[Gllug] OT: Merging UPS outputs

Alain Williams addw at phcomp.co.uk
Sun Aug 21 13:51:58 UTC 2005


On Sun, Aug 21, 2005 at 02:42:28PM +0100, Liam Smit wrote:

> >    So are you suggesting that every building should be wired with sockets
> > that look pretty and have no earth, sufficient for every need, plus sockets
> > which do have an earth, sufficient for every need, including future
> > proofing? Buildings are already supposed to have sufficient outlets without
> > the need for trailing sockets.
> 
> I didn't suggest anything of the sort. In SA we have 3 pin plugs and
> circuit breakers. So all the small appliances (e.g. cell phone
> charges) with two pin plugs get plugged into adaptors and larger
> appliances (e.g. TVs) have their plugs cut off and 3 pin plugs fitted.

Aaargh! So you buy something & immediately modify it!
Many people are incapable of wiring plugs.
This sounds like a recipe for disaster - I sometimes worry about the number
of plugs (even from shops) that I have found to be incorrectly wired:

* Earth & return wires mixed up
* Cord grip tightened on the electrical inner wires, not the outer sleeving
* Wrong fuse

Sooner or later someone gets hurt with lots of things like this around.

> >    AC mains often tends to make your muscles throw you clear, we were told
> > to test any suspicious objects using the back of our hand if there is no
> > safe way, because it may be painful but you will be thrown clear. If it is
> > live DC your muscles are even more likely to tense and hang on, less likely
> > to throw you clear.
> 
> Well AC tends not to hold you like DC does. Which is why electric
> fences gave you a DC jolt and then stop , then they give you a bigger
> DC jolt and then stop.

Just to be pedantic: 230V AC is 230V RMS (Root Mean Square), in fact the
peaks are 325V, but it then passes through zero 100 times/second.

-- 
Alain Williams
Parliament Hill Computers Ltd.
Linux Consultant - Mail systems, Web sites, Networking, Programmer, IT Lecturer.
+44 (0) 787 668 0256  http://www.phcomp.co.uk/

#include <std_disclaimer.h>
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