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Article #114Re: is third transformer hole an earth?
From: Dave Plowman (News)
Date: Mon, 10 Nov 2008 00:26
Date: Mon, 10 Nov 2008 00:26
23 lines
2749 bytes
2749 bytes
In article <EFJRk.52823$vm.21202@newsfe08.ams2>,
Arfa Daily <arfa.daily@ntlworld.com> wrote:
> Well, the cable itself may be rated to 32 amps, and the breaker may be
> either 32 amps or 30 amps in an older installation, but never-the-less,
> this type of installation has always been known generically as a '30
> amp ring main circuit' and is generally accepted as being safely rated
> to 30 amps to include all ages of installation.
Dates from the days of rewirable fuses were it was a nice round figure.
But with those you could comfortably exceed 30 amps if the load was
imposed gently. MCBs react rather quicker so it's now 32 amps.
It's actually quite tricky to work out the loading in various parts of the
ring since there are so many variables - the lengths and how it is run,
ventilation wise. As well as where the load is actually taken. It's
basically a bit of a bodge - but a very satisfactory one for today's
lifestyle despite being some 60 years old in conception.
--
*I'm pretty sure that sex is better than logic, but I can't prove it.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
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X-Google-Thread: 1131b0,8ae7935e94fea1ee X-Google-Thread: faa3c,8ae7935e94fea1ee X-Google-Attributes: gid1131b0,gidfaa3c,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news1.google.com!news1.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local02.nntp.dca.giganews.com!nntp.pipex.net!news.pipex.net.POSTED!not-for-mail NNTP-Posting-Date: Sun, 09 Nov 2008 18:28:44 -0600 From: "Dave Plowman (News)" <dave@davenoise.co.uk> Subject: Re: is third transformer hole an earth? Newsgroups: sci.electronics.repair,24hoursupport.helpdesk Date: Mon, 10 Nov 2008 00:26:24 +0000 (GMT) Message-ID: <4ffbc74aaedave@davenoise.co.uk> References: <gf43nr$fiv$1@registered.motzarella.org> <5JkRk.106$Cn3.92@newsfe20.iad> <slrnghc3uf.bnl.catwheezel@ID-107770.user.individual.net> <v6FRk.32439$mr4.6073@newsfe19.ams2> <4ffba77383dave@davenoise.co.uk> <EFJRk.52823$vm.21202@newsfe08.ams2> User-Agent: Pluto/3.04e (RISC-OS/4.39) NewsHound/v1.50-32 Organization: None Lines: 23 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 79.73.81.206 X-Trace: sv3-DIzb+b9DmlUFbZq28KbfZlBGb07wEUYat0ieRun8FHdlhJ2cATdtkoKi2rgGqjFoVzLAtPbKSol+Db9!l8SVuxiaOYmyIAffnFw4s2QQ3WoEwyg1PPxVwb/Xf3wuyFmiHJyACRuAnY1AWNZZbGkURO6OQSBr!5NWJm/Xm X-Complaints-To: abuse@dsl.pipex.net X-DMCA-Complaints-To: abuse@dsl.pipex.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.39