Xref: utzoo sci.electronics:3995 comp.dcom.modems:2597
Newsgroups: sci.electronics,comp.dcom.modems
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: lightning on the phone lines
Message-ID: <1988Oct6.172207.29294@utzoo.uucp>
Organization: U of Toronto Zoology
References: <4789@b-tech.UUCP>
Date: Thu, 6 Oct 88 17:22:07 GMT

In article <4789@b-tech.UUCP> zeeff@b-tech.UUCP (Jon Zeeff) writes:
>Having lost 3 modems in two lightning storms, I am suddenly interested 
>in surge suppressors for the phone lines.  I bought an inexpensive one 
>that appears to have a small glass tube running from each line to 
>ground.  The tubes look like large diodes, except that inside they 
>appear to have something like a resistor inside.  I beefed this up by 
>adding MOVs from each line to ground.  

This isn't necessarily a good idea.  Protecting phone lines is much
trickier than protecting power, because phone lines have to meet fairly
strict electrical specs or you will have trouble, either equipment failure
or nasty mail from the phone company.  For example, I trust your MOVs
are rated for a nice high voltage (ringing voltages are *not* low) and
have quite low leakage currents at normal voltages (so the phone company
doesn't conclude that there's an equipment fault somewhere)?  I would
not recommend adding components yourself unless you have checked specs
carefully and know what you're doing.
-- 
The meek can have the Earth;    |    Henry Spencer at U of Toronto Zoology
the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu