Dan_Jacobson@ATT.COM (05/24/91)
Outside there is a big lightning storm. Should I risk the brief moments of a closed liquid circuit between me and the plumbing system by using the restroom? [I need to know soon.]
jjhoxsey@vela.acs.oakland.edu (Kuros) (05/24/91)
In article <1991May23.223109.19908@cbfsb.att.com> Dan_Jacobson@ihlpz.ATT.COM writes: >Outside there is a big lightning storm. Should I risk the brief >moments of a closed liquid circuit between me and the plumbing system >by using the restroom? [I need to know soon.] I dunno -- can't you just "hold it"? I do recall reading in Cecil Adams "The Straight Dope." that there was once a dead man found in the subway tunnels who had died from electrocution. The evidence was clear-but I'm sure you don't want to hear about it-that the man was urinating on the third rail of the subway system. For you rural propellor-heads out there, the third rail is the electrical supply for the subwar car(s) that is very much like a normal train track rail. Now whether or not your plumbing is safe.... Besides, isn't it known that you shouldn't be on the computer during an electrical storm? %) -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- "Even I must take a break from | jjhoxsey@vela.acs.oakland.edu (Kuros) wackiness occasionally." | Gogo Dodo | The IRC Silly Knight (w/rubber chicken) -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
rbrink@hubcap.clemson.edu (Rick Brink) (05/24/91)
From article <6556@vela.acs.oakland.edu>, by jjhoxsey@vela.acs.oakland.edu (Kuros): > >>Outside there is a big lightning storm. Should I risk the brief >>moments of a closed liquid circuit between me and the plumbing system >>by using the restroom? [I need to know soon.] > > I do recall reading in Cecil Adams "The Straight Dope." that there was > once a dead man found in the subway tunnels who had died from > electrocution. The evidence was clear-but I'm sure you don't want to > hear about it-that the man was urinating on the third rail of the > subway system. For you rural propellor-heads out there, the third > rail is the electrical supply for the subwar car(s) that is very much > like a normal train track rail. > Some time you urban nerdians are in the rural country side, try urinating on an electrified cattle fence. You'll live through the experience, but you'll gain some respect for propellor-heads who know enough not to do it...
mkaminsk@cvbnet.prime.com (mailhost) (05/24/91)
From article <1991May23.223109.19908@cbfsb.att.com>, by Dan_Jacobson@ATT.COM: > Outside there is a big lightning storm. Should I risk the brief > moments of a closed liquid circuit between me and the plumbing system > by using the restroom? [I need to know soon.] Talk about a painful shock :-) I think you're risking more by posting this message over the phone line. To say nothing about possible damage to your hard disks. So, turn off your computer and go. Mark B. Kaminsky mkaminsk@cvbnet.prime.com Computervision/Prime Computer, Bedford, Massachusetts, USA
imp@solbourne.com (Warner Losh) (05/25/91)
Correct me if I'm wrong here, but isn't the metal plumbing in your house grounded? Is that why the house's electrical system is sometimes grounded to the plumbing? And since it is grounded, wouldn't it have a zero or near zero potential? So there is no problem. However, other examples that have been given assume the "object" is much different than ground potential. Warner -- Warner Losh imp@Solbourne.COM The question to everyone's answer is usually asked from within
jtchew@csa2.lbl.gov (JOSEPH T CHEW) (05/25/91)
>Correct me if I'm wrong here, but isn't the metal plumbing in your >house grounded? In theory, yes. The cold-water system is often regarded as one of the best grounds in the house. However, gotta watch the broad statements. The drain/waste/vent plumbing, which includes the waste stack below the toilet and the vent pipe above it, is trending towards ABS, a rugged plastic, in many areas. Also, metal D/W/V pipes are often joined by rubber connectors. The cold water supply might also include plastic (PVC) links, so the only grounding there, at some points, would be by virtue of the water's conductivity. Various systems are often mixed by do-it-yourselfers or even contractors without caring about electrical matters. Significantly, my cold and hot water pipes and gas pipe were bonded together (at the water heater) at the behest of the electrical inspector (who regarded the D/W/V pipes as a don't-care), not of the plumbing inspector. So here's a scenario: the best lightning target on a roof might well be a piece of metal D/W/V pipe going down to a toilet, but thereafter grounded only by a spark + water path through the toilet and into the cold-water system. And/or other good grounds nearby. A weenie roast, so to speak, seems improbable but plausible. Remember that at a few tens of kiloamperes, fractional-ohm differences get really significant. --Joe "Just another personal opinion from the People's Republic of Berkeley"
