Lightning/Power Surge Protection

I don't know that there's anything you can do if you're actually hit by lightning. But, have a good electrician come out and check your house ground. It should be connected to a big piece of pipe that's driven deep into the ground near the edge of the house. The connection to the pipe may have corroded away. The ground will be less effective if the dirt has been allowed to dry out. Also, have him check the connections between your socket grounds and the outside ground.

There are surge suppressors and there are surge suppressors. A lot of them are crap. Make sure you have one that has an actual number on it for the amount of energy it can withstand (so many tens of thousands of joules.)

I assume you're in a housing development, but if you're a little house on the prairie, you might consider a lightning rod.

If you decide to install a Lightning Rod, Do not attach it to your house. You want the electrical charge to be diverted away from your house; not to it as most people have done in the past.

Place the Lightning Rod away from your house and at a higher elevation.

You could get surge protection on your main electrical panel and you could install GFI breakers for extra protection on those affected circuits.

Lightning has a tendency to strike repeatedly at the same location because of the exceeding good ground originally found is seldom removed.

Walnut trees are known to attract lightning. If there is a large walnut tree nearby, cut it down. The root and sap system provides an excellent electrical ground including during winter months when no leaves are present.

As stated before, the surge protection system should be at the main breaker of adequate joule rating to protect the entire circuit. Self destruct sacraficial feature is often desireable in a surge protection system. If capacity is exceeded, the surge protector must be replaced before restoring power.

Most likely, there is a poorly installed or non-existant neutral and ground at the utiltiy (pole) holding the transformer supply into the house(s). Contact the local utility to inspect and properly install the neutral / ground system including the grounding rod (connection) at the metal grounding rod driven into the earth at the utility meter entrance to the house(s). The local utiltiy is certainly responsible for damages resulting from an identified and properly documented "inadequate ground". A local certified electrician can provide adequate documentation. Please do not fraudulently charge the home insurance policy with the deficiency of the local utility company. Utility Stock holders are responsible for utility incompetence. Please do not make our monthly insurance policy increase.

Remember, The incident can reoccur if not fixed in a timely manner.

I've spent a career studying and testing lightning and designing lightning protection systems, primarily for electric utilities.

The description of damage indicates a probable direct stroke to your structure. All the suggestions are good (including the possibility of damage due to proximity strokes).

Cutting down nearby trees is not necessarily the best approach. In fact, they can provide effective shielding for the home or structures. It depends upon the shielding angle they provide. A home surrounded by trees taller than the home will usually be protected from direct strokes. Although trees with deep root systems are pretty well grounded, separate grounding with ground leads attached to driven ground rods can provide more effective grounding through a lower impedance path and, will also protect the tree.

The most effective protection is to shield the structure to be protected inside a farraday cage. If the structure has effectively grounded metallic siding, for example that is relatively simple but the siding must have multiple grounds, unbroken by chimneys, etc. to minimize the ground path. Similarly, lightning rods (also called Franklin rods) can be effective in the same way but one (unless it is very tall) is seldom sufficient. Again, shielding angles are important. A good rule of thumb is a shielding angle of 30 degrees. If the structure falls within a 30 degree angle below an effectively grounded structure it will be protected against most direct strokes. The exception is the possibility of shielding failure in which the lightning bypasses the shielding.

Other factors such as the magnitude, type and polarity of the stroke (high current, short duration, low current, long duration, positive or negative polarity) also come into play. Over 90% are of negative polarity and half are less than 35,000A.

Just out of curiosity, would you say that houses built with metal studs are more or less prone to lightning that houses built with wooden studs, all else being equal?

The mechanical threat to the building in question is another parameter that needs to be considered. Were a tree to split or topple, what is the potential risk, and the potential damage, to the building, and how does it rate against the insurance premiums paid?

A Lombardy Poplar, a secondary vertical of which presented a threat to a building, was pruned recently so that the offending limb could not strike the building. The main vertical was left in place so that, preferentially, a lightning bolt would hit that rather than the building.

Planning permission may be needed to alter limbs of trees. Any live bough greater than 100mm in diameter within a designated Conservation Area in the UK is thereby protected.

Horses for courses...

Lightning rods would be an obvious answer if it struck the house, since properly installed they are 100% effective in protecting the structure, but you don't mention any damage to the house itself, therefore we have to assume it was an electrical surge over the power lines, but I would inspect the roof and exterior structure just in case. Any tall trees nearby should also be checked for evidence of a strike just to rule these things out.

If by chance you have a roof antenna it should be well grounded, and the antenna lead should pass through a well grounded lightning arrestor. Cable and telephone lines also have grounded lightning arrestors installed before entering the structure. Have these lightning arrestors and their grounds checked.

I would start by contacting your electric utility and have them check out their equipment (transformer, grounds etc) and in particular their grounded neutral that is one of your supply wires. Then, as previously suggested hire a competent electrician to check out your breaker panel, house wiring and grounds including the safety ground to a ground rod or water service. Even if they were in order before, there is a good chance they are not now.

Lightning is "funny stuff" and can have bizarre effects. A nearby bolt can have an electric field that can even damage some sensitive equipment not even plugged in, although that is relatively rare.

You may well never have this happen again on the other hand you might, even after following all our advice: Lightning is that way. However, it can be protected against in most cases (and every case if enough effort is expended, but that is not always practical). There is an element of "luck" (for lack of a better word) in lightning strikes, an element of causality/risk (house on the top of a hill kind of thing), and there is also a large body of knowledge to protect against it's damage.

Good Luck

I work at a major power plant. When lightning trips us off line the loss is approximately $3,000,000/day. You can imagine that we are pretty sensative about such things. We have had excellent results using these guys http://lecglobal.com/ to help us understand and reslove lightning issues.

Thanks everybody for superb advises. Certified electrician to check out the house and then of course TXU (local power co.) to remedy 'whatever.' I wouldn't want this happening again. Great site!!!

ChromaDE

if you get allot of cross over as its called, lighting hits on utility lines. even 5 miles from your house the surge can carry into your home system , companies like GE and josyne make small, no maintenance ( unless it blows up ) low cost "carbon pile" surge protectors that you simply attach to your ac box mains, I use their 240V 3 wire,( 2 hot, 1 grd) for my 200Amp 240VAC mains

they "break over" starting around 320V typically…. When they conduct they remove most of the surge energy in the line, some energy ( usually what did not get clamped below 320V ) will get through .........

So you also have to have additional surge protection which removes what got thru at your equipment although this can be lower surge capability….like the typical surge 6 gang box devices that have both transorbs and MOVs +inductors to damp out this stuff...this way you remove the energy with 2 or 3 devices at a reasonable cost

the key is placing effective surge production at different points from where power enter your home. against a direct strike, good insurance might be the only way and being able to prove it.....RS