Grounding elevator in buildings

Hi all,

I have a question about installing surge arrester between elevator rails and LPS. Is this common practice in your area/cuntry, and why is this a good idea?

I understand argument that it protects elevators electronic and motor from the surge coming from the ground as result of lightning discharge "near" the object. But...
Large buildings are almoust exclusively made from steel reinforced concrete or steel structure, which by itself + LPS is shielding object by Faradays principle, ensuring that any electromagnetic field (which is generated by lightning) cannot enter to objects interior. Elevator is in fact inside the object, so that is reason for my confusion.

Thanks in advance.

Hi Ivan,

Based on exp. elevator rails are grounded separate from the lightning protection system of the structure. This will protect the grounding system from any possible change of potentials within the structure. This change of potentials can create fire or explosion inside the structure where there is a possibility of conductivity.

Lightning is unpredictable. It doesn't mean that your structure is made from steel or reinforced concrete with LPS is now 100% secure from lightning damages.

Lightning hits according to the particles of environment where these environment particles itself can change instantly.

High rise structure has a greater possibility that it will be struck by lightning due to its components and location from the lightning source.

And according to NFPA NEC standards "lightning protection system is provided with the system grounding “down” conductor(s) located outside the hoistway within a critical horizontal distance of the elevator rails, bonding of the rails to the lightning protection system grounding down conductor(s) is required by NFPA 780, Standard for the Installation of Lightning Protection Systems. The requirements of 620.37(B) provide the necessary correlation for this bonding of the elevator rails to occur. Bonding prevents a dangerous side flash between the lightning protection system grounding down conductor(s) and the elevator rails. A lightning strike on the building air terminal will be conducted through the lightning protection system grounding down conductor(s), and, if the elevator rails are not at the same potential as the lightning protection system grounding down conductor(s), a side flash may occur. Generally, down conductors are installed vertically near the structure’s perimeter."

Hope it helps.

God Bless.

Best,
Neil