dana@gmu90x.UUCP (J Dana Eckart) (06/29/88)
As my investment in computer equipment increases, I become more and more concerned about how to protect it. Namely, what can I do to reduce the risk of damage via power and phone lines, particularly from lightning. As I understand it, there are basically two ways to protect the power source: line conditioning and/or uninterruptible power supplies. It would seem that UPS is best, but of course it can cost a great deal (upwards of $1000) whereas line conditioning can be had for much less (about $200). Given the prices, I would like to get by with just line conditioning. Will this provide satisfactory protection, even when hard disks are involved? What companies/models are best? How much protection against lightning strikes can I expect to get from either line conditioning or UPS? In the case of UPS, if commercial power goes out, is it possible to automatically signal the computer to do initiate system shutdown while battery power is still available? Likewise, there are protection boxes for telephone lines. Are these devices capable of making my modem safer from lightning strikes? As you can see, I just need some basic information. I would appreciate anything you can share. Thanks in advance. J Dana Eckart UUCP: ...!(gatech | pyrdc)!gmu90x!dana INTERNET: dana@gmu90x.gmu.edu SNAIL: P.O. Box 236/Fairfax, VA 22030-0236
gil@limbic.UUCP (Gil Kloepfer Jr.) (07/01/88)
In article <1187@gmu90x.UUCP> dana@gmu90x.UUCP (J Dana Eckart) writes: |>Namely, what can I do to |>reduce the risk of damage via power and phone lines, particularly |>from lightning. Correct me (those electrical engineers out there) if I'm wrong, but there's no real way of avoiding damage from lightning short of pulling the plug out of the wall socket and running things off batteries. I believe that there's always a chance of getting damage from lightning through the electric lines, even with a UPS or line conditioner. Damage through the phone lines is even more possible. The best protection is to pull the phone lines and power plugs on your machines. One point to note in particular -- those "surge protectors" are relatively useless against lightning strikes (contrary to what folks buy them for). They are for surges on the power lines induced by motors, etc. Lightning would fry the MOV (the device which provides the protection) up if it were strong enough to fry your machine. In short -- I would NEVER depend on a surge protector in a lightning storm. +------------------------------------+----------------------------------------+ | Gil Kloepfer, Jr. | Net-Address: | | ICUS Software Systems | {boulder,talcott}!icus!limbic!gil | | P.O. Box 1 | Voice-net: (516) 968-6860 | | Islip Terrace, New York 11752 | Othernet: gil@limbic.UUCP | +------------------------------------+----------------------------------------+
henry@utzoo.uucp (Henry Spencer) (07/08/88)
> ... there's > no real way of avoiding damage from lightning short of pulling the plug out > of the wall socket and running things off batteries... There's no positive way of avoiding damage from lightning. Period. Run your equipment off batteries and line your walls with wire mesh to form a Faraday cage, and if lightning feels like paying a visit, in it will come. This stuff has just punched through *kilometers* of air -- an awfully good insulator -- to reach the vicinity. Nothing you can do will stop it if it really wants to come in. Lightning rods and the like are based on giving it a more attractive place to go, not on stopping it from doing what it wants. If lightning is on your AC line, forget your computer and pray the bolt doesn't come looking for *you*. HOWEVER... direct lightning hits are rare. More common is a nearby hit that induces currents and voltages everywhere. *That* can often be handled. Things like surge protectors will at least improve the odds. While those things are often grossly overpriced, it is true that protection is usually in some sort of proportion to cost. Even a few MOVs and a fuse or two are better than nothing. Protection for phone lines is trickier, and is best bought commercially, but it too does help. Industrial-strength modems often include their own protection, but hobbyist-grade junk is prone to eliminating anything that costs an extra fifty cents. -- Anyone who buys Wisconsin cheese is | Henry Spencer @ U of Toronto Zoology a traitor to mankind. --Pournelle | {ihnp4,decvax,uunet!mnetor}!utzoo!henry