[Amps] Benefits of 3-phase power?

Karl-Arne Markström sm0aom at telia.com
Wed Nov 19 08:27:21 EST 2003


In Sweden at least 3-phase feed is used for all "drops" to domestic houses built on this side of WW I.
Inside the house, after the energy meter, the single-phase outlets are distributed over the 
phases to create a reasonably balanced load. 

Larger loads, like electric heating, stoves and large washing machines
are 3-phase (often delta-connection) from the beginning. 

The current electrical code in Sweden does not allow larger fusing than 16A for single-phase
outlets, and then only if the round CEE connector is used. 
This limits resistive single phase loads to about 3.5 kW.
For domestic applications, the usual fusing limit is 10A per outlet or group of outlets.
In older apartment houses where the individual energy meter is single-phase,
there might be exceptions, a 20A single-phase fixed connection (not pluggable) was earlier allowed
to enable a small electric stove to be used. 

This was sometimes used by apartment-dwelling QRO enthusiasts to run
4-1000A's on full ratings by connecting the PA power supply feed in parallel with the stove. 
Usually these hams were bachelors, so the risk of having the XYL turning on the stove and blowing the fuse 
in the middle of a pile-up was remote.

73/

Karl-Arne 
SM0AOM



----- Original Message ----- 
From: "Bill Turner" <wrt at dslextreme.com>
To: <amps at contesting.com>
Sent: Tuesday, November 18, 2003 5:43 PM
Subject: Re: [Amps] Benefits of 3-phase power?


> On Mon, 17 Nov 2003 18:46:50 -0800, "Bert Almemo"
> <balmemo at sympatico.ca> wrote:
> 
> >Some basic facts about 3 phase....  Most of the electric power in the world
> >is 3 phase.  The concept was originally conceived by Nikola Tesla and was
> >proven that 3 phase was far superior to single phase power.
> 
> _________________________________________________________
> 
> Nearly all of the cross-country transmission lines in the US are three
> phase.  Only when it gets down to the neighborhood level do they go to
> single phase.
> 
> As to three phase being "far superior" I'm not so sure, at least for
> home use at low to moderate power levels.  I've never been to Europe
> so I lack first hand information, but all the various power plugs I've
> seen for European home use (and there are LOTS of variations) were all
> single phase.  So how do they use three phase in houses in Europe?
> 
> --
> Bill, W6WRT
> 
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