Equipment Protection

In common with electricity systems worldwide, ESB Networks' system is subject to unavoidable variations in voltage. These may interfere with the effective functioning of sensitive appliances or equipment.

Some of the Causes Voltage variations can occur for a number of reasons:

• Lightning
• Accidental damage
• Storm damage to overhead lines
• Vehicles striking poles or equipment
• Animals and birds coming in contact with lines
• Interference from construction and excavation activities
• Equipment failure on the ESB Networks' system
• Very large or frequent variations of load in your own or nearby installations
• Disturbances generated by your own or another customer's equipment
• Trees in contact with overhead powerlines

Today's electrical equipment can be highly sensitive to even split-second interruptions or to voltage disturbances and variations. Appliances that can be affected include:

Voltage variation is controlled as far as possible by the careful design and operation of the ESB Networks' system. However, it is not technically feasible to maintain an absolutely steady supply voltage at all times. Therefore it is important that you adhere to the guidelines given in Section 4(b) and 4(i) of ESB Networks' General Conditions of Supply in relation to selection and maintenance of your electrical equipment and installations.

The effective and safe utilisation of electricity depends on the quality of your electrical installation as well as upon the nature of the supply delivered by ESB Networks. With the help of your registered electrical contractor, you should ensure that your supply is correctly connected and that your installation and equipment are suitable for that supply. You should also select equipment that remains capable of functioning and is adequately protected from unavoidable disturbances.

Some voltage variations are referred to as surges. The vast majority of these surges are generated within an electrical installation and can be triggered internally or externally.

For example switching on and off a fluorescent light can generate a substantial surge. Another type of surge can be caused by lightning. This is a much more powerful surge and requires specific equipment to control the high energy involved. The equipment used for controlling surges is called a Surge Protection Device or SPD for short. It is important to note that a switching surge SPD generally will not provide protection against a surge caused by lightning.

Considering that the majority of voltage disturbances come from within your own electrical installation, it makes good sense to protect your electrical installation and equipment from such disturbances.

There is no substitute for the level of protection afforded by an electrical installation designed by an expert in this field and correctly installed by a registered electrical contractor. However some simple steps can be taken to reduce or even eliminate the effects of voltage surges.

The first and easiest place to start is by installing individual surge protected circuits/leads, as illustrated below. These should be installed on expensive/ sensitive electrical equipment
(see earlier list).

« An example of a Surge protected Lead.

Surge protected leads are widely available from electrical retailers and normally (but not always!) the more you pay the better the protection. Avoid purchasing 'bargain' SPD's... remember that if they fail to work, your equipment may be damaged. Some manufacturers offer warranties (with conditions) in the event that connected equipment is damaged due to a failure of their product.

TWO IMPORTANT POINTS TO REMEMBER:

1. Don't overload extension leads
2. There are various qualities of surge protection

Installations, equipment, fuse/mcb boards and wiring must comply with the ETCI National Rules for electrical installations and should be checked at least every 10 years or whenever an alteration is made. This can be done by an electrical contractor who is registered as a member of a recognised regulatory body.

ESB Networks' staff are constantly working to minimise interruptions and quickly restore power when problems occur. Over the four years up to 2010 we are investing in excess of €2.5 billion in reinforcing and renewing our networks.

Some disturbances such as those caused by severe weather are uncontrollable. However, for those situations within our control, a number of measures are taken to maintain power quality and improve reliability. These measures include:

• Regular maintenance to ensure that our system functions as intended.
• Installation of lightning and fault protection systems throughout the ESB network.
• Replacement of obsolete and defective equipment.
• Provision of clear information on the approximate location of our underground cables to those excavating roadways, footpaths, streets, srl. (Note: All contractors involved in such excavations should use cable detection equipment.)
• Tree trimming to keep branches away from power lines.
• Installation of guards to prevent animals from making contact with ESB Networks' equipment.

Finally, international standards are under constant development to ensure that the equipment available to you and other customers neither generates excessive disturbance nor is unduly sensitive to disturbance or damage. ESB Networks helps in the development of these standards.