-48 volt DC Question

[The Streets]

I know that most telco switch rooms run their equipment
from a common DC supply (at least in the US).

I understand the advantages of a common supply. But
what is the advantage of using a negative rather than
a positive supply voltage?

 

[Palindrome]

I know that most telco switch rooms run their equipment
from a common DC supply (at least in the US).

I understand the advantages of a common supply. But
what is the advantage of using a negative rather than
a positive supply voltage?

A Hamlet*:

Galvanic corrosion takes place on the anodic surface. With a positive
supply voltage, this means that the any part of the wiring with leakage
to the ground plane will corrode. With a negative supply voltage, the
ground plane will become pitted and corroded, in the presence of a
leakage path and an electrolye. This is often less of a problem as there
is usually far more of it to corrode..


*Wild stab in the dark...

 

[Rack]

Bet you'll find more 24v than 48v now.

A Hamlet*:

Galvanic corrosion takes place on the anodic surface. With a positive
supply voltage, this means that the any part of the wiring with leakage to
the ground plane will corrode. With a negative supply voltage, the ground
plane will become pitted and corroded, in the presence of a leakage path
and an electrolye. This is often less of a problem as there is usually far
more of it to corrode..


*Wild stab in the dark...