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Re: Whole House Surge Protector

NASA studies have concluded that near strikes have caused data changes in on-board computers on rockets. That would suggest that there is some inductive coupling going on there.

They never said anything about inductive coupling. That is your speculation.

Demonstrate same with a PC motherboard mounted with multiple ground standoffs. Place that computer on a glass tabletop (because wood and other materials are too conductive). Build up static changes using leather slippers and a nylon rug. Static shock the chassis's near end so that current is outgoing via its power cord at the far end. Computer will crash - without damage.

Why? That motherboard has a large copper ground plane completely across the board. Static current entered motherboard on nearby standoffs, conducted across the ground plane, then exited via far end and power cord.

Transient current across a motherboard's ground plane creates a well understood voltage difference. Ground plane has significant impedance. That static current created potential differences between ICs.

How to eliminate data changes. Replace all but one conductive standoff with nylon stand offs. Create a single point ground. No more static electric current across the motherboard. No current on the ground plane means no ground plane noise and no data changes. Data changes exist only when current has both an incoming and outgoing path through that motherboard.

This same solution is implemented on flight hardware. But sometimes not fully implemented due to other design constraints. Therefore something that should never happen - a direct lightning strike - causes no hardware damage but can cause data changes. Lightnings currents sufficient to create ground plane noise ... just like that motherboard and static electric demonstration. Ground noise that causes data change - and no hardware damage.

Airplanes must be more robust. Direct lightning strikes to airplanes is routine and without even data change. If your speculation was real, data changes and hardware destruction would be routine in airplanes. Reality - those induced surges do not exist.

X happened. Without technical facts; only speculation. Therefore it proves Y must have created it? Nonsense. Junk science reasoning.

That induced current is typically ground noise or something equivalent. Therefore only data change. Damage means current incoming and outgoing destructively. Earthing always required so that no destructive currents are inside the building. Thousands of amps - direct lightning strike - only four feet from a PC and it did not even blink. Your example is current actually inside the black box.

No earth ground mean no effective protection. And again, a solution - even this one - involves single point grounding.

Re: Whole House Surge Protector

Westom , have you ever seen an electrical substation being built ? The entire foundation of the site is criss crossed with 4/0 copper wire and depending on the size , hundreds of copper ground rods . EVERY peice of equipment and every structure , even the fence posts are tied to this ground grid . Do you define this as " single point earthing " ?

Re: Whole House Surge Protector
djohns wrote:

EVERY peice of equipment and every structure , even the fence posts are tied to this ground grid . Do you define this as " single point earthing " ?

Exactly. Every structure must have single point ground so that every incoming wire is connected. Whereas homes may only have a few ground rods. Or homes constructed by an informed builder have Ufer grounds. In every case, single point ground is doing two functions: equipotential and conductivity.

This builder created single point ground on a rocky mountain. Red how effective:

Why do so much more? Massive additional earthing only provides minimally increasing improvement. Appreciate how much more money is spend for a minor improvement ... because earthing is that critical. Earthing that makes surge protectors in each substation effective.

Another professional demonstrates same. Every wire between two structures must be earthed at both ends - where that wire enters the structure. In this case, a building and an antenna tower. Each structure has its own single point ground. Any wire that enters either structure must first be earthed:

To make both single point grounds better, a buried wire interconnects both grounds.

Wires from a well earthed substation and a well earthed telephone CO still must be earthed at the local building before entering that building. Even underground phone lines (in that figure) are earthed before entering.

Even if wires enter a substation underground, the substation still gets superior earthing. Appreciate how much additional work is performed just to get a little better earth ground. Earthing was always that critically important when surges must never do damage.

Cougars1996 original post suggests surge damage to underground wires. Apparently those wires were not properly earthed at both ends either directly or via a 'whole house' protector.

Re: Whole House Surge Protector
deadshort wrote:

We all gonna be earthed at some point. LOL

True, we just do not know when.;)

Re: Whole House Surge Protector

We bought our 1967 ranch in late 1999, and spent the next ten months rehabbing before moving in because the well-built house had been horribly let go. In addition to gutting the kitchen and both baths, we replaced the septic system, heating system, roof, and the electrical from the outside line in. Only the bedrooms and living room kept their original wiring, and that only to the nearest junction boxes. All switches and light fixtures were replaced. Our electrician was excellent. He installed the new boxes (we added a separate one in the garage), and hooked everything up. My husband ran all the wiring, and he was meticulous.

So, when appliances started screwing up over the couple of years, we blamed the appliances. Well, the lightning strike that hit our properly-grounded dog fence took out the television. But, mostly, we cursed the appliances until one day I was watching the furnace being repaired (under warranty) for the third time in a year when the guy commented, "Your area must have had some surge last night; This is my third stop in a quarter mile." Right then, the bells in my head went off so loud people in the next county must have thought it was Sunday.

I started researching whole-house surge suppressors that day, and had best choice and cost of installation all figured out when I followed a thread about a power company in another state that offered it as an add-on service. I looked up our power company, and sure enough, they'd just started the same thing. For $67 up front, and $5/mo thereafter, they installed a whole-house surge suppressor and provided us with five point-of-use suppressors and a full-replacement warranty on all appliances, systems, and electronics should a surge get through. Also, they'll replace the suppressor itself if it gets fried.

We've not had a single electronic failure In the six years since we had it put in, which is pretty remarkable considering the whole town sits on top of granite, so we get pounded by lightning any time there's a storm. We've had hits on trees within fifty feet of the house several times. Our cost to date is approximately $375, which is, if you include the cost of the five high-quality POU's, about what I'd have spent to buy a similar unit and have it installed. From here on, I'd say the $5/mo is well worth the peace of mind. Not having to listen to hubby rant about repairing flaky appliances; now, that is priceless. :D


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