“A hammer of lightning” costs more than 20 million VND

Mr. Nguyen Kien, an elevator technician in Hanoi, said that in May 2022, he had to deal with a case where the elevator of a house in Dong Da district was completely damaged due to “electric shock” when lightning strike. The inspection showed that the 24V power supply, the inductor switch and the main board of the elevator were damaged and had to be replaced. The replacement of components cost more than 20 million VND and the elevator had to stop working for more than 1 week. This is not an isolated case when the elevator in Vietnam and around the world was damaged by lightning.

Electrical cabinet was struck by lightning after repair

Before that, within just 4 months, there were 2 times the elevator of an apartment building in Thu Duc district – Ho Chi Minh City was damaged by… lightning. Up to 6 elevators had problems and could not be operated. For the first time, the unit that supplied and installed the elevator for this apartment building repaired it within 2 months. The second time there was a problem due to lightning, it took 2 weeks to repair, the elevators were back in operation.

According to the Institute of Geophysics, Vietnam is located in the heart of Asian thunderstorms, one of three thunderstorm centers in the world with strong thunderstorm activity. Over the years, many buildings, power transmission lines, warehouses, post and telecommunications equipment, scientific research, electronics, etc. have been damaged by lightning, causing heavy loss of life and property.

Causes of elevators affected by lightning

It is estimated that each year, Vietnam suffers from 2 million lightning strikes during the thunderstorm season from March to October every year. Most of the localities were hit by lightning, in which many lightning strikes killed many people and caused great property damage.

When lightning strikes a building, even with protective measures in place, current can still flow into power lines that connect directly to a range of electronic devices. 220V voltage can increase abnormally to 3000 or 6000V, which can cause fire, damage to equipment inside the elevator… Especially the type of lightning that spreads when hitting a certain location, within a radius of 2 km from location of lightning strikes, all metal objects, electrical wires, data transmission lines will be affected by electromagnetic induction, there is a risk of damage.

Although the variation in current and voltage during a lightning strike lasts only a few microseconds, it can still destroy electronic components such as memory, processors, capacitors, and many other electronic components. Elevator is also a device with many electronic components, so damage due to lightning is completely possible.

A common lightning protection model for the building

In addition, when lightning strikes the power grid, if the circuit protection aptomat is not at the correct capacity, the electricity can “flash back” to damage electrical equipment and elevators. Construction experts note, even if the house has a lightning protection system, but if the design and construction process is not correct or the system does not have enough lightning protection devices to protect the elevator, the elevator may still be damaged by lightning. In addition, in an apartment building, the elevator system is an area with a lot of metal, so it will attract lightning to the elevator if the building’s lightning protection system is not guaranteed.

Solutions to protect elevators from lightning strikes

Many people think that just installing a grounding system for the elevator can prevent lightning for the elevator, which is a serious misconception. In fact, the elevator grounding system only helps to suppress electrical noise during the operation of the elevator, or helps to transmit electricity to the ground in case of high voltage leakage into the cabin, cabin door or landing door, electrical equipment on the machine room, ensuring maximum safety for users as well as technicians when working near the equipment.

The basic rule against the risk of lightning strikes is to prevent the energy of the lightning from affecting sensitive electronic equipment. For effective lightning protection, the lightning protection system needs to have enough components to determine the scope to be protected and to link specialized equipment including the grounding system and the surge protection device. Lightning protection solutions for elevators can be generalized into two steps.

First, make the grounding system.

The grounding for the elevator must have a resistance value of ≤ 4Ω. If during the construction of the pit, it is recommended to immediately put the grounding pile around the 4 corners of the elevator pit. In case the elevator pit has been completed, it can be arranged in the position of the open space outside as close to the elevator as possible.

Some lightning protection devices for elevators

Research shows that, if the grounding pile of the elevator is put too close to the grounding pile of the lightning protection system, when lightning strikes the lightning rod, it may affect the elevator. Therefore, the first measure to avoid lightning for the elevator is to keep the grounding pile of the elevator away from the grounding pile of the lightning protection system for a building with a distance of at least 6 meters.

The second is to install a lightning protection system or a lightning filter.

According to recommendations from the Institute of Geophysics, when designing a building, it is necessary to have lightning protection including direct lightning protection, surge protection and signal source lightning protection. In many lightning protection solutions for elevators, surge protection devices or SPD (Surge Protection Devices) are considered quite effective in protecting equipment when voltage rises suddenly, including important components of the elevator.

Lightning filter cabinet SF31500-480-135+50-AIMCB is priced at VND 383 million in Vietnam

Single-port SPDs can be connected in parallel, or two-port SPDs can be connected in series to the elevator’s electrical circuit. This surge arrester is designed to reduce electric shock caused by lightning strikes and transmit current to ground. SPD helps to reduce this overload voltage amplitude to a certain value which is not harmful to electrical switching devices as well as control devices.

There are many types of lightning protection equipment or lightning arrester. The protection equipment will provide better lift protection than the arrester, but the cost of the protection device is usually much greater than the arrester. For example, the lightning protection circuit breaker SF31500-480-135+50-AIMCB costs nearly 400 million VND while the surge arrester 1DR50KA-480-NE15-AIMCB is only about 5.8 million VND…

According to elevator experts, the installation of lightning protection devices for elevators is quite complicated and expensive, so consumers, elevator sellers and installers are “afraid”. But if you compare the terrible harm of lightning when it is transmitted to the elevator system, then surely the other costs and efforts are well worth it!