Introduction of smc cable branch box

Introduction of smc cable branch box

Definition ：

Smc cable branch box is the central component for connecting cables and other electrical equipment in distribution lines. Its connection combination method is simple, convenient and flexible. It has the functions of full insulation, full enclosure, corrosion prevention, protection-free, safety and reliability. It is widely used in commercial centers, industrial parks, urban residential areas and a large number of urban power grid renovation projects.

Function：

With the development of the cabling process of the distribution network, when the independent load distribution with small capacity is relatively concentrated, smc cable branch box can be used to connect multiple branches of cables. Since the branch box cannot directly operate each road and is only used as a cable branch, the primary function of smc cable branch box is to tap or transfer cables.

1. Cable tap function:

There are multiple small-area cables on a relatively long-distance line, which often causes the use of cables to be wasted. Therefore, the cables sent to the power load center often use large cables. The large cables are divided into several small-area cables through the smc cable branch box, and the small-area cables are sent to the load point. Such a connection method is widely used in the urban power grid residential area power supply, small users and other power supply.

2. Cable transfer function

On a relatively long line, the length of the cable produced by the manufacturer cannot meet the requirements of the line, so it is necessary to use the cable center connector or the cable transfer box. Generally, the cable center joint is selected for short distance, but when the line is relatively long, according to the experience on the cable line above 1000M, if the cable has multiple center joints, the safe work of the cable will be affected, so the smc cable branch box is considered for transfer and extension.

Structure ：

Commonly used smc cable branch box is divided into American smc cable branch box and European smc cable branch box.

1. American smc cable branch box:

It is the 1 kind of cable engineering equipment widely used in the North American regional power distribution network system, which is characterized by one-way door opening and horizontal multi-pass busbar, and has significant benefits such as small width, combination of active network, full insulation and full sealing. According to the rated current, it can be divided into 600A main circuit and 200A branch circuit. The 600A main circuit adopts screw-in bolt for fixed connection; the 200A branch circuit adopts plug-in connection and can be plugged and unplugged with load.

The cable head selected in the American smc cable branch box is:

T-type cable head; T-II type cable head; Elbow type cable head, these cable heads are suitable for cross-linked polyethylene insulated cables, during which 200A elbow type cable head is suitable for cables with nominal cross section of 35mm ² ~ 120mm ², 600A cable head is suitable for cables with nominal cross section of 50mm ² ~ 500mm ².

Charge indicator:

The American smc cable branch box charge indicator equipment is on the test hole of the cable head (elbow, T, T-II). The LED lamp flashes to judge whether the cable is charged. When the line is charged, the flash lamp of the charge indicator flashes continuously to prompt the staff that the line is charged. When the line is not charged, the flash lamp of the charged flash device does not flash, indicating that the line is not charged. The equipment can be protected.

The charged indicator is wrapped in a semi-conductive rubber boot, fully insulated, fully sealed, with electrical contact, and can adapt to various climates.

fault indicator

The fault indicator equipment of the American branch box is located at the box-type transformer, outdoor ring network cabinet, smc cable branch box, substation inlet and outlet lines and feeder branches, and the line fault is discriminated by turning over the signs (orange indicates the fault, black indicates the normal working condition), so as to facilitate the operator to find the fault in an active way, reduce the fault power outage time, and ensure the reliability of forward power supply.

The cable fault indicator is made of plastic shell with high strength and excellent weather resistance. It is fully insulated and sealed. It can be brought with electrical contact. It is suitable for various harsh environments. It can be immersed in water and work firmly without task protection. When the fault is cleaned, the fault indicator can be reset automatically.

function and characteristics of american branch box:

① fully insulated, fully sealed structure, no insulation distance, safe and secure to ensure personal safety.

② dust, flood resistance, corrosion resistance, protection-free, can be used outdoors, can also be immersed in water, suitable for any harsh environment.

③ The combination is extremely flexible, with up to eight branches of incoming and outgoing lines, satisfying various wiring requirements.

④ small size, compact structure, simple equipment, convenient operation.

The 200A branch cable connector can be used as a load switch, with load plug, and has the characteristics of barrier switch.

The short circuit fault indicator can be connected, easy to find the cable fault.

⑦ The three-core cable needs to be crossed with a large span, and the construction is difficult.

2. European smc cable branch box:

European smc cable branch box is widely used in power distribution network system in recent years in the cable engineering equipment, its primary feature is two-way door opening, the use of wall casing as a connecting busbar, with small length, cable placement clear, three-core cable reverse placement, no need for large-span cross and other significant benefits. The selected cable joints meet DIN47636 standards. Generally, the rated current 630A bolt fixed connection type cable joint is selected.

The function and characteristics of European smc cable branch box:

① Fully insulated, fully sealed and fully protected.

② The inlet and outlet lines are flexible, generally one inlet and 3 4 branch roads, with a maximum of 8 branches.

③ anti-flood, anti-pollution, anti-condensation, anti-frost, corrosion resistance.

④ small size, compact structure, simple equipment, convenient operation.

⑤ The equipment electrification indicator can be used to remind the operator that the line is electrified.

⑥ Cable type fault indicator can be equipped to facilitate flexible cable fault finding.

Types of smc cable branch box:

4. cable heads that can be contacted with electricity and cannot be contacted with electricity:

The primary difference between charged accessible cable joint and charged non-accessible cable joint: the former silicone rubber cable joint has a semiconductor shielding layer inside and a conductive shielding layer outside, and is grounded through a metal hoop connection to ensure that the external potential of the cable joint is the same as the ground potential; The latter is the same silicone rubber cable joint, and the ground voltage of both is zero after actual measurement results, but in practice, the latter may generate induced static electricity on its external surface, that is, the surface has a floating potential, can cause electric injury.