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| phil-news-nospam@ipal.net wrote:
> On Thu, 28 Feb 2008 12:11:16 -0600 bud-- <remove.budnews@isp.com> wrote:
>
> | http://www.mikeholt.com/files/PDF/L...sion_May051.pdf
> | has an illustration of a surge coming in on a cable service (pdf page
> | 40). The problem is the 'ground' wire from cable entry block to power
> | service is too long allowing a damaging voltage between cable and power
> | wires. A power service suppressor would do nothing to solve the problem.
> |
> | Cable, phone, ... other entry protectors need to protect to ground and
> | have short 'ground' wires to the earth conductor at the power service.
> | Otherwise the guide says "the only effective way of protecting the
> | equipment is to use a multiport [plug-in] protector". A N-G bond in the
> | power service also helps limit the voltage difference, particularly if a
> | power service surge suppressor is not used.
>
> If you do not have the proper common entrance for all services in one place,
> then the effectiveness of the surge protector power strip will be reduced.
> It's still better to have one than not. But it is no replacement for having
> the correct entry protection, which includes cable, phone, and power coming
> in at the same location and grounded together so voltage differences between
> these types of wiring are eliminated (at least with respect to surges coming
> in from outside on the wire).
..
A lot of houses have signal entrances too distant from power services.
It is better to have a good "single point ground". But everything I have
read indicates multiport plug-in suppressors with high ratings will
provide protection for almost everything but a direct lightning strike
to a house. The IEEE guide has an illustration of a multiport suppressor
protecting when a cable entry is too far from the power service. The
impedance to surges of the wiring inside the house greatly limits the
current, and hence energy, available at a plug-in suppressor.
--
bud--
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