What Type Of Electrical Protection Device(s) Do I Need?

Electrical protection terminology in the 21^st century has many names. Lightning Arrester (LA), Surge Protector Device (SPD), Surge Arrester, Surge Suppressor, and Transient Voltage Surge Suppressor (TVSS) are the most common names used.

However, we can break down all of these names into two (2) groups.

Group 1 is Lightning Arrester/Arrestor (LA) which protects electrical transmission and telecommunications cables and insulation from lightning or a switching surge.

Group 2 is everything else. UL has defined this ground as surge protection devices (SPD’s). Most of the time they are only called SPD’s. An SPD protects the equipment from lightning and power surges.

Types of Lightning Arresters

• Road Gap Arrester
• Sphere Gap Arrester
• Horn Gap Arrester
• Multiple-Gap Arrester
• Impulse Protective Gap
• Electrolytic Arrester
• Expulsion Type Lightning Arrester
• Valve Type Lightning Arresters
• Thyrite Lightning Arrester
• Auto valve Arrester
• Oxide Film Arrester
• Metal Oxide Lightning Arresters

Classes of Lightning Arresters

• Station Class: Are available in ratings from 3 to 684 kV and have the highest fault current withstand capability.
• Intermediate Class: Are available in ratings from 3 to 120 kV and have a high fault current withstand capability.
• Distribution Class: Are available in ratings from 1 to 36 kV and they come in light-duty, normal-duty and heavy-duty ratings in the distribution class.
• Secondary Class: Are rated under 1000 V and are used to protect against secondary surges.

 Equipment that needs Surge Protection Devices (SPD’s).

• Ac Powered Equipment
  1. Type One
  2. Type Two
  3. Type Three
  4. Type Four component assembly
• Dc Powered Equipment
• Cable Television Coaxial Equipment (CATV)
• Closed Circuit Television Equipment (CCTV)
• Radio Equipment Cables
• Antenna Cables
• Ethernet Cables
• Telephone Land Line Cables
• Telephone Data Cables

From the information above it is plain to see that electrical protection devices require a lot of thought and studying before any purchase.

Most electricians, facility managers, and electrical supply houses have very limited knowledge about electrical protection. Each electrical protection device should be sized for the required electrical device and the desired voltage and surge protection levels needed to protect that piece of equipment from lightning or a power surge.

If a facility manager does not know what properly sized electrical protection devices are needed and wants to protect the electrical equipment in the building from lightning strikes and power surges a Subject Matter Expert (SME) in electrical protection needs to be involved. SPD’s come in many different protection levels and price points.