Lightning & Bathtubs

[letterman]

We are always told to never take a bath when it's lightning because of the possibility of electrocution if the lightning travels through the metal plumbing. This makes sense. But what if the plumbing connected ot the tub is all plastic? These days we have PEX, CPVC, and other plastic pipes supplying the water to the tub, and PVC drain pipes. Since the tub is not connected to any metal plumbing, is there any danger?

I'm not planning to take a bath or shower during a storm, but I just heard this warning on tv again, and it got me wondering if there's any danger with all plastic pipes. It kind of seems like this may be an outdated warning, if one knows for sure there are no metal pipes connected.

[Joseph Meehan]

I have also heard that, but I have never been convinced. Since I will admit I am not sure, there are a number of possibilities some fatal and some not noticeable, I think I will just avoid taking shows during thunder storms. Of course I would much rather watch and enjoy the storm than to bath during it. I really like them. I grew up where the best part of summer was watching out the kitchen window waiting for the lighting to hit the big power line going into the electrical substation where it would produce one lovely set of fireworks. I find a thunderstorm soothing.

[Jim Yanik]

[e-mail] wrote in news: [e-mail]:

the WATER itself is conductive.

[Oren]

I abide by what I was taught. Don't shower, wash dishes, talk on the phone and be sure to "unplug" the television during a lightening storm.

[David Nebenzahl]

On 5/30/2008 4:44 PM Oren spake thus:

Thunderstorms? What are those?

Oh, yeah, now I remember; used to live in Chicago and Tucson, both of which have spectacular lightning storms. But out here in the San Francisco Beige Area? Nada, zip, nil. Maybe one good thunderclap in two years.

[nick hull]

Not very, and the pipes themselves are seldom in a position to be struck. The problem comes from induction, which is only a problem in metal pipes.

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

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[Red Green]

David Nebenzahl wrote in news:4840d7d3$0$4986 $ [e-mail]:

Never knew that. I would seriously miss T&L storms. Fascinating to me. Some of the still photo shots I've seen caught on high speed film are amazing.

I look at a bolt of lightning and see the future of energy when they learn to harness it. Let Exxon & OPEC rot in hell. I know I'll never see the day. Whether mankind does is questionable.

[gfretwell]

Mythbusters played with these things in the power company lab. and figured out all sorts of bad things could happen in a lightnng storm (shower, phone etc) The main lesson was they had to lift the ground electrode cable to get any of these bad things to happen. A properly bonded and grounded house should be safe. If everything is bonded you are a bird on a wire or a helicopter lineman. The same basic principle is true in your surge protection but I am not getting in that flame war.

[David Nebenzahl]

On 5/31/2008 6:20 PM Red Green spake thus:

I miss 'em too; the drama, the raw power, the tree outside the house split in half the night before. That's the stuff! I'm still a Midwest boy at heart.

We have wimpy weather here by comparison. Few hailstorms, no tornadoes, etc. Just a lot of fog ...

Yup.

[Red Green]

David Nebenzahl wrote in news:48424cac$0$4947$ [e-mail]:

When it vaporizes shit, that's really cool :-)

[dnoyeB]

That is totally untrue. Lightning is static electricity, its going to behave differently than your standard A/C 3-phase loop. This is like saying because you have a lightning rod, you won't get struck by lightning. The only thing a lightning rod means is you are less likely to get struck, but if you do, it will be right in the rod.

So a "properly bonded and grounded" house will be less likely to get struck, but if it is, it will be right in the "bond and ground."

There is no way around this. The only thing you have going for you is Gauss' law. And that may not save your ass.

[thuib]

[bud--]

I read gfretwell as saying that with proper bonding there won't be damaging voltage between parts of the electrical system. Like a "bird on a wire", or perhaps 2 birds on the same wire that touch each other. With proper grounding (earthing), the voltage of the system to 'earth' is minimized. [But for protection from a direct strike to a house you need lightning rods.]

Myhtbusters disconnected grounding (earthing) so there was dangerous voltage between the system and 'earth'. [The mythbusters earthing was probably much more effective than a house.]

Far as I have read, lightning rods do not reduce the probability of a building being struck by lightning (although some manufacturers make that claim).

