Why choose 120 volts?

Dave Larter dave at stayonline.com
Thu May 28 09:44:00 CDT 2009

I was referring to, when a 120v device is attached to the 5-15 end of
the cord. On the inside of these grounded devices I often find that the
neutral is tied to ground. So in the case of the c14 being connected to
a 240v PDU when I 120v device is connected it will ground one of the
load lines.  And yes, voltage will drop while current spikes, thus
tripping the breaker. 

-----Original Message-----
From: Pete Templin [mailto:petelists at templin.org] 
Sent: Thursday, May 28, 2009 10:39 AM
To: Dave Larter
Cc: nanog at nanog.org
Subject: Re: Why choose 120 volts?

Dave Larter wrote:
> Seems like if the c14 was connected to a 240v PDU the 5-15 would
> deliver 240v to the equipment, arc/pop tripping the breaker on the
> PDU as soon as it is connected killing power to everything on that
> PDU.  Or am I missing something?

If you plug a PDU into a service that's higher voltage than expected, 
why would the PDU circuit breaker trip?  That breaker is measuring 
current, AFAICT, though in the end it might be measuring power. 
Regardless, it isn't measuring voltage, because that isn't constant 
(it's AC, after all) and is likely to drop under a short circuit, not 
skyrocket like the current will.


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