How many Joules?

You also need a GOOD earth ground. That old ground rod and loose wires won�t provide a good path for the energy to travel in. Lighting energy is usually high frequency energy, so it behaves more like Radio Frequency energy from a transmitter than regular AC or DC power. This means that in the earth bounding system there should be no sharp bends to the wires, large conductors, clean and tight connections, etc.

You really need at least two different suppressors on a home. The first one is rated for location C or whole house. This is normally at the main service entrance. These devices are designed to handle large currents and typically have a clamping voltage in the 500V � 800V range and are typically in the $40 - $80 range.

The second suppressor that is needed is for location A or point of use. The most common is the plug in surge suppressor. These are designed to see a much smaller amount of energy than the location B suppressors.

The most important rating on a plug in surge suppressor is the clamping voltage. The IEEE-1449 Transient Voltage Surge Suppressor test that surge suppressors are rated with list the best clamp voltage possible at 330V line to line and 330V line to ground. There are many suppressors that have a 330V � 330V rating in the $5 - $50 range. These devices are usually designed to suppress many small spikes, or one or two larger ones before that need to be replaced.

I recommend that most people purchase several of the plug in suppressors. Due to the frequency of the surge energy it may not prorogate down the different runs of wire in the home the same. Some outlets could see almost no surge energy, and others could see the bulk of the surge energy that entered the system.

The purpose of the suppressor is to provide a path around the device that is being protected. They can shunt the energy to or from the earth ground, across the line and can convert it to heat. The goal is to dissipate the energy before it can damage or destroy the devices you are trying to protect. The more suppressors you have the better the suppression should be.

This link has a lot more information:
Link

For something a bit more technical:
Link

In this era of electronic devices, everyone should have a surge protector in the service entrance panel. There are protectors that plug-in like a breaker or there are wired-in versions. Square-D, Joslyn, PolyPhaser, and others make the wired in versions. It pays to have both wired-in whole-house protection and plug-in protectors.

Lightning protection can become quite complicated. PolyPhaser has lots of info on their website about lightning protection and grounding.

While protecting the power lines, don't forget to add protectors to the telephones and the cable TV/satellite/antenna lead.

• Joslyn

• PolyPhaser

• Joule

If you are using a modem then make sure the phone line is also protected.

• FAQ's

• Tripplite protector

• GE protectors

Watt = N*m/sec = J/sec

None of these will work correctly without a GOOD ground. The older 3 prong to 2 prong AC adapters had a metal tab on the side where you could hookup a ground wire to a well casing, ground rod, etc.

Even if the device to be protected has only a 2 wire cord you still need a ground on the protector because the purpose of the protector is to send any spike or surge energy to ground before it can damage the equipment.