for the
candles... It's a stupid system design.

> Sure it is better to have multiple RCDs and reduced "fan-out", but
> surely having one RCD is supremely better than having none.

Sure, but the issue is between one RCD and multiple RCDs. Here in NZ the
requirement for "an RCD" was there first. Then it changed to "1 RCD per
N breakers max". I say (but don't know) that was to stop tradespeople
installing absolute minimum for the unsuspecting instead of providing
something intelligent. So lift the minimum.

> Seems to work in South Africa when I lived there, but maybe the laws
> of physics were different under apartheid.

My own observations are clear. The heater + elements (3x 2kW, I was
wrong before) were manufactured in Europe. Finland, to be precise (there
goes the national joke... ;-) ) There is nothing wrong with the heater.
The heater metal and the elements are earthed, I feel quite safe without
RCD with that.

The rules here in NZ are that fixed-wired heating appliances need no RCD
(or so I was told by the sparky when I had my switchboard replaced some
years back). Why do you think that is? It's not a left-out-by-accident,
it's a deliberate exception.

Volker

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