Re: Phoneline Surge protectors
Charles Scott (cscott@freeway.net)
Mon, 16 Sep 1996 13:05:58 -0400 (EDT)
Matt:
Actually, the ONLY good way to protect your equipment IS to tie all
your grounds together at one point. This is called (rather obviously) a
"single point ground window". The intent is to prevent current from going
through your equipment and is most important whenever you might be
suseptable to nearby or direct lightning.
The way it works is that all connections to your equipment come across
a "ground window". This is in reality some adequate conductor, often a
copper plate, to which the power line and phone line surge arresters are
bonded. It's also important to bring any serial, printer or other I/O
lines which go to other equipment, across that same window. If all of
your computer equipment, including any terminals or other devices have
their signal and power lines come back through that ground window, you
can survive a direct lightning stike on your facility without loosing any
equipment. Also, if you have your UPS on the equipment side of the
ground window, your system may even continue to function without any
interruptions during such a strike (although you may loose outside
connectivity).
Think of it this way. Electricity needs a complete circuit. If your
equipment is in the middle of a completed circuit (sitting between the phone
lines and the power lines), then the current will be going through it. If
your equipment is hanging on the end of a ground window, and nothing is
connected from your equipment to anywhere but the ground window, then you
have no such current.
Needless to say, there's a lot more to it that this, but it's the basic
idea. This is the approach which broadcast and communications facilities
use to protect their equipment, and believe me, those towers really get
hit!
Chuck
On Mon, 16 Sep 1996, Matthew S. Crocker wrote:
> > I'm a big fan of Panamax.
> > If you get the Panamax TowerMax and the Co4x4 ( dont quote me on that
> > number. the 4x4 is an 8 jack RJ11 surge supressor 4 lines in 4 lines out
> > ) you can also get the CO-T1 ( again, dont quote me on that ) that protect
> > two T1 lines. All of these have Panamax's $5 Million dollar lifetime
> > equipment protection warranty. Unfortunatly it gets Bulky real quick but
> > I haven't found a more dense solution yet.
>
> Remember,
>
> Surge Suppresors mean nothing if they are not installed properly.
> Remember to ground them properly. Also don't tie all your grounds
> together, A surge could come in through the phone line, hit the surge
> protector which will channel it to ground. The surge will then go
> through the ground wire and hit the equipment in the power supply.
>
> -Matt
>