August 25, 2016
Surge Protection Device Installation
Dallas Homeowners Need To Know How To Install Surge Protection Device
An SPD must be able to change states quickly enough for the brief time a transient is present and to discharge the magnitude of the transient current without failing. The device must also minimize the voltage drop across the SPD circuit to protect the equipment it is connected to. Finally, SPD function should not interfere with the normal function of that circuit.
Board type B class and C class surge arresters must be connected in parallel to the system.
Correct Installation of Hard-Wired Surge Protective Device
It is important to understand the difference between lightning protection systems and SPDs. A lightning protection system’s purpose is to channel a direct lightning strike through substantial current-carrying conductors to earth, thus saving structures and equipment from being in the path of that discharge or being directly struck. SPDs are applied to electrical systems to provide a discharge path to earth to save those systems’ components from being exposed to the high-voltage transients caused by the direct or indirect effects of lightning or power system anomalies. Even with an external lightning protection system in place, without SPDs, the effects of lightning can still cause major damage to components.
It is very important to follow the manufacturer’s installation instructions. Pay particular attention to fuse or breaker requirements and lead lengths.
It is also important that the electrical distribution system be grounded and bonded per the National Electrical Code. Failure to do so may result in damage to the surge protective device (SPD).
The performance of parallel-connected transient voltage SPDs is affected by the connecting leads. Both the wire size and length used to connect the SPD will influence its performance.
SPD is designed to limit transient over voltages of atmospheric origin and divert current waves to earth, so as to limit the amplitude of this overvoltage to a value that is not hazardous for the electrical installation and electric switchgear and control gear.
Surge Protection Devices for PV Installations
Because PV installations must be designed to provide full exposure to the sunlight, they are highly vulnerable to the effects of lightning. The capacity of a PV array is directly related to its exposed surface area, so the potential impact of lightning events increases with system size. Where lighting occurrences are frequent, unprotected PV systems can suffer repeated and significant damage to key components. This results in substantial repair and replacement costs, system downtime and the loss of revenue. Properly designed, specified and installed surge protection devices (SPDs) minimize the potential impact of lightning events when used in conjunction with engineered lightning protection systems.
The Importance of SPDs
Aside from the consequences of direct lightning strikes to the arrays, interconnecting power cabling is very susceptible to electromagnetically induced transients. Transients directly or indirectly caused by lightning, as well as transients generated by utility-switching functions, expose electrical and electronic equipment to very high overvoltages of very short duration (tens to hundreds of microseconds). Exposure to these transient voltages may cause a catastrophic component failure that may be noticeable by mechanical damage and carbon tracking or be unnoticeable but still cause an equipment or system failure.