Junction Box Types

Faced with a wide variety of junction boxes, are you confused about how to choose? Different junction boxes have different uses and purposes. This article breaks down different junction boxes for you from material, shape and function. Through this article, you can better comprehend the types of junction boxes that suit your electrical appliance needs.

What is a junction box?

접속함 can also be called jbox or electrical box. It is a standardized enclosure used in electrical wiring systems to accommodate, protect wire connections and provide installation support for switches, sockets and other equipment.

The junction box can prevent accidental contact with wires, prevent the intrusion of external metal objects or beyond from causing short circuits, and protect the internal wires from mechanical shock, compression and pulling.

Junction boxes with different IP protection grades can also achieve dust-proof and water-proof effects. Different materials can also achieve the effect of anti-corrosion.

Types of Junction Box

By Material

Plastic Junction Box

재료: Common types include PVC junction boxes, ABS junction boxes, and PC junction boxes.

특징: Insulation is one of the most significant safety features of plastic junction boxes. Additionally, it also has good corrosion resistance. Even if you install it in a damp place, you don’t need to worry that it will rust. Moreover, lightweight plastics are easy to cut and drill holes in. If you want to achieve a higher level of water and dust resistance, you can do so by adding a sealing ring.

장점:One of the notable advantages of plastic junction boxes is their high cost performance, as both raw material and production costs are lower. The lightweight junction box is also easier to handle and install.

What’s more, for some corrosive environments such as chemical plants and laboratories, high-grade plastics are an ideal choice. Moreover, it will not rust in a humid environment and can ensure insulation safety, providing a great guarantee for basic safety.

응용 프로그램: Plastic junction box can be used for concealed switches, socket boxes and lighting wiring in the vast majority of residential and commercial buildings. If supplemented with a sealing cover plate, it can also be used in slightly damp rooms such as bathrooms and kitchens. Besides, some sewage treatment plants and chemical laboratories can also apply it.

금속 접합 상자

재료: The manufacturing materials for metal bonding are usually galvanized steel, 304 stainless steel or 316L stainless steel, and aluminum alloy.

특징:Metal junction boxes conduct electricity, so you need to connect them to the grounding system to avoid the risk of leakage. Metal materials have higher mechanical strength and possess the ability to resist impact, pressure and deformation.

장점:The metal junction box can withstand heavy pressure, impact and guarantee that the internal links are not physically damaged. Besides, metal also has excellent fire resistance， becoming a standard feature in commercial and public buildings.

In addition, metals can provide electromagnetic interference shielding and are conducive to dissipating the heat generated by large currents. It can also withstand higher temperatures and has an extremely long service life.

응용 프로그램: You can apply it in industrial or commercial buildings such as factory workshops and shopping malls.You can also install it in places with high security requirements, such as computer rooms, equipment rooms and other areas where it may be hit by equipment. Metal junction boxes are also used in some harsh outdoor environments, electromagnetically sensitive or dangerous areas.

By Shape

라운드 팬 접합 상자

특징: Round pan junction boxes are typically round in shape but shallow in depth. Their internal volume is relatively small, making them suitable for installing lightweight equipment.

장점: It can be installed on walls or in narrow ceiling spaces. When the installation depth is limited, the round pan junction box is the only solution. And its installation is very simple and it is a device capable of withstanding light equipment.

응용 프로그램: You can attach the round pan junction box with long screws directly to the beam as a reinforcement base for the ceiling fan. Or use it to install it as a ceiling light junction box. On a wooden wall where grooves cannot be made, you can use it to install a simple lamp or switch.

표준 일반 접합 상자

특징: Standard regular junction boxes are usually square or rectangular, with varying depths and sizes, and can adapt to the requirements of different wire capacities. It is usually made of either metal or non-metal.

장점: The standard regular junction box can be perfectly matched with the vast majority of switch and socket panels on the market. And it is easy and quick to install.

응용 프로그램: You can install it on all the switches and sockets on the interior walls. It is also the standard electrical point for residential and commercial buildings. It can also be used as a universal junction box as a cable convergence point for power distribution.

표준 사각형 접합 상자

Features: The Standard square junction box has a larger cubic capacity and can provide sufficient empty space for complex wire connections.You can install partitions inside the large standard square junction box to divide the junction box into two chambers. You can also install one or more junction box covers on the front to achieve multi-functional usage.

