Zap! Crash! … and than all the power goes off in your house. Your inverter has been fried and it’s going to cost you thousands of dollars to replace everything. If only there was some little device that could protect your renewable energy system from things like power surges or lightning strikes.

Luckily, there is… and they’re called lightning arrestors. Lightning arrestors are like the fuze box in your home. If the amount of power coming down the line exceeds a certain threshold it stops the power from flowing thus protecting all of the expensive electronics in your house.

Before we move any further let’s take a look at what actually happens when a lightning strike occurs. For your wind generator the strike will hit the tower and although much more unlikely a strike to your solar panels is actually a strike to your house.

After the lightning has struck there is a huge amount of power… on the order of thousands of volts and tens of thousands of amps. A lightning arrestor works by limiting the voltage difference between any two wires and ground. When lightning strikes there is a huge voltage and amps on one side, but quite a bit lower on the other side that is connected to the inverter so the lightning arrestor basically restricts the flow of electricity so nothing gets damages.

As with any good renewable energy system though, it’s going to be important that you plan for multiple failure points in your system so that overall you’re better protected than just plugging a lightning arrestor in right before you inverter and hoping for the best.

Wind Generator Protection

Your wind generator tower is a perfect target for lightning to strike. A nice tall metal object that is taller than everything else around it. Plan to have at least 4 lightning arrestors if you have a wind generator so you can minimize the impact of a direct hit.

As a side note, make sure that any lightning arrestors that you get are rated for at least 50,000 amps. The first one is going to get installed at the top of the tower so you can dissipate most of the energy before it’s even reached the bottom of the tower. If you haven’t yet properly grounded your wind generator tower I strongly recommend you do it ASAP as without proper grounding there’s nowhere but to your house for the energy to go.

The second arrestor gets placed at the bottom of the tower which should get rid of pretty much the rest of the energy from the lightning strike. There is another one placed just before your inverter AND just before your fuse box. The reason is simple… should the lightning still get past the first two you really don’t want it to take out your inverter. Secondly, IF it gets past your inverter you have got to stop it before it gets into your your house and wreaks havoc on all the sensitive electronics in there.

In most cases the first two in the tower will do the job just fine, the ones before the inverter and the fuse box are there simply as an added precaution.

Is it worth it?

It really depends on what you think. Personally, I would rather fry $200 worth of electronics than thousands or tens of thousands of dollars of equipment.

Solar Panels Protection

Since the likelihood of your solar panels suffering a direct hit is much lower than a wind generator tower, you don’t need to go quite so crazy with the setup. An arrestor before the fuse box, before the inverter, and one at the junction box where all the feeds from the solar arrays meet up.

Should a strike occur the arrestor at the junction box will stop most of it and the one by the inverter will stop the rest (if the first one didn’t stop everything). Should it get past the inverter there’s still one before the fuse box to protect the circuits in your home.

So remember, spend a little money now to protect yourself from thousands of dollars of damage a lightning strike can have on an improperly setup system.