tonya@hpldsla.sid.hp.com (Tony Arnerich) (05/25/91)
This reminds me of a very funny story that my brother told me when he was in basic training in the Air Force ('70). It seems there was this rural- raised boy who wondered what would happen when he peed on an electric fence... At least this kid was smart enough to avoid getting drafted. But, seriously, I hope everything came out OK. From the land of no thunderstorms, tonya@sid.hp.com
jfa0522@hertz.njit.edu (john f andrews ece) (05/26/91)
In article <13568@dog.ee.lbl.gov> jtchew@csa2.lbl.gov writes: >>Correct me if I'm wrong here, but isn't the metal plumbing in your >>house grounded? > >In theory, yes. The cold-water system is often regarded as one of >the best grounds in the house. > >However, gotta watch the broad statements. The drain/waste/vent >plumbing, which includes the waste stack below the toilet and the vent >pipe above it, is trending towards ABS, a rugged plastic, in many areas. >Also, metal D/W/V pipes are often joined by rubber connectors. > >The cold water supply might also include plastic (PVC) links, so the >only grounding there, at some points, would be by virtue of the water's >conductivity. > >Various systems are often mixed by do-it-yourselfers or even contractors >without caring about electrical matters. Significantly, my cold and >hot water pipes and gas pipe were bonded together (at the water heater) >at the behest of the electrical inspector (who regarded the D/W/V pipes >as a don't-care), not of the plumbing inspector. > >So here's a scenario: the best lightning target on a roof might well >be a piece of metal D/W/V pipe going down to a toilet, but thereafter >grounded only by a spark + water path through the toilet and into the >cold-water system. And/or other good grounds nearby. A weenie roast, >so to speak, seems improbable but plausible. > >Remember that at a few tens of kiloamperes, fractional-ohm differences >get really significant. > >--Joe >"Just another personal opinion from the People's Republic of Berkeley" I suspect it is more likely that only the drainage conduits may be PVC, as it is still (last I heard) not considered safe enough for the drinking supply. That would mean that as you stand, barefoot, on the ceramic tile floor, making glorious contact with the water basin, you may be at risk. Of course, what are you doing barefoot on a grounded floor anyway??? (Can anyone quantitatively compare impedance of rest-of-water-in-pipes to appendage impedance? That's the ticket ;-)
henry@zoo.toronto.edu (Henry Spencer) (05/26/91)
In article <1991May24.210108.9982@solbourne.com> imp@solbourne.com (Warner Losh) writes: >Correct me if I'm wrong here, but isn't the metal plumbing in your >house grounded? ... Apart from the problem of non-metallic plumbing, which others have mentioned, it is important to realize that just because one end of a conductor is grounded doesn't mean the other end is at ground. "All points on a wire are at the same potential" is a useful rule of thumb when dealing with small currents and low frequencies. Here we are talking about very large currents with plenty of high-frequency components; the rules change. However, it seems unlikely that there would be problems unless there was a lightning strike on the house or very close to it. If that happens, you probably have other things to worry about. Lightning doesn't have to follow conductors at all; it got to you by punching through hundreds or thousands of meters of a very good insulator. -- "We're thinking about upgrading from | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 to SunOS 3.5." | henry@zoo.toronto.edu utzoo!henry
clewis@ferret.ocunix.on.ca (Chris Lewis) (05/26/91)
In article <13568@dog.ee.lbl.gov> jtchew@csa2.lbl.gov writes: >>Correct me if I'm wrong here, but isn't the metal plumbing in your >>house grounded? >Remember that at a few tens of kiloamperes, fractional-ohm differences >get really significant. Or, put another way, at a few tens of kiloamperes, there ain't no such thing as a good ground. (Well, perhaps a superconductor a few square feet in cross-section... ;-) -- Chris Lewis, Phone: (613) 832-0541, Domain: clewis@ferret.ocunix.on.ca UUCP: ...!cunews!latour!ecicrl!clewis; Ferret Mailing List: ferret-request@eci386; Psroff (not Adobe Transcript) enquiries: psroff-request@eci386 or Canada 416-832-0541. Psroff 3.0 in c.s.u soon!
