Lightning Rod, Air Terminal, Lightning Protection: What’s the Difference

Three terms, one system

An air terminal (air-termination) is the metal element at the top of a shaft that takes the lightning strike. The Ukrainian PUE (2026 edition) calls a device that takes the strike and carries its current into the ground a «блискавковідвід»; its parts are the air terminal, the down-conductor and the earth electrode. A lightning rod is the everyday name for it; in our catalogue it is a shaft or mast with an air terminal and an anchor cage for the foundation, that is, the supporting part of such a device.

These three parts together are what the PUE calls a «блискавковідвід». With the internal protection (equipotential bonding, separation distance) they make up the whole lightning protection system. So putting up a lightning rod does not yet protect a facility: the mast alone is only an air terminal with a supporting structure.

What external lightning protection consists of

• air terminal: the top of the system, where the strike lands;
• down-conductor: the conductor from the air terminal down to the ground; the steel shaft itself can take its place if the section joints are electrically reliable, the cross-section meets the standard and the design specifies it;
• earth-termination system: electrodes in the soil that disperse the current.

This is the external system under DSTU EN 62305-3. The same part of the standard also covers the internal one: equipotential bonding and separation distance. Protecting the power supply and electronics inside a facility from surges is treated separately, under part 4.

We make the shaft or mast with an air terminal and an anchor cage. The class of the system and the protection zone come from a calculation to the standard.

The terms and what they mean

The table lists the words used for the whole lightning protection system and its parts.

The terms differ in which part of the system they name: the «блискавковідвід» is the whole device, and a lightning rod in our catalogue is its supporting part. We have no separate product called «блискавковідвід»: we make a shaft or mast with an air terminal and an anchor cage.

Rod air terminals, masts and shafts

A rod air terminal is a vertical rod at the top of a mast or shaft. The article on protection-zone calculation gives a worked example for a single rod. Under DSTU EN 62305-3 earthing comes in two types: A, electrodes at the down-conductors, and B, a ring electrode around the structure or a foundation loop. More in the article on earthing of poles.

A bent multi-sided shaft works well as the supporting structure for an air terminal: neat, resistant to wind and corrosion. Lighting equipment or antennas can sit on the same shaft, and then the lightning rod also serves as a lighting pole or a telecom tower. This is how substations, production sites and warehouses, tank farms, filling stations and biogas plants are protected.

Height and protection zone

The height of a lightning rod is set by a protection-zone calculation. It takes into account the class of the lightning protection system (I–IV), the height and size of the facility and the layout of the masts. Our MO-series lightning rods on multi-sided shafts run from 5 to 40 m.

How the zone is calculated by three methods and what a single rod gives is shown in the article Protection zone calculation for a lightning rod. How to choose a lightning rod for a mast or tower is in Lightning protection of masts and towers.

Standards and inspection

Design follows the DSTU EN 62305 series. The old DSTU B V.2.5-38:2008 has been withdrawn, so a design based on it formally does not meet current standards: see Lightning protection standards.

After installation, continuity and earth resistance are measured. The inspection intervals and the records kept are described in the article Inspection and maintenance of lightning protection. Whether a steel mast can serve as the down-conductor itself is covered in A steel mast as an air terminal and down-conductor.

What to send so we can specify a lightning rod

Say what kind of facility it is, how large an area needs protecting and what height you have in mind. Add the wind region and whether the mast must also carry lighting or antennas. If a risk assessment is already done, give the class of the system.

Leave blank what you do not know and we will clarify. The protection zone is calculated by an engineer to the standard, and we propose the shaft design from your input data. All our products and the cost calculation are in the section Lightning rods, air terminals.