[rescue] 48 VDC v -48 VDC...jeez!

[Kevin Loch]

George Adkins wrote:
>>Can anyone simply explain why egSun uses -48vdc and if anyone else uses
>>+48vdc?
>>
>>Can I assume NOT everyone in telecom uses -48vdc?
>>Is most telecom -48vdc ?
>>
> 
> AFAIK, all telco-style DC equipment is -48V DC.  I have never seen anything 
> called +48VDC except for UPS Batteries.
> 
> 

The reason for using -48dc is chemical.  High positive DC voltages
on certain metals (like copper) tend to oxidize rapidly.

KL