How to detect lightning ?

[outbackrob]

It may be not your AC wiring....

If you have decent surge protectors and your UPS is protected, it may not be your electrical wiring that is carrying the surge to your equipment. A buddy of mine bought an EXPENSIVE home audio system. He made sure he had everything well grounded and his surge protectors had surge protectors. Months later he attached an Apple TV via network cable to his otherwise wireless network to improve performance. Soon afterward there was a severe storm. Lightning stuck the pole behind his home. It traveled to his Comcast modem/router, through the ONE wired connection to the AppleTV, through the HDMI cable and into his expensive amp/receiver. His Comcast cable splits after it comes into the house. The side that went to the TV had a lightning arrester on it. The side that went to the modem did not.

Everything that was connected via HDMI to the amp was toast. The old VCR connected via composite cables was fine.

[Automated]

How to detect lightning ?

Fix the house grounding system. Everything else is secondary.

[Pete]

Yup; over the years here have redone my surge protection and have added more grounding....

I did sort of over do it with a commercial surge protector ....

I have the lightning sensor on the roof and could have mounted it in the attic.

That said I am using a shielded two wire coaxial cable for the 1-wire lightning sensor that goes to a lightning surge protector before coming into the house.

The sensor is just a piece of copper connected to the 1-wire device in PVC.

A couple of years ago a friend nearby got a lightning strike and it did damage many appliances, TV, computers on and on (well around maybe 10K or more worth of stuff) ....and light bulbs did burst in his home; one over his son's head while he was surfing the internet....

He asked me to look at his electrical and help him with the installation of a surge protector....

He had DIY'd much of his electric....that said I told him afterwards that a surge protector wasn't going to help him much unless he redid much of his electrical DIYing.

The DIYing of the electrical stuff he did probably caused most of the damage to his "appliances".....

He lost computers, TV's, Multimedia recievers, microwave, alarm panel, et al....

Many folks today do not care about this sort of stuff (LV or HV wiring) until they do get a lightning strike...but then its probably too late anyways .....dumb analogy would be like buying car insurance after you get in an accident....

[NeverDie]

If you have decent surge protectors and your UPS is protected, it may not be your electrical wiring that is carrying the surge to your equipment. A buddy of mine bought an EXPENSIVE home audio system. He made sure he had everything well grounded and his surge protectors had surge protectors. Months later he attached an Apple TV via network cable to his otherwise wireless network to improve performance. Soon afterward there was a severe storm. Lightning stuck the pole behind his home. It traveled to his Comcast modem/router, through the ONE wired connection to the AppleTV, through the HDMI cable and into his expensive amp/receiver. His Comcast cable splits after it comes into the house. The side that went to the TV had a lightning arrester on it. The side that went to the modem did not.

Everything that was connected via HDMI to the amp was toast. The old VCR connected via composite cables was fine.

Good to know. Thanks for sharing the story.

[Automated]

How to detect lightning ?

That story is a perfect example of not having a correct ground SYSTEM for the house. You can ground individual things and surge protectors all day long, and it will not help without a proper single point grounding SYSTEM in place with enough ground rods.

[NeverDie]

That story is a perfect example of not having a correct ground SYSTEM for the house. You can ground individual things and surge protectors all day long, and it will not help without a proper single point grounding SYSTEM in place with enough ground rods.

Is there any particular standard whose compliance we should be aiming for? The NEC codes seem rather minimal for a house with a lot of expensive home automation in it. I read how one person did this, and another person did that. It all seems a bit ad hoc for a topic that's surely well studied.

Not a good example of what I mean, but today I noticed a cheap grounding clamp on my house was looking rather corroded, so I replaced it with a better clamp that's good even for direct burial. Was it worthwhile or unnecessary overkill? I have no idea. If nothing else, it was both inexpensive and easy to do, so I just did it rather than think very hard about it.

[Automated]

How to detect lightning ?

Is there any particular standard whose compliance we should be aiming for? The NEC codes seem rather minimal for a house with a lot of expensive home automation in it. I read how one person did this, and another person did that. It all seems a bit ad hoc for a topic that's surely well studied.



Today I noticed a cheap grounding clamp on my house was looking rather corroded, so I replaced it with a better clamp that's good even for direct burial. If nothing else, it was both inexpensive and easy to do.

The standards you will come across, like NEC, are a standard for electrical safety grounding. That is to say, safety with regard to handling of electricity from the grid. It has little/minimal to do with lightning safety. I am not at the computer at the moment to supply exact links quickly, but a good place to start is to Google single point grounding concepts. In particular, I know Polyphaser put out some good white papers some years ago, so you can search for those as well. The Amateur Radio communities also have some good resources.

In general grounding protection efforts can in a way be thought of as a continuum, with basic electrical (NEC) grounding standards at one end and what a radio station with a several hundred foot antenna would implement at the other end of the spectrum. You should be aiming somewhere in the middle as you will obviously not need to go to the extreme.

In general all wiring coming into or going out of your house should connect to the same common ground system at the point of entry. Then, all grounds should be also commonly connected wherever you have a clustering of equipment, BEFORE they all connect to the equipment, and also linked back to the common ground. There should be more than one ground rod outside, all connected together to the common entry ground point, and spaced at double their length. How many depends on your soil conductivity, but personally I would have no less than 3, and I would bond them with exothermic welds with a minimum of 4 gauge wire. Personally, I am building a ring all the way around the house, and most of them are linked with 2 inch wide copper strap, but I also have a few antennas up so...