ken@ribo.harvard.edu (Ken Cleary) (05/28/91)
I enjoyed this thread quite a bit. I probably shouldn't post a "serious" followup, but I don't want this thread to fry (OOPS die :) just yet. The trap in a toilet has water in the part you can see, but I'm sure everyone realizes there is an air space beyond that. That combined with the ceramic insulation of the toilet should protect fairly well. It might be more of a problem if the storm zapped a rat in the sewer and made a teenage mutant ninja rat, which came up the drain and did something nasty :-)
chidsey@smoke.brl.mil (Irving Chidsey) (05/28/91)
In article <1991May24.210108.9982@solbourne.com> imp@solbourne.com (Warner Losh) writes: > >Correct me if I'm wrong here, but isn't the metal plumbing in your >house grounded? Is that why the house's electrical system is >sometimes grounded to the plumbing? And since it is grounded, >wouldn't it have a zero or near zero potential? So there is no >problem. However, other examples that have been given assume the >"object" is much different than ground potential. > >Warner Losh imp@Solbourne.COM Plumbing is not a reliable ground! PVC tubing does not conduct appreciable ammounts of electricity. Even copper pipe may have insulating sections put in to stop ground currents from causing electrolysis. The problem is not whether you are grounded or not, it is whether you are in a significant ground path that happens to conduct electricity. A college friend was milking the cows during a thunderstorm. Lightning hit about 100 metres away. That cow never ever again let him milk her. He had to call his mother for that one cow. She was sure it was his fault! Irv -- I do not have signature authority. I am not authorized to sign anything. I am not authorized to commit the BRL, the DA, the DOD, or the US Government to anything, not even by implication. They do not tell me what their policy is. They may not have one. Irving L. Chidsey <chidsey@brl.mil>
hollombe@ttidca.TTI.COM (The Polymath) (05/29/91)
In article <2073@ecicrl.ocunix.on.ca> clewis@ferret.ocunix.on.ca (Chris Lewis) writes: }In article <13568@dog.ee.lbl.gov> jtchew@csa2.lbl.gov writes: }>>Correct me if I'm wrong here, but isn't the metal plumbing in your }>>house grounded? } }>Remember that at a few tens of kiloamperes, fractional-ohm differences }>get really significant. } }Or, put another way, at a few tens of kiloamperes, there ain't no such }thing as a good ground. ... The important thing is that electricity doesn't just "follow the path of least resistance." It follows _all_ paths in inverse proportion to their resistance. When you're dealing with multi-megavolts and kiloamperes, it doesn't take a very large proportion to fry you. So pee in a jar while waiting for the storm to pass. (-: -- The Polymath (aka: Jerry Hollombe, M.A., CDP, aka: hollombe@ttidca.tti.com) Head Robot Wrangler at Citicorp Illegitimis non 3100 Ocean Park Blvd. (213) 450-9111, x2483 Carborundum Santa Monica, CA 90405 {rutgers|pyramid|philabs|psivax}!ttidca!hollombe
feldman@urbana.mcd.mot.com (Mike Feldman) (06/07/91)
In article <16288@smoke.brl.mil> chidsey@smoke.brl.mil (Irving Chidsey) writes: >In article <1991May24.210108.9982@solbourne.com> imp@solbourne.com (Warner Losh) writes: >> >>Correct me if I'm wrong here, but isn't the metal plumbing in your >>house grounded? Is that why the house's electrical system is >>sometimes grounded to the plumbing? And since it is grounded, >>wouldn't it have a zero or near zero potential? So there is no >>problem. However, other examples that have been given assume the >>"object" is much different than ground potential. >> >>Warner Losh imp@Solbourne.COM > > Plumbing is not a reliable ground! PVC tubing does not conduct >appreciable ammounts of electricity. Even copper pipe may have insulating >sections put in to stop ground currents from causing electrolysis. > > The problem is not whether you are grounded or not, it is whether >you are in a significant ground path that happens to conduct electricity. A few years ago, our house took a bolt through the sewer vent, which is cast iron and lead and had(!) a ground wire running from the TV antenna to the roof vent. The gook in the upstairs bathroom trap was on the bathroom ceiling, the bathtub drain started leaking, and some of the leaded joints in the cast iron were melted and blown through. There was even a chink of plaster blown off of the pipe chase in the kitchen. It took the ozone smell hours to go away. This happened in the early morning just minutes before my normal visit to the bathroom. Now, every bathroom visit during a storm prompts me to imagine a bolt climbing the conductive fluid stream! -- Mike Feldman, Motorola Computer Group, (217) 384-8538, FAX (217) 384-8550 Urbana Design Center 1101 East University Avenue, Urbana, IL 61801-2009 UUCP: ...!uiucuxc!udc!feldman, Internet: feldman@urbana.mcd.mot.com