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Four Different Classes Of Lightning Arresters

Update:23 Aug 2019

A Lightning Arrester is a device, used on power systems […]

A Lightning Arrester is a device, used on power systems, which contains billions of electronic switches that divert lightning around sensitive equipment and protects them from damage of lightening and switching surges.

There are four different classes of arresters, including station class, intermediate class, distribution class and secondary class.

Station Class

Station class arrestors are typically used in electrical power stations or substations and other high voltage structures and areas.
These arrestors protect against both lightning and over-voltages, when the electrical device has more current in the system than it is designed to handle.
These arrestors are designed to protect equipment above the 20 mVA range.

Intermediate Class

Like station class arrestors, intermediate class arrestors protect against surges from lightning and over-voltages, but are designed to be used in medium voltage equipment areas, such as electrical utility stations, substations, transformers or other substation equipment.
These arrestors are designed for use on equipment in the range of 1 to 20 mVA.

Distribution Class

Distribution class arrestors are most commonly found on transformers, both dry-type and liquid-filled.
These arrestors are found on equipment rated at 1000 kVA or less.
These arrestors are sometimes found on exposed lines that have direct connections to rotating machines.

Secondary Class

Secondary class lightning arrestors are designed to protect most homes and businesses from lightning strikes, and are required by most electrical codes, according to, Inc., an electrical power protection company.
These arrestors cause high voltage overages to ground, though they do not short all the over voltage from a surge. Secondary class arrestors offer the least amount of protection to electrical systems, and typically do not protect solid state technology, or anything that has a microprocessor.