About Us


OTOWA does not allow lightning surges to enter.

We protect people, environment and our society.

In today’s modern society, where IoT technology is expanding, lightning strikes are increasing as a result of extreme weather condition caused by global warming. In addition, the threats of lightning strikes on society as a whole are increasing. OTOWA is expanding its range of activities to protect people, environment and our society from the dangers of lightning.

Solving the problemregarding lightning

Our vision is to create a safe and secure society that is not afraid of the threat of nature known as "lightning".
We will make such a wish come true with our advanced lightning protection system.
Here at OTOWA we consider lightning protection to be a system and we propose the best lightning protection for all projects.
We thoroughly investigate the lightning intrusion route and the damage, then we explore the best optimal countermeasures in all processes from the design to enforcement and maintenance.

Technology for people around the world

With trust and cooperation, we OTOWA are taking on new challenges in regards to different lightning issues from each country, together with our partners around the world. For instance, we have provided technical assistance to talented people from Rwanda, a country that has some of the most frequent thunderstorms in the world. When it comes to lightning strikes and we operate across borders.

OTOWAmeets all your needs.

We prepare a variety of products

OTOWA is a manufacturer that specializes in lightning protection.
We coexist with lightning while specializing in understanding lightning so that we can build a society that has minimal lightning damage.

We prepare a variety of products beginning with the arrester for the DH class, railways and a SPD for offices, factories and domestic use.
Our products can be customized following your order and request, so please feel free to contact us.

We consult on all lightning countermeasures.

Lightning countermeasures should be taken seriously for the entirety of all facility.

Countermeasures against lightning differ depending on the various conditions such as the location of the building and electrical wiring.

Lightning countermeasures are one of the most important aspects of risk management.

It is important to design suitable lightning countermeasures that weigh the risks of lightning damage and the costs of lightning countermeasures.

  • The risks...frequency of lightning and the potential damages and losses to important facilities.
  • The costs for lightning countermeasures...installation costs for SPDs etc…

OTOWAThe proposals for lightning countermeasures from OTOWA group

  • NIP engineering...Lightning countermeasures for building equipment and solar energy maintenance
  • GEO TECH...A specialist of earthing.
  • HASEGAWA...Creator of electrical safety systems
  • OTOWA...Specializes in lightning protection

OTOWA group will work together to implement a system that protects the customer’s equipment.

World's best lightning test equipment

We can reproduce 220kA direct lightning

We use the world's Top Class lightning test equipment to evaluate and develop our products independently.
Our track record is highly evaluated, and we also receive entrusted tests results which is based on the standard of JIS and IEC.
The test equipment, which is one of the largest in the world, was designed and manufactured by OTOWA.
A 220kA direct lightning current can be artificially created.

Lightning technology center Lightning impulse voltage test equipment

SPD Features

The SPD contains at least one nonlinear component with the function of limiting transient overvoltages and diverting surge currents. Due to the characteristics of the nonlinear component, the SPD can protect equipment from surge events by limiting transient overvoltages. At normal operating supply voltages, the SPD is highly resistive and is equivalent to an insulator. However, when a transient overvoltages such as lightning surges occurs, the nonlinear component’s resistance decreases making it equivalent to a conductor which then diverts the surge current to ground. At this time, the SPD sends a lightning surge current to the ground and suppresses the lightning surge voltage. After it suppresses the lightning surge, it immediately returns to a high resistance state, in order to block follow current due to the supply voltage.

  • SPD: Surge Protective Device
  • SPD Aliases : Lightning arresters, arresters, surge protectors, etc.

Nonlinear elements include MOV (metal oxide varistor), GDT(discharge tube with gas), ABD(avalanche break down diode), TSS (surge protection thyristor), etc.

SPD Features

OTOWApursues the ultimate components and devices

The quality recognized by the world's customers

OTOWA develops and manufactures metal oxide varistors, the key component of the lightning arresters, by our own independent technologies. Various parts and devices are produced using the knowledge accumulated over the past half century and the auto-producing facilities of our own designs. Even through the most severe quality control recognized in the world, we provide high-performance, high-quality parts and devices. OTOWA's metal oxide varistors are highly rated for their quality and are employed in world class surge arresters.