ADSL router and lightning

[biometrics]

 

[Colin62]

Having read this thread from start to finish, a couple things seem apparent to me.

Firstly, I'm pretty sure that westom is an academic. His very adversarial debating style, and his constant repetition of the theory while providing absolutely no useful practical advice are mostly what convinced me of that. And while he is right, it hardly matters. None of us are trying to dissipate a direct hit - we just want to reduce (not necessarily even minimise) our risk to acceptable levels, levels where our insurance doesn't start costing us an arm and a leg. Quoting industrial standard solutions to homeowners is really a dumb idea, although he is 100% correct - provide the best earth that you can practically and allow the surge to be dissipated to ground.

Secondly, while Jorgen isn't exactly impartial, but at least he has the balls to tell us that, and to defend his product using sound logic and practical information, and I suspect that his product is a pretty useful start for a homeowner who isn't trying to achieve 100% connectivity during a storm and who doesn't have AT&T's budget to spend on protection.

And thirdly, I have nothing practical to add to the debate, because like westom, my knowledge of this is theoretical, and I know enough to realise that theoretical knowledge without a practical solution is just smoke up your arse. A clued up electrician doesn't need to understand how a specific device works to know that where he has installed it, it was effective - his advice is worth more than a Nobel prize winner who highlights a product's theoretical shortcomings in extreme situations. So if you're going to take advice from this thread, take it from the guy here who has actually built and tested a device.

 

[airborne]

I don't think a proper surge protection system is terribly expensive, all you need is a correctly earthed ground and a decent DB mounted surge arrestor, a few thousand rand for the best house wide surge protection on the planet sounds pretty decent to me vs R1500 for a switch out device that does the job on just one line and can't protect you from a random direct strike.

That being said if the Astraphobe does what it says it can it certainly has a place in the market, housewide surge protection may not always be feasible, maybe the house's earth wiring is such a mess it would be overly costly to rectify properly or you are renting etc.

I think Westom is barking up the wrong tree but he has made some good points, I certainly learnt some valuable stuff.

 

[k_l 0452]

It appears so. I am on my third router (D-Link) with the previous two having been fried in the last five months. The fibre cable stretches 10 meters to my PC. In each instance, the port got fried, but not the cable which I was able to connect to second and third computer and worked.

Incidentally in the the D-Link router, there is an option to connect the phone line first to the power adaptor supplied with the router. The power adapter has in and out jacks so that the phone may not directly connect to the router, but via the jacks in the adaptor. How good a protection is this?

As far a I know, the reason why you should connect the phone line first to the power adaptor supplied is so if the power surge came through the phone line, it would stop at the adaptor and not travel to the router. By stop I mean it would most likely fry the power adaptor but you save your router and everything else connected to it. If it is still under warranty, you should get the unit sent in for checks.

Most times when a router gets fried, the surge can either enter though 1)wall socket, 2)phone line, 3)LAN port.
You should check the port that got fried, what equipment was plugged into it. Chances are the surge is entering from there and damaging the router port ICs, hence frying the port.

 

[westom]

As far a I know, the reason why you should connect the phone line first to the power adaptor supplied is so if the power surge came through the phone line, it would stop at the adaptor and not travel to the router. By stop I mean it would most likely fry the power adaptor but you save your router and everything else connected to it.

So you think 2 cm parts in an adaptor will stop what 3 kilometers of sky could not? Nothing stops or blocks a destructive surge. If a surge is incoming to the adaptor, then at the same time, that surge current is also outgoing and flowing into the attached modem. A surge current exists simultaneously everywhere in a path from cloud to earthborne charges. Nothing stop or blocks a surge.

Meanwhile, that telco line protection is only doing what power strips hope to accomplish. Again, from the AT&T forum:

Then, to add insult to injury, some strip protectors add Telco and/or LAN surge protection within the same device, trying to be an all-in-one sale. Remember bonding? When Telco or LAN protection is added to a strip protector, if the premise ground, which is not designed to handle surges, cannot handle all of the energy, guess where that excess energy seeks out the additional grounds? You got it! The Telco and LAN connections now becomes the path, with disastrous results to those devices. ...

How does that adaptor, et al do protection without a low impedance connection to single point earth ground? It doesn't.

Protection is always about where hundreds of thousands of joules are harmlessly absorbed. No way around over 100 years of proven science. Once a surge current is inside, it will hunt for and find destructive paths to earth. It will increase voltage as necessary to blow through anythnig that tries to stop or block it. If a surge current is incoming to an adaptor, that same current is simultaneously outgoing into attached electronics. Otherwise no electric current exists.

See a previoiusly posted example of proven phone line protectors. In every case, those superior products always have a dedicated connection for the low impedance hardwire to earth. A protector is only as effective as its earth ground. Protection is always about where energy harmlessly dissipates.

The most common path for a damaged modem or router is incoming on AC mains (or from an attached computer). And outgoing to earth via phone lines. Even a phone line passing adjacent to a metal water pipe can be the outgoing connection to earth.

Damage is often on the outgoing path. Wild speculation then assumes that was an incoming path. Damage means both the incoming and outgoing path need be identified and corrected to avert future damage.