장점: It can provide plenty of space for connectors and conductors. Moreover, this is also more conducive to subsequent wiring, inspection and subsequent modifications. And it has high application flexibility and can provide a variety of junction box covers.

응용 프로그램: It is capable of installing more than two switches or combined devices in parallel. And it can also create branch circuits. Its robust structure and safety make it more widely used in residential areas and commercial places with complex wiring. You can install it into a socket or switch and supplement it with a plaster ring.

Standard Round/Octagon Junction Box

특징: The octagonal electrical junction box and the circular electrical junction box have almost the same function and size. These junction boxes are equipped with adjustable metal fasteners.

장점: Adjustable metal fasteners can make the installation of ceiling equipment more stable. And it can also well support the weight of ceiling lamps and chandeliers that do not exceed fifty pounds. Additionally, this type of connector can be directly installed on the wall without cutting holes.

응용 프로그램: Standard circular or octagonal junction boxes can serve as installation points for all ceiling lamps. Therefore, another name for it is the ceiling light junction box. The junction box with the rated fan marking can be used to install ceiling fans.

By Design and Functionally

천장선풍기 접합 상자

특징: Ceiling fan junction boxes can be either circular or octagonal. They are usually made of metal and equipped with heavy-duty suspension brackets or screw holes, allowing them to be installed on the load-bearing structure of the building or on dedicated ceiling fan brackets.

장점: Its notable advantage is safety. The ceiling fan junction box has extremely strong load-bearing and seismic resistance capabilities and a high safety level.

응용 프로그램: It is suitable for the installation of ceiling fans, chandeliers or other suspended electrical appliances in residential or commercial areas.

Weatherproof Junction Box

특징: Weatherproof junction boxes are usually made of UV-resistant engineering plastics or corrosion-resistant metals. Excellent materials can make sure that the junction box does not become brittle or discolor after long-term exposure to sunlight.

It can withstand extreme temperatures for a long time and has good chemical corrosion resistance. Besides, it is also equipped with a tight sealing structure, including a cover plate, sealing rings, etc. Its protective capability is mainly precisely determined by the protection level.

장점: It can prevent short circuits and leakage caused by moisture, guaranteeing the safety of electrical equipment. Excellent anti-aging and anti-corrosion properties can extend the service life of electrical equipment and reduce the risk. Rich sizes and shapes can adapt to different application requirements.

응용 프로그램: It can be applied to power or electrical control areas such as outdoor lighting systems, building peripheral equipment, irrigation systems or parking lots.

Explosion-Proof Junction Box

특징: The explosion-proof junction box has an exceptionally strong heavy-duty enclosure.These enclosures are usually made of a strong metal such as cast iron,스테인리스 스틸, which effectively prevents internal sparks from igniting the external environment.

장점:  Explosion-proof junction boxes are mandatory equipment for ensuring the safety of life and property. The enclosure, which is impact-resistant, corrosion-resistant and has high mechanical strength, has an extraordinary service life. The precise mechanical structure and high-quality materials guarantee that the explosion-proof performance remains stable.

응용 프로그램: It must be applied in hazardous environments where flammable gases and dust exist, such as oil refineries, gas stations, oil tank areas,  metal powder production workshops and underground coal mines,etc.

Tips:The product must have the mandatory explosion-proof certification of your region. Products without certification are strictly prohibited from use. Moreover, the explosion-proof junction box needs to be used in conjunction with explosion-proof lamps and cables to form a complete explosion-proof circuit.

야외용 접합 상자

특징: Outdoor junction boxes are specially designed to protect electrical connections from factors such as water,dust,and UV rays. The materials of outdoor junction boxes are usually non-metallic plastics or coated metals, which can achieve excellent corrosion resistance and temperature resistance.

Electrical junction boxes for outdoors are usually equipped with gaskets and other components to guarantee the sealing performance of the product. And the protection level will be evaluated based on the ability to resist rain, ultraviolet rays, etc.

장점: It can protect electrical appliances from moisture and other harsh outdoor factors, prevent corrosion, and ensure electrical safety. It can withstand long-term harsh outdoor environments and has a long service life.

응용 프로그램: Outdoor junction boxes are suitable for the connection of electrical equipment installed outdoors, including all building exterior walls, street lamps and outdoor surveillance cameras,etc.

