TK0GRM1%NIU.BITNET@uicvm.uic.edu (Gordon Meyer) (07/12/89)
Last September I lost a modem in a lightning storm. My computer and the modem itself (external) were turned off, but still connected to the phone line and the electrical outlet. I was home at the time and after a very close (or at least LOUD) bolt all of the lights on my modem came on, my telephone answering machine went off (started playing the announcement message) and all of the LEDS on my GTE memory phone lit up. I knew immediately that this was going to be expensive. <grin> The answering machine survived the ordeal without damage. The telephone survived okay but I had to remove all of the batteries to get the lights to go back off. The modem was killed as were two chips in my computers RS232c card. I lost telephone service (no dial tone) for about 15 minutes, it came back all by itself (how I know this in a second...) Now I'm almost a complete novice when it comes to the telephone network but I assumed that somewhere along the line there should have been arrestor to stop this spike before it reached my line. (I wonder if I would have been shocked had I been on the phone at the time?!?) I went to the telco to complain...(Contel) (yes, I went in person) and spoke with a lower level managment person. I had a hell of time convincing him that the spike had come over the phone line...and not the power line (he wanted me to take my complaint to Commonwealth Edison). Finally he checked the tarrifs and decieded that if a fault could be found in the spike arrestors at my sight then the Telco would discuss paying the damages. He really doubted that the spike even came over the phone line because the protection "fuses" would have blown and stayed blown...requiring physical replacement. Since my service was working, and there hadn't been any repairs (thus it fixed itself) the fuses hadn't blown. I have no proof that the spike did come from the phone line...other than the fact that only phone equipment went bonkers. And the phone was dead for a short time. Anyway..to bring this long story to an end he sent out a repairman who checked my line to see if it met "specs" (it did) and I ended up buying a new modem myself. I don't harbor any ill feelings or regrets but wonder what those of you who are more familar with the system would have to say. -=->G<-=- PS: Yes, I now have a phone line surge protector, an rs232 surge protector, and loss/damage insurance on my PC. :)
ron@ron.rutgers.edu (Ron Natalie) (07/12/89)
Anything billed as a "lightening arrestor" as are the things at the entrance to your house for the phone lines, are there to avoid fires from lighting strikes. They don't operate anywhere near quickly enough to stop electronic equipment from being damaged. Likewise most of the "surge suppressors" on the market are just MOV's, and while these have use on AC power lines, if that's all they used in your telephone surge supressors (likely) it's not adequate either. -Ron
julian%bongo.uucp@eecs.nwu.edu (julian macassey) (07/13/89)
In article <telecom-v09i0231m03@vector.dallas.tx.us>, TK0GRM1%NIU.BITNET@uicvm. uic.edu (Gordon Meyer) writes: > Last September I lost a modem in a lightning storm. My computer > and the modem itself (external) were turned off, but still > connected to the phone line and the electrical outlet. (stuff deleted) > all of the LEDS on my GTE memory phone lit up. I knew immediately > that this was going to be expensive. <grin> The answering machine > survived the ordeal without damage. The telephone survived okay > but I had to remove all of the batteries to get the lights to > go back off. The modem was killed as were two chips in my > computers RS232c card. I lost telephone service (no dial tone) > for about 15 minutes, it came back all by itself (how I know this > in a second...) > Now I'm almost a complete novice when it comes to the telephone > network but I assumed that somewhere along the line there should > have been arrestor to stop this spike before it reached my line. > (I wonder if I would have been shocked had I been on the phone > at the time?!?) I went to the telco to complain...(Contel) (yes, > I went in person) and spoke with a lower level managment person. > I had a hell of time convincing him that the spike had come over > the phone line...and not the power line (he wanted me to take This is not unusual, telco biz office people can sometimes be staggeringly ignorant about technical stuff > my complaint to Commonwealth Edison). Finally he checked the > tarrifs and decieded that if a fault could be found in the > spike arrestors at my sight then the Telco would discuss paying > the damages. He really doubted that the spike even came over > the phone line because the protection "fuses" would have blown > and stayed blown...requiring physical replacement. Since my > service was working, and there hadn't been any repairs (thus it > fixed itself) the fuses hadn't blown. I have no proof that > the spike did come from the phone line...other than the fact that > only phone equipment went bonkers. And the phone was dead for > a short time. Anyway..to bring this long story to an end he sent Getting lightening strikes on phone lines is not uncommon. Yes, in the U.S. telephone lines have either gas or carbon surge arrestors that will conduct a surge of over 300V or so to ground. If the surge is big enough, the carbon arrestors (which are slower than gas, but cheaper) will permantly short to ground and remove you from service until the telco comes out to change them. In Bell Pub 48005 a standard single line phone should be able to survive a simulated lightning strike of 1,000Volts @ 1,000Amps. And Yes a standard AT&T, ITT or Comdial 500 and 2500 set will, as will an ATC Mickey Mouse phone. Cheap and sleezy phones may or may not survive a hit. Many answering machines will die. A few years ago a rep for an answering machine Co in the Kansas area told me that it was not uncommon for over 300 machines to be brought in for repair after a good day of thunderstorms. So anyhow, the protector that the telco puts in will help some if you have a hit, but the equipment has to do some of the work too. If you look at some equipment, you will notice surge protection devices of various kinds. There are series carbon composition resistors, varactors and back to back zeners, besides gas discharge devices. So I regret to say that you are somewhat responsable for the equipment on your lines in these days of deregulation. But in the old days, the telco wouldn't have let you put all those modems, fancy telephones or answering machines on "their network". I have seen phones and modems that are just charred circuit board, some with big holes in them after a lightning strike, so yes, you can be killed if this happens. In the 24 June issue of New Scientist (p. 55) there is a mention of someone being zapped in the ear by a phone reciever during a thunderstorm. Yours with gas discharge tubes in his arrestors. -- Julian Macassey, n6are julian@bongo ucla-an!denwa!bongo!julian n6are@k6iyk (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495