[c-nsp] Grounding your 6500's?

[Temkin, David]

Thanks.  And you're right about having two floating grounds - I saw a
small-ish phone switch get blown up about 5 times at a summer camp that
had the chassis of the switch grounded to it's own ground spike about
100' from the building ground spike (which was in turn connected to the
chassis as well through the electrical ground).  Every time there was a
lightning strike anywhere near by (this was on a mountain), poof -
blackened phone switch. 

> -----Original Message-----
> From: Matthew Crocker [mailto:matthew at crocker.com] 
> Sent: Thursday, August 12, 2004 9:49 AM
> To: Temkin, David
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Grounding your 6500's?
> 
> 
> Grounding everything is a 'Good Thing' (tm).  We generally 
> attach a ground to everything that comes with a ground lug 
> attachment point.  If  
> that means we need to ground the chassis, each power supply, 
> the rack.   
>   We have a main ground bus running along the top of our 
> racks.  We H-Tap that bus onto a grounding bar for each rack. 
> Equipment in the rack is grounded to the grounding bar.  
> Everything is grounded back to the main ground bus (Racks, 
> Conduits, AC & DC power systems, transformers, panels, 
> everything).  The grounding bus is attached to the ground 
> (duh) which is the a copper mesh buried outside.
> 
> I have seen installations, mostly by Lucent that have a 
> completely separate grounding system for the phone switch.  
> The power plant is grounded to the building ground per NEC 
> requirements. The switch/equipment is grounded to a ground 
> field outside using 3 sets of 400 MCM cable.  Talk about over 
> kill.  I think having two floating ground is a bad thing and 
> can cause ground loops.
> 
> -Matt
> 
> On Aug 12, 2004, at 9:26 AM, Temkin, David wrote:
> 
> > Cisco specifically states that you "must" ground 6500 
> chassis, both at 
> > the chassis and the power supply ground lugs (separate from 
> the AC (or
> > DC) ground plant).
> >
> > http://www.cisco.com/en/US/customer/products/hw/switches/ps708/
> > products_
> > installation_guide_chapter09186a008020e0a9.html#wp1028096
> >
> >
> > Does anyone actually do this?  Our director got a "horror 
> story" from 
> > someone else who didn't ground their 6500's and so we're 
> looking into 
> > it.  It seems pretty nuts to have to run separate ground 
> lines to each 
> > switch and I've never seen it in the field, but I'm just curious.
> >
> > -Dave
> >
> >
> >
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