Domestic Lightning protection and Earthing

Lightning does strike twice, there is no way to define where or how it will strike, it is only possible to take precautions to limit the damage caused.

If you have a domestic house in a location where lightning is possible or has already happened, there are several things you can do to reduce the costs associated with a strike.

Ideal Scenario

Lightning protection key

1) Minimum of two ground rods (electrodes) at least 10 feet deep

2) Down conductors

3) Connect gutters or other grounded metals as required

4) Air terminals (lightning rods) located within two feet of outside corners of chimney

5) Antenna mast connected to roof conductor

6) Air terminals (lightning rods) spaced 20 feet apart along the ridges and within two feet of ridge ends

7) Dormers protected

8) Roof projections such as weather vanes or satellite dishes should be connected to lightning protection system

9) Surge protection devices installed at main electrical panel or meter

10) Surge protection devices installed at electronics in house

The protection is based on two basic principles, the strike is likely (not certain) to hit a metallic mass linked to a solid ground. Once the energy is largely directed to ground, Surge Protection devices will afford some protection to sensitive electronic devices.

However despite a lightning occurrence in the UK of more than six per year per square kilometre, direct hits are still the rarest form of domestic damage caused by lightning.

Lightning can damage equipment in your home from MILES away, a cloud to cloud strike 1 mile away will cause spikes and transients in your domestic wiring of sufficient energy to destroy your PC or television.

Many insurers of domestic properties are now recommending the fitting of surge protectors to any expensive electronic equipment. Unfortunately these recommendations have led to a flood of cheap protectors from abroad usually based on socket extension leads.

Some of these devices do not meet current minimum requirements for safety and a few are actually of such bad design that they INCREASE the risk of fire in your property during a lightning storm.

If you need help or advice for your installation call the experts now

A typical main incomer surge protection device (Zone C)

Surge protection device for smaller sub circuits (Zone B)

Surge protection device for sensitive single loads (Zone A)