It is unfortunate, but a fact of life, that PCs, computer related products, process control and data communications equipment can be damaged by high-voltage surges and spikes.

These surges and spikes are most often caused by lightning strikes but can also be triggered by power cuts produced by, for example, load shedding. A lot can be done as far as protection is concerned; however, it is best to begin by describing the magnitude of the threat from which one needs protection.

The first stroke of lightning during a thunderstorm can produce peak currents ranging from 1000 - 100 000 Amperes with rise times of one microsecond. It is hard to imagine, let alone protect against, such enormous magnitudes. Fortunately, such threats only apply to direct hits on overhead lines, which is a relatively rare phenomenon. More common is the induced surge on a buried cable. When lightning hits the ground, it creates a ripple effect similar to a drop falling into water. These ripples can travel up to five kilometres, making their way through buried cable which can cause damage to unprotected equipment.

Another cause of harm to equipment comes from power cuts or power surges. Electricity can be described as a river which flows into different channels. When one channel is closed, the water must still go somewhere, causing some of the other channels to reach peak levels.

The best protection

A) For buildings/businesses with server rooms

Companies simply cannot afford to not pay attention to high-voltage surges and spikes. To this end, Netshield offers a range of protection equipment, including the following, for the server room:

The NLMAINUNIT-2U-E and NLMAINLITE-2U-E

The NLMAIN-range offers protection to X21 Telkom lines and also has an internal SNMP device that enables the user to connect to monitoring software. There are two extra slots available to either expand to X21, Ethernet or E1. If still further expansion is needed, there are chassis that can be added to accommodate further protection for X21, Ethernet and E1.

The NLMAINLITE-2U-E has only one low power meter probe containing eight kettle (IEC) connectors. It provides 16A max and is suitable for smaller environments.

The NLMAINUNIT-2U-E has one low power meter probe containing 16 kettle (IEC) connectors giving out 16A max, as well as two high power meter probes, each providing 32A max. These devices are suitable for larger environments.

B) For field offices/SOHO/ home environment

The NLSP surge protection range consists of standalone units available to protect general equipment and Telkom lines. These units each have one plug point where the user can add a short extension lead with additional plug points if more than one device needs protection, as long as the total does not exceed 16A. An important additional feature is the inclusion of technology that detects when damage occurs, which is then visually indicated through an LED light. This gives users the advantage of knowing when the unit has taken a fatal strike and needs to be replaced.

The range consists of:

• NLSP-M-M: To protect equipment such as a PC, Hi-Fi or TV
• NLSP-ADSL-M: To protect internet access and telephone lines
• NLSP-E1-M: To protect all G703 lines and PABXs
• NLSP-ETH-M: To protect all network applications including 10/100/1000 and POE protection in one unit.

For enquiries on any of these products, contact Netshield on 086-111-4428 or 012-841-0320, or visit www.netshieldsa.com.