Flameproof Junction Box | Aluminum Alloy Casting | Zone 1 & Zone 2 Compatible

In locations where flammable gases or vapors may exist, such as chemical plants and oil refineries, there is a risk that sparks generated by electrical equipment could become an ignition source.

Flameproof junction boxes are used in these hazardous areas for relaying and branching wires and cables. Shimada Electric's products use aluminum alloy castings and support wiring and connections in Zone 1 and Zone 2.

In Japanese-affiliated factories and plants that have been operating in Thailand for many years, aging equipment often requires replacement, expansion, or modification. During equipment upgrades, it is important to review existing explosion-proof equipment to ensure it meets the current installation environment and required explosion-proof specifications. Shimada Electric has acquired "ATEX" and "IECEx" international explosion-proof certifications, which are required for plants in Thailand.

Nippon Denka Kogyosho (Thailand) Ltd. handles Shimada Electric's explosion-proof boxes for factories and plants in Thailand. Please feel free to consult with us regarding product selection and specifications.

Table of Contents

• Shimada Electric's flameproof junction boxes
• Flameproof structure and supported standards
• Main product specifications
• Selecting inlets and terminal blocks according to wiring specifications
• Precautions for installation and maintenance
• FAQ
• Keywords for understanding this article

■ Shimada Electric's flameproof junction boxes

Shimada Electric's flameproof junction boxes are used for relaying and branching insulated wires and cables, or connecting cables together.

The enclosure is made of aluminum alloy casting. It has excellent corrosion and salt resistance, and its weight is reduced to about one-third of conventional cast iron or steel boxes.

The lighter weight helps to reduce the burden of transportation and on-site installation work, making it suitable for new construction, expansion, and renovation projects in oil refineries, chemical plants, power facilities, and utility tunnels.

They can be used for connecting cables and wires in hazardous areas of Zone 1 and Zone 2.

■ Flameproof structure and supported standards

A flameproof structure is an explosion-proof design that withstands the explosion pressure even if explosive gas enters the enclosure and causes an internal explosion, thereby preventing the propagation of the flame to the surrounding explosive atmosphere.

In addition to Japanese explosion-proof certification (TIIS), Shimada Electric's flameproof junction boxes also feature a lineup of models with ATEX and IECEx certifications for the overseas market.

The main explosion-proof specifications of the representative STH series are as follows:

Models such as STH-1, STH-3, STH-5, and STH-6 are available with ATEX and IECEx certified specifications. They can be selected according to the explosion-proof specifications required by the equipment or project being installed.

In addition, STH-1 and STH-3 can also support the hydrogen explosion-proof d3a specification. For the hydrogen explosion-proof specification, the inlet is machined with a Class A PF thread and used in combination with a compatible flameproof cable gland.

Since the required explosion-proof structure, gas group, temperature class, and certification vary depending on the installation location and equipment conditions, it is important to select the product after confirming the operating environment.

■ Main product specifications

The main specifications of the representative STH series are as follows:

In addition to standard terminal blocks, terminal blocks with different rated currents and wire sizes can be incorporated depending on the wiring capacity.

Multiple product sizes are available, allowing you to select based on the required number of terminals, wiring capacity, and installation space.

■ Selecting inlets and terminal blocks according to wiring specifications

For flameproof junction boxes, you can specify the size, quantity, and layout of the inlets according to the wiring to be installed.

For domestic specifications, they are usually machined with a Class B PF thread, and can also accommodate a Class A PF thread if necessary. Additionally, NPT thread machining is available for the Exd IIB specification.

For ATEX and IECEx certified specifications, you can choose from M threads, NPT threads, G threads, etc., depending on the model and certification conditions.

Inlets can be specified for each side of the junction box in sizes and quantities tailored to the piping design. Terminal blocks can also be selected according to the required rated voltage, rated current, number of terminals, and compatible wire sizes.

Since inlet machining is performed after the specifications are confirmed, the position and size must be checked before placing an order. Once an order is accepted, changes to the inlets cannot be made, making it crucial to select specifications that align with your wiring plan.

Please consult with us regarding specifications tailored to the conditions of your installation site and the connection methods with existing equipment.

■ Precautions for installation and maintenance

Explosion-proof equipment must be used appropriately, taking into consideration not only the explosion-proof performance of the product itself but also the installation method, wiring, and maintenance procedures.

Particularly for explosion-proof equipment, it is vital to select the product after confirming the hazardous area classification of the installation site, the target gases, and the required explosion-proof structure.

Please feel free to consult with us regarding product specifications and installation conditions.

※For more details, please download the PDF attached to this article or contact us via the form at the bottom of the page.

■ FAQ

Q1. Can it be used in Zone 1 and Zone 2 hazardous areas?
A1 : Yes. Shimada Electric's flameproof junction boxes can be used for connecting cables and wires in Zone 1 and Zone 2 hazardous areas. However, since the appropriate model varies depending on the target gas, required explosion-proof rating, temperature class, etc., it must be selected according to the installation conditions.

Q2. Can I specify the size and layout of the inlets according to the wiring?
A2 : Yes. You can specify the size, quantity, and layout of the inlets according to the wiring to be installed. Regarding thread standards, there are models that support PF, NPT, M, and G threads depending on the specifications. Terminal blocks can also be selected according to the required current capacity and wire size.

Q3. Are there products that support ATEX and IECEx certifications?
A3 : Yes. The STH series includes models that have acquired ATEX and IECEx certifications. Since the required certifications and explosion-proof specifications vary depending on the requirements of the equipment or project being installed, we will select the appropriate model after confirming the operating conditions.

■ Keywords for understanding this article

• Flameproof structure : An explosion-proof design constructed to withstand the pressure of an explosion occurring within the enclosure and to prevent the flame from propagating to the external explosive atmosphere.
• Hazardous area : A location where an explosive atmosphere could potentially occur due to flammable gases or vapors.
• Zone 1 : A hazardous area where an explosive atmosphere is likely to occur under normal operating conditions.
• Zone 2 : A hazardous area where an explosive atmosphere is unlikely to occur under normal operating conditions, and if it does, it will only persist for a short period.
• IP66 : A protection rating indicating the enclosure's dust and water resistance. It signifies protection against the ingress of dust and protection against powerful water jets.
• ATEX/IECEx : Certification systems related to explosion-proof equipment used in explosive atmospheres. The required certifications and specifications vary depending on the installation country, equipment, and project.

※For more details, please download the PDF attached to this article or contact us via the form at the bottom of the page.