How Important Is Grounding Your Home Against Lightning?

[RobertBrown]

Having your electrical system grounded correctly, and protecting yourself and your house against lightning are 2 differtent things. Grounding a lghtning strike is a crap shoot, it can be done, but at great expense and I don't think even the best most expensive lightning protection is ever 100%.
Lighting can and will enter your house through your electrical system, phone and cable wires or your plumbing...or any thing else that could possibly conduct electricity. You can try to protect your electronics with surge protectors but if you get a big enough jolt all bets are off. I avoid metal plumbing pipes or taking a shower during an electrical storm.
You're a lot safer in your house than outside. I get a lot of lightning here in Florida and I've lost some stuff. The way I look at it, when I'm inside, I'm as safe as I'm going to get when it comes to lightning. It's one of those things in life you can't control, when your times up....it's up.
Many commercial buildings have a system in place to mitigate lighting strikes. On the roof of these buildings you will find a series of lightning rods connected with large aluminum cables. These cables run down the outside of building to large ground rods. This system is designed to channel the tremendous voltage around the building to ground.

 

[Lady Tonka]

I just love TBN-ers! I've only been here a short while, admitted right up front that I am a Greenie/Dem/Lib, and STILL you all take the time to share your wisdom and suggestions with me! Such a helpful group on this site, and I much appreciate all the input.

A contractor friend of hubby's rolled his eyes when he heard about this concern of mine and told me to GET A GRIP and obsess about the overdue Magnitude 9 Cascadian Subduction Zone mega-quake due in this area and/or Mt. Rainier blowing its stack if I needed something to worry about. So I took a deep breath and settled right down because I was already comforted by what responses I got on this thread.

Thanks! :thumbsup:

(Hmmm...do you think I should move further inland?) :laughing:

 

[jeff9366]

I recently built a retirement home in north-central Florida, where there is a lot of lightning.
I had a professional lightning protection service install ten (ten) lightning rods on the roof. These are cabled together under the roof and grounded four times with copper ground spikes 48" long. The air conditioner, aluminum alloy fence and Florida Room screens are also in the system and grounded individually. Cost? $2500 as part of new construction. Probably will save at least one computer and one flat screen telly over the next ten years.... Service provided a lifetime guarantee covering all equipment and fixtures damaged by lightning after rod installation. No problems after first two years. It is reassuring to know the Kubota is safe.

The service installs lightning protection on the local nuclear power plant....a good reference.

 

[Branchchipper]

Cool- and your husband's friend is right!
In western OR & WA,as well as far-north CA, you are fairly likely to experience a HUGE earthquake in your lifetime (unless you are 80 or 90).
Plus, there are a number of other natural hazards that are far more likely to cramp your style than a lightning strike.
Being prepared to survive on your own for a while due to any type of event is something worth fretting about (no power, no fuel, no food, etc).
So is securing your home against quake motion (strapping your water heater, etc, etc, etc), as detailed here:
Washington Military Department Emergency Management Division - Preparedness - Personal Preparedness - Prepare your Home
Have fun!
(and forget about moving further inland- the CSZ quake will be a region-wide event; a house in Spokane might be OK, but you'd probably still be without power for a month! Plus, there's WAY more lightning east of the mountains, as your link shows)

 

[Pete Judd]

Tonkagilr, I would not worry about it, I am a ham radio operator and have a metal mast sticking 68ft up into the air on my sail boat. Don't worry about it, I have all kinds of antennas up in the air around here as well. Not to far from you and yes it was a great display here, started at about 10 am, and went till 4 am. Just got to be neat to watch and listen to for all those hours.

 

[dex3361]

That's a really good ground. Code for a service ground is 25 ohms.

Really hard to get 3 ohms, most times you have to work hard for it. That is for areas where surge damage is costly. The last ground survey was because of surge damage and the cost of 1 storm was costly. To achieve that good of ground it required a solid copper plate and a lot of #2 copper(all buried deep).

 

[The kid]

There are two types of grounds when talking about residential homes. Electrical (grid) and Earth. Local and state electrical codes requires you to tie them together. Why? To lower the ground potential or resistance between them. That is why when you look in a modern electrical breaker panel a wire from the electric utility meter base is physically connected to the ground buss in your panel. Outside the meterbase has two grounds. Electrical grid and earthen grounds. By having a good earthen ground lowers the risk of damage to a home from a nearby lightning strike.

Unless you have lightning rods installed across your roof and sufficient grounding then a direct hit from lightning will saturate the home looking for that path to ground. It destroys anything in it's path. In the Nashville area a home's gas meter was hit by lightning and instant flames. The family escaped with the clothes on their backs. Protecting the home against lightning surges is another story.

Many companies will try to sell you a strip to protect your goodies. Think of your house as a big bubble around it. This is considered the "whole house" protection. This is installed at the source such at the meterbase by the electric utility or installed in the breaker panel by a qualified electrician. This type of protection only protect electric motor type devices which already have good ground protection.

Now you want to create a bubble inside the bubble with high quality MOV surge strips to protect your expensive electronics. Mind you I began and said "surge" and not direct hit.

We had a direct hit on our underground to overhead service recently at the transformer and it got some of my electronics that was on a quality surge strip. Someone mentioned lightning arresters at the transformer. That only protects the utilities transformer. That's all. Back to the good ground. If you have a good bonded ground, damage will be minimal. A poor bonded ground and major damage throughout your home.

The key to protecting ones home is good grounding. Tighten connections in the breaker panel every few years. Have an electrician tighten connections inside the meterbase with proper permission from the local utility. Utilities are serious when you cut one of those plastic seals. I hope it kind of explains what you can and can't prevent when it comes to lightning and surges. -Robert