When mounting electrical wiring or electronic communications, it is necessary to make nodal points at which there are transitions from one bus to another or branching from the main line in the directions going to specific objects or electrical devices. Such places must first of all be safe and reliably protect the connected contacts from environmental influences. For these purposes, developed junction boxes.
What are junction boxes
A plastic junction box (or metal) is a box of round, square or rectangular shape, equipped with holes for the entry of electrical cables. The main objective of the product is to provide protection for the wiring of wires, which can be interconnected internally by soldering, twisting or using terminal blocks. The received bends are forwarded in any direction.
The junction boxes of the outdoor installation belong to the group of electrical equipment. Their specificity implies the presence in these devices of elements responsible for the tightness of the connections inside. So, they are equipped with gaskets, couplings, which prevent moisture from entering the housing through the inlets and the cover.
Application area
The area where you can use the junction boxes, concerns the supply of electricity and electrical signals that are transmitted using wires. Therefore, several of their types are distinguished:
- Conventional electrical distribution - designed for the implementation of the wiring of the supply voltage in domestic and industrial conditions. Such boxes can also be used for direct current.
- Telephone, computer, for wiring alarms - multicore buses are bred into them. They are usually equipped with terminals and a protective system against penetration.
- Outdoor junction boxes for high-frequency and ultra-high-frequency (microwave) equipment. In them, not only the wiring of the wires is possible, but the installation of small circuits is permissible. The case must be shielded, and the contents are sometimes filled with a waterproof compound if the equipment is operated under conditions of high humidity.
Classification of electrical wiring boxes
Outdoor junction boxes are divided according to several criteria.
Production Material:
- Polymer - polyethylene, polypropylene, polystyrene cases.
- Metal - from tin or aluminum and its alloys.
Appointment:
- Household - for breeding electrical wiring, where single-phase networks are used.
- Industrial - mini-boxes of increased strength, where three-phase voltage wires are bred.
- Special - outdoor junction boxes for breeding signal cables for pulsed, radio frequency and microwave equipment.
Installation method:
- Open type - wiring passes outside the surface.
- Hidden type - the cable is hidden inside the strobes.
Security Level:
- IP44 - boxes that are allowed to be used outdoors under cover from direct rain, dust, in rooms with a humid environment.
- IP55 - boxes that withstand short-term direct ingress of water and do not allow dust. The most popular form of distribution equipment.
- IP65 - designed for installation in places highly exposed to the atmosphere, do not allow rainwater and dust.
- IP67 - can be continuously located in a humid environment, for example, underground or on its surface.
- IP68 - able to protect the wiring under water. They are designed for shallow depths.
Junction box designs
All junction boxes for electrical wiring have the basic typical structural elements, but there are some differences in the details.
Surface mount boxes include:
- Square, rectangular or round box with holes for wiring on the sides, threaded bushings for the inlet of the screws of the cover, bushes for mounting the DIN rail and holes for mounting to the bearing surface.
- A cover equipped with a channel for sealing gum and holes for screws attaching to the box. The technical parameters of the product are usually indicated on its outer surface.
- Cable entry glands or wires.
- Four screws securing the cover.
- Sealing gum.
- DIN rail for connecting wires (not available on all models).
- A security button that is connected to the alarm to prevent unauthorized access (only available on special-purpose models).
Boxes of an external installation of a mortise type differ from those described above in that there are no sealing gum and oil seals, since the entire surface is hidden under a layer of putty, which, being moisture resistant, itself provides tight protection.
In metal boxes, cable channels are inserted through threaded fittings. They more reliably protect compounds from weathering. Such products do not need to be shielded.
Connection box connection
To install the wiring box, you need such an installation tool:
- Electric drill with shock function.
- Pliers.
- Screwdriver for flat and curly slot.
- Assembly knife with interchangeable blades.
Additional items:
- Roll of electrical tape.
- The clamping terminals are electric.
- Fixing material (screws, plastic dowels).
The installation procedure for the outdoor junction box for electrical wiring is as follows:
- At the installation site, holes are drilled for attaching the box to the plane, the dowels are clogged.
- In glands with a knife, cut holes for the desired wire diameter.
- Inside, screw the electrical terminals to the desired number of contacts.
- The box is attached to the wall with screws, screwing them into the dowels.
- Through the obtained holes in the seals, wires are introduced.
- Strip the ends of the wires from the insulating material and remove the oxidation layer, if any.
- Assemble the circuit in the junction box, securing the wires in the corresponding terminals.
- Close the box lid, fixing it with threaded screws.
Benefits of using junction boxes
Ease of use of mounting boxes is quite reasonable:
- Products are produced under different power lines.
- A high degree of contact protection is provided with the right type of device.
- Lack of complexity of mounting the housing and connecting wires.
- A wide selection of shapes and decorative designs, for example, junction boxes for outdoor wood installation.
- Ability to access communications and reconnect.
- Durability of construction.
Conclusion
Despite the simplicity of the installation of junction boxes, it is important to remember that only electricians and electronic engineers have access to this kind of activity when it comes to wiring signal wires!