Re: why ground an alarm panel.

[w_tom <w_tom1@xxxxxxxxxxx>]

  The post in that other newsgroup was about grounding for
human safety.  OP was seriously (he implied) shocked when
connecting coax cables.  Every incoming utility wire must
connect to a common ground at the service entrance - for human
safety.  Therefore that discussion kept telling the original
poster to first verify or connect cable short to the same
earth ground used by telephone and AC electric.

  Furthermore, that service entrance ground serves a second
function - transistor safety.  Defined were other important
conditions such as 'less than 10 feet', no splices, no sharp
bends,  and wire separated from other non-earthing wires.

  The ground lug on Ademco is for human safety.  Alarm system
must connect to the same grounding system so that voltages
don't float.  Third prong on AC plug might also do this.

  Meanwhile, if grounding that alarm panel causes lightning
damage, then every utility does not connect *every* wire to
that single point earth ground.  Lightning damage directly
traceable to a human mistake. Every wire connected either
directly via hardwire (as suggested for cable in that other
discussion) or via a surge protector.

  Notice what a surge protector does.  Make that 'less than 10
foot' connection to a common earth ground when wire cannot
make that connection directly.   A protector that does not
connect from a wire short to earth is doing nothing effective
- a specific reference to plug-in protectors.

  Original poster was also encouraged to verify each surge
protector (such as one provided free by his telco) was also
connected to earth ground.  Single point earthing is THE surge
protection.  Wires or protector are nothing more than
connection to protection.

  The original poster has a human safety problem.  He was also
instructed to install / verify earthing so that transistor
protection was provided. Cable TV wire must bond to a common
ground for human safety.  And must connect short to earth
ground so that lightning does not find a destructive path to
earth via household appliances.  Two reasons (human and
transistor safety) why incoming utilities connect to a common
earth ground.

autonut843 wrote:
> Hi,
> I was just answering a post for someone on another group regarding how
> to ground a CATV line and it got me thinking.  Ademco panels all have a
> screw that they want tied to earth ground.  I've never seen a
> residential install that had that wire attached.  Why have it?  why do
> it?  why not do it?  Just curious.  Thanks