Surge Protection Devices for Buildings

Surge Protection Devices (SPDs) are a requirement of the 18th Edition Wiring Regulations and are designed to protect cables, switchgear and electrical equipment within a building by limiting transient overvoltages caused by atmospheric conditions and switching events and diverting current waves safely to earth.

BS 7671:2018 IET Wiring Regulations Eighteenth Edition states that: “Protection against transient overvoltages shall be provided where the consequence caused by overvoltage could result in: i. serious injury or loss of human life ii. significant financial or data loss”

And also highlights 'Safety Services' defining them as “An electrical system for equipment provided to protect or warn persons in the event of a hazard, or essential to their evacuation from a location”

Type 1/2/3 Surge protection Devices

Coordinated Type 1/2/3 surge protection throughout a building is recommended for optimum protection. Type 1 SPDs fitted at the main incoming supply provide protection against surges caused by direct lightning strikes. Type 2 SPDs protect LV installations from the effects of indirect lightning strikes and switching events. And Type 3 SPDs protect critical or sensitive equipment, such as safety systems, IT, telecomms and data equipment from damage caused by let-through voltage from upstream SPDs in the event of transient overvoltages.

For advice on how to select the right Surge Protection Solution for your building or project, contact our technial team This email address is being protected from spambots. You need JavaScript enabled to view it.

T1 - Type 1/Class I Surge Devices

A Type 1/Class I device should be fitted at the incoming supply of any building fitted with a steel frame or Lightning Protection System (Faraday Cage), where power is supplied by overhead cables or where the building is in a remote area. The Type 1 SPD protects electrical installations against the catastrophic effects of a direct lightning strike. Where a Type 1 SPD is fitted at the incoming supply, Type 2 protection 'downstream' may be required to protect distribution boards and sensitive electrical equipment from damage caused by let-through voltage. Type 1 SPD is characterized by a 10/350 µs current wave. ..

T2 - Type 2/Class II Surge Devices

A Type 2/Class II device should be Installed at the main incoming supply (Unless the application requires Type 1) and at any electrical switchboard more than 10 metres from the upstream SPD, to protect against overvoltages caused by atmospheric or switching activity. Critical or sensitive equipment may require a additional protection from a Type 2 or Type 3 device. Type 2 SPD is characterized by an 8/20 µs current wave. ..

T3 - Type 3 SPD Class III Surge Devices

Type 3 SPD Class III Surge Protection Devices have a low discharge capacity. They should be used as a supplement to Type 2 Surge Protection Devices and in the vicinity of critical or sensitive equipment such as servers or computer equipment, hi-fi or home cinema, CCTV, intruder or fire alarms, safety equipment, CNC-controlled machinery, telephone systems, sockets and lighting. Type 3 SPD is characterized by a combination of voltage waves (1.2/50μs) & current waves (8/20μs). ..

T1- Type 1/Class I All-Mode Protection

A range of bespoke all-mode/full-mode Class I surge arrester enclosures designed to provide the highest level of protection for the incoming supply and main switchboards in large structures located in high lightning exposure areas. ..

Electromagnetic Interference (EMI) Surge Filters

Electromagnetic Interference EMI and Radio-Frequency Interference RFI is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.The disturbance could degrade the performance of a circuit or even stop it from functioning completely. In the case of a data path, these effects can range from an increase in error rate to the total loss of data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares and auroras. EMI affects AM & FM radio signals, mobile ..

Protective Equipotential Bonding

Equipotential bonding EPB describes the process of electrically connecting metalwork and conductive elements of a building to ensure equal potential voltage throughout the application. This ensures that in the event of a nearby lightning strike, potentially hazardous sparking or flashover of the current to conductive parts such as metal pipes, earthing and cables within the structure is avoided, thus reducint the risk of damage to equipment and personal injury. This range of Equipotential bonding devices are designed for use where the distribution wiring enters the building, to incoming services and earthing systems that cannot be directly bonded to earth during ..