Why choose 120 volts?

Matthew Moyle-Croft mmc at internode.com.au
Tue May 26 18:13:55 CDT 2009

Jay Hennigan wrote:

> Most of the rest of the world has 240v as conventional domestic power, 
> and most server rooms or datacenters supporting >2KVA single devices 
> have 208 or 240v available, so it makes sense for manufacturers of 
> high-power gear to save the money on copper and connectors and insist 
> on higher input voltages for full spec output.
We're all 230vac here in Oz (it's a compromise between our old 240v 
standard and the Euro 220v one).  In Oz we basically have a single style 
of outlet for AC for low amps and a couple of ones for higher amps.

The higher powered PSUs are much easier to deal with on that - everytime 
we get ready to commission a new router etc for the US or Japan we look 
in amazement at the endless list of NEMA plugs and voltage options and 
different kinds of APC power gear we need to do everything.   It kind of 
freaks me out - locking, not locking etc.  Admittedly I find the 
standard 2 pin US style power connector somewhat wobbly and scary - ours 
seems to lock in much better.  

Since we get the same gear as North America mostly almost all of it 
copes with 90v to 240v AC 50/60hz.   It's rare these days to find things 
without switching PSUs.  

It's worth noting that despite higher voltages here there aren't more 
deaths or injuries - but maybe it's because people take it more 
seriously.  Admittedly no one I know is nuts enough to use body parts 
for "liveness testing".


> Yes, it would be nice to be able to plug in your laptop charger, etc. 
> And the voltage on that charger is likely compatible with anything 
> from 100 to 240V.  Wiring a NEMA 5-15 with 208V is just wrong, 
> though.  I have an IEC male to NEMA 5-15 female pigtail (old-school 
> "monitor cord") with a big sticker saying "208V - Be very careful what 
> you plug in here" for just that purpose.
> -- 
> Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
> Impulse Internet Service  -  http://www.impulse.net/
> Your local telephone and internet company - 805 884-6323 - WB6RDV

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