ZFS regimen: scrub, scrub, scrub and scrub again.

[Julian H. Stacey]

Steven Chamberlain wrote:
> On 22/01/13 19:28, Chris Rees wrote:
> > On 22 January 2013 19:01, Zaphod Beeblebrox <zbeeble at gmail.com> wrote:
> >> On Tue, Jan 22, 2013 at 4:11 AM, Adam Nowacki <nowakpl at platinum.linux.pl>wrote:
> >>> This is what was in my wall: http://tepeserwery.pl/DSC_0178.JPG
> >>>
> >> Damn, son.  That socket is obviously not rated for whatever you used it
> >> for.
> > 
> > That is a standard European socket, which are normally rated at 13A.

Re. Eurpean sockets:

I doubt 13 Amps (though I don't know Polish system, possible I suppose)
British square pin are 13 Amp. 
German continetal etc are not.

This (Polish?) socket looks similar to French
French are (marginaly better than German & Austrian & North
Italian/South Tyrol)

Continetal wiring standards I've seen are shamefuly dangerous
comparedto British (which are to better standard, cost more per
equipment & more work to install)

In a German rental flat here, one of several hundred in a big, not cheap complex
built in Munich in 1985, there are just 16 A & 10 A trip fuses.  
   I suspect a lot is spur wired, not ring main. Certainly it's
   combined lighting & floor power on 1 fuse per several rooms.  No
   Earth trip, though I'm told it should have one (but I wont commit
   myself if it Should by law, as I've not myself researched German
   law/ standards on that)

   Naked socket with unscreened holes & no switch, between the 
   2 hand basins in the bathroom, inches apart from the basins.

   a 2nd socket for clothes washing machine in bathroom.

   a light switch switch, not ceiling pull cord in the wall.

All quite normal by German & continental standards, all appalling to
a British electrician.

What is shown in http://tepeserwery.pl/DSC_0178.JPG I suppose is
Polish, never been there, but looks just like a French style socklet
(same material used as German & Austrian & very North Italian (=Sued
Tyrol), But the French (& I see Poles) at least achieve the possibility
of differentiating neutral from live, by virtue of the offset earth
pin.

These (type of) sockets are rubbish compared with British 13A sockets.
Reasons:
	No chance of a switch (cheap British one dont, decent ones do).

	Big reason: see the tiny claws (more visible on left) ?
	Leftmost screw pushes tthem sideways into the wall. That's
	all that holds socket in wall, 2 claws; after a while they
	work loose. If you've got a vacuum cleaner or kettle plugged
	in (that needs firm contact for all the current, to avoid
	getting hot), there's a heavy outward force out of wall
	when unplugging. (I always use one hand on plastic to help
	it Stay in wall, whith other hand on plug to pull out.

	Another reason: all that naked metal when the cover is off
	(a British socket is a lot more covered, much lower chance
	of electrocution at 230V in Europe)

	Another reason: UK plugs also have variable 2/3/5/13 amp
	fuses in plugs.  Continetal sockets supply up to room circuit 
	fuse rating, a lot more than many appliance cables
	can take.

	Another reason: Polarised Live & Neutral (well at least French
	& Poles achieve that, Germans Austrians & North Tyrol fail.
	
	They like crap sockets on the continent, as seen in picture
	'cos you just a use combi circular saw with drill in the
	widdle, to quickly pilot a hole, then sink bigger circular hole in
	wall. & then bung in a cheap circular plastic cylinder (that
	the metal claws eat into & scratch out of over the years)

	In Britain, you have to hack out a square hole (a lot more
	work, then put in a more expensive galvanised steel square
	cavity box, then bang in several masonry nails sideways
	to hold the steel box inplace, then screw in the more
	expensive better socket, with proper metal thread screws
	into screwed holes that make a good grip.

	The plastic cover on British sockets is much thicker & stronger

In Munich, Schiller Str (main computer/ PC street) sold
British polarised square plugs & sockets as high quality luxury
equipment at several times UK prices.

Much continental wiring is Sub Standard & would be condemned under
British (ex IEE as was) wiring regs.

British plugs are admittedly an absolute swine if you walk on them
accidentally bare foot, & clunkier in a laptop case, but the plugs
& sockets are _Much_ better, What cost a life or a burnt building.  ?


> Maybe they don't work very well with paint splattered inside them.
> 
> My guess is the paint was slightly metallic or conductive, so a current
> was flowing between one of the screw terminals on the right, and the
> bolt in the mounting bracket (which is probably earthed).
> 
> The socket may have been supplying a lower voltage as a result,

The voltage would only drop sufficient to count as brown out
if there was horrendous heat evolved inside plug / socket combo.
These crappy continetal plastic covers suffer from heat easily,
but you'd need very little voltage drop to cause the browning seen.

> hence
> the equipment suffering brownouts.  (But it seems the UPS wasn't
> sensitive enough to this?)
> 
> Ideally a circuit breaker would have tripped before anything got hot
> enough to melt, but in this case the heat in the right-hand-side rail
> (in a wall, with no air circulation) became enough to discolour the
> plastic.  I think it's lucky it didn't cause a fire.
> 
> In the UK most house/office socket circuits are supposed to be protected
> by an RCD, which are extremely sensitive to fault currents like this
> flowing to earth.

Probably just an HR high resistance bad contact causing heat, I've
seen so many loose continetal sockets, relatively few UK 13A ones
by contrast.

When mean or shops closed, I remove socket & file the holes (after
fuse off :-) Fine emery (black sand) paper is good to ploish plug
contacts.  Ive know many public in Britain & Germany use plugs for
many decades, till pins are really dirty, & they never think to
polish plus pins.  So easy to do, even if it takes an electrician
to remove & replace or clean (or tighten springs in) a socket.

PS  2 pin multi way continental adapters are also crap: Insert 2
pin plug fully in an adapter, & you can feel the metal contact is
sometimes off, or often almost off, ready to be high resistance or
fail 'cos its gone too deep, 'cos too much of the shaft is plastic,
& not enough metal along the tip. Can occasionaly be cause of eg laptops
& electric toothbrushes, & razors not charging.


> If there are any more sockets in that room/building I would definitely
> check all of them!  (Carefully, with the supply disconnected, of
> course).  Or an insulation/leakage test of the circuit by an electrician
> would have detected this.


> 
> > checksum errors on multiple
> > disks, all fixed thanks to raidz2.
> 
> Well, that's some relief :)
> 
> Regards,
> -- 
> Steven Chamberlain
> steven at pyro.eu.org


Cheers,
Julian
-- 
Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich http://berklix.com
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