You need to minimize electrical potentials across all wiring, and this is what single point ground and ground system concepts are all about. If you do these things then when there is a surge, your protectors have somewhere to send the energy...if it even gets that far. If there is a better ground potential for an energy surge to take THROUGH your equipment, then that is the route it will take. You need to think like the lightning if you will, and design the system with these things in mind. Surges will come, and you want them to flash over your site to ground at the same electrical potentials. When differences arise you get fried gear.

All this said, if you take a direct lightning hit, all bets are off, but at least your house probably won't burn down.

[vasrc]

Resurrecting this subject:

I know it was mentioned, but HA homes usually have LOTS of Cat5/6 cable running around the place and it makes a great antenna for induced currents. We lost two SG200-26P Cisco switches last night after a nearby strike. The power is all UPS and surge protected appropriately (no other damage except a Barix Exstreamer), but this obviously came right into the network cabling, which does have Surge protection on it (commercial grade, with it's own ground rod), but since the two switches are connected via a 150' Cat6 run between the two buildings (underground, shielded, but still a perfect opportunity for a ground potential difference since it's not feasible to bond the two buildings.), it went belly up.. (I'm thinking of putting fiber in to stop that).

So that said, the question is (finally), what's everyone using to protect all of their network/HA (and phone to some extent, although it's usually done at the POP on the side of your house) cabling since even if the equipment is perfectly protected on the power side, letting anything come back into the equipment (which is where it's most likely going to go to find ground) is usually going to blow out that (Serial/Enet/etc) port and most likely the equipment.

And to keep it on subject, I use our driveway alarm as the lightning detector.. Great EMF detector

Z

[Pete]

Relating to detecting lighting I built a little HB lightning sensor which has been up and running now for a few years and working well. It's a 1-wire device using a coaxial cable with a lightning arrestor on it.

Relating to surge protection years ago installed a TVSS from Eaton called a PTX-160. The installation is documented here:

http://cocoontech.com/forums/topic/1...rge-protector/

To date I have only lost my two Rain8net devices due to lightning in the last 10 years. Guessing that it was due to lightning as the lightning strike damaged the neighbors appliances, television, alarm system et al.

I have over the years redone my grounding for the house some.

A flickering of power two weeks ago messed with my outdoor AC capacitor (making it bubble) and shutting down my AC outdoor compressor. I just ordered a surge protector just for the AC outdoor. Writing about it here:

http://cocoontech.com/forums/topic/1...ctor/?p=217137

In the older house I was using photorelays in the driveway (1980's install) and they did function well as lightning detectors.

I do have much catxx cabling as I use it for everything. (that said my network today is at 1/2 of a class c ~ 128 devices)

[Automated]

Here I use a Boltek lightning detector.

[NeverDie]

... after a nearby strike.

Just how nearby was it? Are you saying that the network cable from the ISP was surge protected at the point of ingress, but not the 150 cable connecting the two structures?


By the way, is anyone here monitoring their inbound power and other wiring (data lines, etc) to see what sort of surges are incoming, as well as what's getting through, and thereby have some gauge as to how well your surge suppression is actually working? I imagine it would be fairly cheap and easy to monitor the electric power using a voltage sensor and a datalogger set to look for voltage spikes, and only slightly less easy to monitor for transient AC voltage dips. In this way, it would be interesting to see how much local storm activity can be seen on the wires.

I'm not sure, though, how I'd monitor for unexpected voltages on the coax cable that brings me the internet. I wouldn't want to create any extra signal losses between the ISP and my cable modem.

[Pete]

A while back Michael McSharry wrote an xAP plugin that connected to an old Radio Shack multimeter via an RS-232 interface. I used to use it for a bit. It worked well and just shows your current home voltage. I would see it moving up or down all of the time. (not much though).

It is here:

http://board.homeseer.com/showthread.php?t=140505

The Eaton PTX160 TVSS that I am using has a surge switch to the fuse panel that will alert me of a surge.

The UPS that I utilize also indicates voltage status.

The only lightning issue here that cropped up was a few years back. It took out my two Rain8nets but nothing else. Neighbors lost many appliances (including TVs) and alarm panel and other stuff.

[Rupp]

I used my Boltek for years before a lightning strike took it out It was too expensive to replace so now I use this web site which works great.
http://www.lightningmaps.org/realtime?lang=en

[vasrc]

Just how nearby was it? Are you saying that the network cable from the ISP was surge protected at the point of ingress, but not the 150 cable connecting the two structures?

Surge protected, but on further review we found a couple of trees nearby (we live on 6 acres with 50% of it forested) split down the middle and down by the river, a microburst/tornado, made a swath about 10' wide.. Probably nothing we could have done with such a close strike, but I'm still going to replace the run with fiber just for the experience. (Last time I played with Fiber was with the Union Pacific in Denver in the 80's.. Lot's easier now I hear ..

Z

[Automated]

I used my Boltek for years before a lightning strike took it out It was too expensive to replace so now I use this web site which works great.

http://www.lightningmaps.org/realtime?lang=en

Interesting. Do you have a script, or a plugin, or?