DC power versus AC power

Mon Dec 30 06:37:49 UTC 2002

It only takes 30ma to put your heart into atrial fibrillation. In the usa,
gfi's are set to trip at 5ma.

Normally 48VDC wouldn't be considered a 'lethal' voltage (I've talked to
telephone technicians who said they used to play a game in the CO by wiring
a handle to 90V ring voltage and seeing who could grab it for the longest
time), but you've got to consider the extreme cases where the working
environment may be wet or a worker could get exposed through open wounds,
puncture wounds or mucus membranes.

Under the right circumstances, nearly any voltage can be lethal.

Joe

On 12/29/02 5:40 PM, "Scott Granados" <scott at wworks.net> wrote:

> 
> Is 48V DC at the amps present normallyin switch rooms etc enough to cause
> electricucian?  I have seen bad things with wrenches dropped across
> batteries even 12 volt car batteries although in this case it was a large
> battery bank in a submarine but I was curious about the 48V sources in
> switch rooms.
> 
> 
> 
> ----- Original Message -----
> From: "David Lesher" <wb8foz at nrk.com>
> To: "nanog list" <nanog at merit.edu>
> Sent: Sunday, December 29, 2002 4:43 PM
> Subject: Re: DC power versus AC power
> 
> 
>> 
>> Unnamed Administration sources reported that Michael Painter said:
>>> 
>>> 
>>> 
>>>>> But, as Stephen already eluded to... Compared with an AC plant
> design, to
>>> me, one of the biggest drawbacks of a DC plant is safety  (I have had to
>>> kick a fellow worker away from the rack before). <<
>>> 
>>> What was the worker doing?  Is this 48 VDC?
>> 
>> Bet so.
>> 
>> And note, it's not just ISP's, of course. I heard that Sprint
>> PCS ha[s,d] a Dallas tech in critical condition and a dead switch
>> after a dropped wrench & resulting fire.
>> 
>> In the words of Phil Esterhaus:
>> 
>> Let's be careful out there....
>> 
>> 
>> 
>> 
>> 
>> --
>> A host is a host from coast to coast.................wb8foz at nrk.com
>> & no one will talk to a host that's close........[v].(301) 56-LINUX
>> Unless the host (that isn't close).........................pob 1433
>> is busy, hung or dead....................................20915-1433
>> 
> 