[ransley]

I know someone who was killed by talking on the telephone- landline from Lightning . Ive been struck twice at my home, Lightning is not something to enjoy. Do what you can, but dont risk it. Lighning moves as 500000 v plasma by air killing anything

[dnoyeB]

The bird on the wire analogy is bad. The bird is not "grounded" and neither is the wire. So what in this analogy is grounded?

A lightning strike results when static builds up. Grounding the house, and creating sharp pointy objects into the air is a way for the static charge to leak off and disipate. However, if the build up is really quick, then the lightning strike will be right in the same place that was leaking off the static. The lightning rod.

A lightning rod is like a hole in a dam. They allow the charge to leak through reducing the static electricity pressure. However, just as in a dam, if the hole is not enough, then the burst will occur right at the hole.

[bud--]

Protection might include a service panel surge suppressor and connecting the phone and cable entry protectors to the 'ground' at the power service. If you had a surge current to earth of 1000A and a very good resistance to earth of 10 ohms, the power system ground will rise

10,000V above 'absolute' earth potential. Since the voltage on power and phone wires is clamped to the power system 'ground', and the cable ground is the same, all wires will rise to about 10,000V above absolute ground. The voltage between the wires is safe for the connected equipment. All the wiring is the 'wire'. The 'bird' is all the equipment connected to the wiring. It also floats up to 10,000V but doesn't know it. Similarly, gfretwell said "you" are the 'bird'.

A couple manufacturers claim their version of a lightning rod reduces strikes by 'leaking' charge. Tests at NASA and elsewhere showed they didn't reduce strikes. Everything I have read is that lightning rods are just a relatively safe place for lightning to strike.

[gfretwell]

I am a fan of lightning rods. I took a direct hit on the lightning rod above my weather station last summer and all I lost was the serial port on the PC connected to it. The PC still works. I am in SW Florida where ass kicking lightning is a daily thing for half the year. I did lightning mitigation for a big corporation that sells Business Machines Internationally. We had over a thousand customers who couldn't turn off their machines and unplug them every afternoon. We got pretty good at eliminating "surge" damage. The biggest single thing I can say is you need good bonding practices. Most people don't do that.

I would want to go look at the bonding and surge protection on any phone that killed someone in a lightning storm. I bet you would have cause for a wrongfull death suit against the phone company. If this is something that you could normally expect to happen we would have people dropping like flies around here all summer.

[dnoyeB]

Cable company did not ground my cable line. I did not know till o ne day during a storm I saw sparks jump from behind the TV, and the cable model and router attached to it went dead. Next day I went outside to look and noticed there was no grounding. I chewed them out and told them to replace my stuff. They rushed out and grounded it but send me to some other department which I assume was the professional deny replacement department. I let it go...

[w_tom]

That pointy little rod will discharge miles of air between cloud and ground? When ESE providers submitted their products approved by the NFPA. NFPA had one simple problem. No proof and no research exists that ESE devices (that discharge air) work as posted here.

If discharging air causes no lightnng, then the Empire State Building (a conductive steel and concrete rod) is never struck? Nonsense. Even a wooden structure is sufficiently conductive enough to discharge that air. Why does lightning strike a wooden church steeple? Because discharging inches of air does not stop lightning.

Lightning will strike. Does lightning strike a conductive material (ie wood) destructively or does it strike a well earthed lightning rod? How good is that lightning rod? Lightning energy gets dissipated destructively in a building (ie wood) or gets dissipated harmlessly in earth. Stopping lightning was the ESE manufacturer claim made to NFPA. That claim was completely rejected.

[dnoyeB]

Yes. The same force that causes the lightning between "cloud and ground" also causes the static to leak off. Its the nature of static electricity.

Never said it causes no lightning. If you read somewhere that lightning rods prevent lightning then it was not from me.

Its not condictivity that leaks off static charge. Its the pointyness. You will have to undestand Gauss Law. A conductive structure that does not have pointy tip will not leak off charge nearly as much as one that does. That is why when you see devices that are trying to "create" lightning by storing up charge, they will be as "unpointy" as possible. And whats the most unpointy thing you can create? A shpere.

Stopping is an impossible claim. Unless it chases away the clouds...