Re: Equipotential bonding

In article <EtWdnYpt9rRyfMDUnZ2dnUVZ8sTinZ2d@xxxxxx>,
beamends <sales@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Tue, 30 Dec 2008 12:56:41 +0000, Lester Caine wrote:
So having a clean 0V reference makes perfect sense to me, with a
nice quiet +24V supply in my case to take load off the DCC feeds.

0V is a tested connection to physical earth, it has a specific meaning
when wiring panels, transformers etc.

Maybe that's what 0V means in the US when talking about mains wiring.
But in this (UK) group and in the context of model trains, it doesn't
mean anything of the kind.

0V in this context just means the nominal baseline against which other
voltages (in the low voltage system) are quoted. It may or may not be
earthed inside the mains power supply, but there is no need to earth
it separately.

Indeed in some systems with multiple power supply rails, a rail other
than the nominal 0V may be earthed inside the PSU although I would
expect most model railway systems to avoid that - since in such a
setup a naive user who earths the 0V output PSU terminal effectively
shorts out the PSU.

(Assuming of course you're using reputable equipment!)

--
Ian Jackson personal email: <ijackson@xxxxxxxxxxxxxxxxxxxxxx>
These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson/
PGP2 key 1024R/0x23f5addb, fingerprint 5906F687 BD03ACAD 0D8E602E FCF37657
.

Relevant Pages

  • Laptop PSUs - bit OT - sorry
    ... Investigated further and on a couple of others and found anything up to 120v AC from either leg of the DC connector to earth (even the PSU with an IEC 'kettle connector' didn't have the earth pin connected to anything) and all measurements everywhere were up in the Megohms. ...
    (uk.tech.broadcast)
  • Re: Belkin fried in storm?
    ... That was the only other device plugged in, the router was being used purely as a WiFi device, no ethernet connections at all, so as you say it tried to find a route to earth via the PSU. ... His ISP are sending him a new router FOC anyway. ... Please replace invalid and invalid with gmx and net to reply. ...
    (uk.telecom.broadband)
  • Re: Strange electric shock?
    ... I measured the voltage between the earth rod and the UHF plug shell, ... PSU, also off. ... Sounds like a bad earth on the mains side of the PSU and a link between the ...
    (uk.radio.amateur)
  • Re: Equipotential bonding
    ... 0V is a tested connection to physical earth, ... Maybe that's what 0V means in the US when talking about mains wiring. ... a naive user who earths the 0V output PSU terminal effectively shorts ...
    (uk.rec.models.rail)
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