Surge Protection

What is a Surge?

Surges are high voltage peaks which only last micro seconds; these can also be called transient surges or transient overvoltages, these are commonly caused by lightning strikes but can also be caused by switching equipment in both commercial & industrial applications.

Today’s sophisticated electronic equipment & micro electrical components are extremely sensitive. In many cases they are also networked throughout the building or company, so should you experience a surge or overvoltages and one part of the system is damaged the whole network system will fail. The consequential losses incurred from this type of shut down, such as lost production can be extremely expensive.

Surge Protection Devices

The answer is to fit an appropriate surge protection device also known as a surge arrestor. A guide below gives a brief overview.

Type 1 Surge Arrestors – T1

It is now mandatory to fit a surge or lightning current arrestor on main incoming panels which are in buildings with external lightning conductors fed by an overhead line.  (New Standard BSEN62305-4 1st Sept 2008 & 17th Edition Wiring Regulations Amendments 1st Jan 2012).

This Type of surge arrestor is called a Type1 surge arrestor; however for little extra cost you may be able to fit a combined T1 + T2 + T3 arrester as this gives additional surge protection.

Type 2 Surge Arrestors – T2

For panels in buildings without external lightning conductors and fed by underground cables a T2 surge arrester is sufficient. Sub-distribution boards or local control panels more than 10 metres from the main incomer and not feeding external circuits then a Type 2 surge arrester can be used.

Type 3 Surge Arrestors T3

Sensitive electronic equipment , micro electrical components & sub-circuits such as, Fire Alarm Panels, Intruder Alarms or computer control systems such as a programmable logic controller (PLC’s) which are fitted more than 10 metres from the last surge arrester should have a T3 surge arrester fitted at the panel or equipment to be protected.

Type T1+T2+T3 Combined Surge Arrestors

Circuits & Panels feeding external systems such as CCTV, flood lights or car parks, should have a combined T1+T2+T3 surge arrester fitted as standard.

Andrews Electrical Ltd can offer experienced advice about protecting your vital electrical systems from surge damage. We would be happy to discuss your individual requirements and provide an estimate upon request.