Frequently Asked Questions

This section of the site is designed to give the user more information about the dangers and costs of lightning and "dirty power" and how the correct use of surge protection equipment can minimise such dangers. The information is presented in the form of the questions most commonly asked of us regarding surge protection.

Q. Why do I need surge protection?

A. Because the electronic equipment you use at home and in the office is at risk of damage caused by lightning and "dirty power". This includes your computer and all the data stored on it, your home entertainment system (TV, DVD, VCR, stereo etc.), household appliances (washing machine, tumble drier, dishwasher etc.). In short anything you plug into the mains is at risk.

Q. How can lightning damage my equipment, and how likely is it to happen?

A. Lightning damage can be caused in 2 ways: direct and indirect strikes. A direct strike, as the name suggests, occurs when a bolt of lightning discharges its energy directly into a piece of equipment, the enormous amount of energy released will destroy any equipment which is not surge protected. Whilst the damage caused by direct strikes is usually catastrophic, direct strikes account for only 20% of damage to electronic equipment. The majority of damage is caused by the indirect effects of lightning. In fact a lightning strike up to a quarter of a mile away from your home, office or factory can seriously damage electronic equipment, computers and domestic appliances. The destructive energy from these indirect strikes is transferred into your premises by inductive coupling of the powerful magnetic field generated, or by capacitive or galvanic coupling. As a result when ever an electrical storm occurs in your locality, all of your electrical equipment is potentially at risk. Lightning damage is far more prevalent than you might think. Due to climate change and global warming, both the frequency and severity of lightning storms are increasing in the UK. As the lightning density map below shows, many areas of the UK suffer high lightning density, these areas are shown in red.

Contrary to popular belief lightning does strike twice. It is the local geographic and topological factors (eg. height, proximity to tall structures or trees etc.) which predominantly cause the original strike. Since these features rarely change, the chances of a repeat lightning strike are high. It is also not generally realised that when a building is fitted with a lightning conductor system to protect the building structure, that can make the transient problem within the building worse. As the heavy lightning current flows through the down conductor, a powerful fluctuating magnetic field can be generated. This induces damaging transients within computer, electrical and electronic equipment within the building.

Q. What is "dirty power"?

A. Dirty power is the name given to the contamination of the electrical mains supply by transients and electromagnetic and radio frequency interference (EMI / RFI). Transients are spikes or surges of voltage and current which exceed the normal operating levels and damage electronic circuitry and equipment. Typically transients result from heavy switching within or outside the building (e.g. a nearby substation). Heavy switching outside the building can occur due to the sudden breaking of a major load at a local substation. Equally the switching of heavy equipment within the building can result in "spikes" and "surges" of voltage or current. In a domestic environment, the switching of immersion heaters, cookers, night storage heaters can all cause damaging transients, which travel around the system.

Q. What is EMI / RFI?

A. Electromagnetic interference (EMI) and radio frequency interference (RFI) are as the name suggests types of radiated interference. Whilst this type of dirty power does not physically damage hardware it can corrupt data on equipment such as PCs. This interference can be common in the work place and home, the resulting loss of data can be time consuming and costly. This type of interference can be caused by the control and electronic dimming of fluorescent lighting, by radio transmissions, by mobile telephones and by rotating machinery.

Q. So, as long as I fit surge protection between the mains power supply and my equipment it will be safe?

A. That depends. As long as the equipment is connected only to the mains power supply, and you have surge protection on that circuit, then yes the equipment will be safe. However, if the equipment has a second connection (eg. a PC connected to a telephone line via a modem, or a television connected to an aerial) then the equipment is at risk from surges or transients which enter the equipment via this second connection. Simply fitting surge protection equipment to the powerline of a PC but not to the data-line connection of the modem, is akin to locking your front door to protect against burglary whilst leaving the backdoor wide open.

Q. How should I protect my equipment then?

A. Starting with circuits connected only to the power circuit, simply fit surge protection between each piece of equipment and the mains supply. For individual items (such as household appliances) Surgeplugs are an ideal solution. Where several pieces of equipment are located together Surgestrips provide quick and easy to fit protection. For equipment that has more than one connection (telephone line, TV aerial) the only way to provide complete protection is to fit surge protection between the equipment and each connection. For this type of application the Modem / Fax Protector and TV Protector can be used which offer protection for each service, in one plug-in unit.

Q. How does surge protection equipment work?

A. Surge protection equipment works in two basic ways. Firstly through the use of a combination of extremely fast acting electronic components, the transient is detected almost instantly, before it has a chance to damage the equipment. The damaging energy is then immediately diverted safely to earth where it is dissipated harmlessly.

Q. How much will it cost?

A. The simple answer is, not as much as the replacement cost of the equipment that could be destroyed without adequate surge protection. Insurance policies, service agreements and maintenance contracts typically treat lightning induced damage as an "Act of God" and exclude this type of damage from their cover. Under these circumstances the cost of installing surge protection equipment is a fraction of the potential cost of not doing so. As in most areas of industry the old adage "you get what you pay for" rings true, the Ethical Products Direct surge protection product range offers high grade protection at an affordable price, with the added security of a two year warranty. Whilst other surge protection products may be cheaper they often offer a lower grade of protection.