Date   : Tue, 01 Sep 2009 00:15:00 +0100
From   : dm.hunt@... (David Hunt)
Subject: Leccy @ Acorn World '09

> > Anyway, if it turns out that 30A is all we have to play with, then my
> original
> > grand plans
> >
> <http://www.acornworld.co.uk/prep/AcornWorld2009_Power+Sockets+WiringPlan.
> png>
> > will need need to be toned down a bit (as I think we'd have been looking
> at up
> > to 55 amps).
> >
> > So here's an alternative, less-ambitious proposal:
> >
> http://www.acornworld.co.uk/prep/AcornWorld2009_Power_Reduced_Sockets+Wiri
> ngPlan.png
> >
> > Would this still be pushing it? (I'm not an electrician so would welcome
> any
> > input). Bear in mind that across the other side of the room you'd have a
> > laptop, projector and PA.
> 
> What are you basing your calculations on? Current usage per socket?
> 
> I've just measured the consumption of a mono monitor & Atom using a
> cheap plug-in monitor (so take figures with a healthy margin of error)
> at 0.2A. Plugging a beeb in pushed it up to 0.3A. I can bring at least
> two of these plug-in monitoring devices, and I guess other people have
> such devices. I suspect if we keep an eye on total usage we'll be ok.

The power used by the device is a fraction of the peak demand when it is
initially powered (inrush current). For a (fully loaded) Beeb the current
pulse is 1.8A for 120ms dropping to 0.15A and for my Beeb Sony CRT monitor
it's around 5A for 850ms dropping to 1A. I think we will need to avoid a
situation where a lot of stuff gets turned on at the same time and if we're
looking at RCDs that people don't try and reset the trip with everything
still switched on, otherwise the current rush could trip the main breaker
for the room. I doubt if we'd be popular ;)

Dave