[AusNOG] Rack Studs - AWESOME

[Peter J. Cherny]

On 01/02/14 16:02, Tim Sheahan wrote:
> For the immediate interest of those here, would anyone care to amplify a
> little further on basic best practices?

Rather than be a grumpy (grey) engineer I'd better try to be 
constructive <g>

A good starting point is 
http://www.commsalliance.com.au/__data/assets/pdf_file/0017/39203/S009_2013.pdf
and AS/NZS 3000 Wiring Rules, sadly behind a pay-wall.

The missing link in both the literature and standards is some background
as to why we need to understand wiring schemes.
The issues relate to
   safety i.e. protective/safety earthing
   earth differential potential - e.g. sparks from signal earths
   consequences of earth loop current - common-mode mains noise 
injection and induction
   RF earthing
   building and facility wide earthing schemes

Nearly all of the above are mitigated by a mixture of
   solid bonding of chassis/racks to a mass earth
   radial bonding to a nominal building equi-potential point
   sacrificial earth paths to force loop currents away from signal 
earths/shields
   sensible use of fiber interconnect where copper could be compromised
   detailed understanding of safety earthing and the overlay telecomms 
earthing

I'm somewhat biased away from the vanilla data-center towards the needs 
of the AV world,
(think a few PB of disc, SDI, MADI, 1G/10G links, SAS), but we're all 
using the same tech.