2/3/4-Gang Junction Box

특징:A multi-gang junction box is an electrical junction box that integrates multiple standard compartments into one unit.The enclosure usually has prefabricated movable partitions inside, which can physically isolate the cables of different circuits and also provide support points for the set screws in adjacent compartments.

장점: The multi-gang junction box can integrate all the devices into a continuous enclosure achieving a compact and minimalist appearance. The integrated structure can achieve concentrated functions and simple appearance. Besides, the installation is simpler and more efficient, and it is also convenient for maintenance and repair.

응용 프로그램: Multi-gang junction boxes are almost applied in all situations where electrical control points need to be centrally arranged, and they are also the mainstream choice in modern electrical design. In the residential space, it can centralize the switches of various lamps. In commercial office spaces, it can serve as a control switch for a variety of electrical appliances.

Choose the Right One Junction Box for Your Electrical Needs

재료

The selection of the material for the junction box requires a detailed consideration of your usage environment. You need to consider whether the environment is corrosive and your requirements and costs for the mechanical strength, fire resistance and electromagnetic shielding of the materials.

Overall, you can choose plastic junction boxes for application in dry indoor environments or those free from mechanical shock. For environments with high humidity or containing corrosive gases, you can also choose plastic junction boxes with excellent corrosion resistance. Metal electrical junction boxes are more suitable for places that require high mechanical strength, fire resistance and electromagnetic shielding.

Your Electrical Needs

You need to comprehensively consider the specifications of the conduits that match the junction box and the current-carrying capacity of the internal connections, which must be compatible with the system. If you need to apply it in high-power or frequently start-stop environments, the heat dissipation property of the metal junction box is a major advantage.

Your Mounting Requirements

Can the junction box be fixed on gypsum board, concrete or metal brackets? Does the junction box need to be inspected and maintained frequently? You need to figure out these issues.

In summary, flush-mounted junction boxes are suitable for new construction or decoration projects as they are more aesthetically pleasing. On the contrary, surface-mounted junction boxes are more convenient for maintenance and are suitable for the renovation of buildings. If you apply it to ceiling fans or lamps, you must purchase products with a fan rating indication.

Your Wire Capacity

Regarding wire capacity, you need to consider the number of your wires, their diameters, and the volume of the connectors. Based on these data, accurately assess the size of the junction box you need. A too small junction box may cause overheating and even lead to dangerous situations. You should try to choose a junction box with reasonable wiring and sufficient margin to guarantee proper heat dissipation.

Check Compliance and IP Rating

You must choose the certification mark with the local region. If in an explosive environment, you must choose a junction box with explosion-proof certification, such as ATEX,IECEx or UL 인증.

Which IP rating of jbox to choose depends on your waterproof and dustproof requirements, and this is determined by the environmental humidity, dust, and whether it is in direct contact with water. IP20 is usually sufficient for use in dry rooms. If you apply it in a humid environment, you can choose anIP44 or higher grade. If you apply it outdoors, you should choose a junction box of at least IP65 grade.

자주 묻는 질문

Can indoor junction boxes be used outdoors?

Absolutely not. Indoor junction boxes usually do not have the functions of waterproof, dustproof and UV-resistant. Using indoor wiring appliances outdoors will accelerate aging and water ingress, and may cause short circuits or fires.

How do you match the on-site environment with the protection rating?

You need to precisely assess whether the application requires water resistance, dust resistance, or both. If it is a common indoor dampness, IP44 can be chosen. If it is applied to regular outdoor areas, such as the exterior walls of buildings, you can choose IP65. If it is a more demanding environment, you can choose IP68 or above.

When the environmental conditions are uncertain or may deteriorate, you can choose a higher level of IP rating.

PVC junction boxes or metal junction boxes, which is better?

Which material to choose depends on your application scenario. PVC is suitable for indoor environments. It features insulation, corrosion resistance and low cost. Metals are suitable for industrial environments, outdoors and places with special application requirements. It is more expensive, but stronger and more fireproof.

Final Thought

KDM, a supplier of electrical enclosure with over ten years of experience. Enclosures are produced using robust and durable raw materials to guarantee the quality of your customized enclosure. Our factory also meets ISO 90001,IP66 testing report and UL certification. No matter what kind of junction box you want to customize,KDM can provide you with a comprehensive customized design within 1-3 days. 문의하기 now!