Q&A about Cable and Wire

1. What are the requirements for fixing AC single-core cables? why?
The clamp should have no iron to form a closed magnetic circuit. This is because when the cable core passes current, magnetic lines of force are generated around it. The magnetic line of force is proportional to the current through the core. If iron and other magnetic materials are used, Electromagnetic induction knows that eddy current will be generated in the iron to make the cable heat up and even burn the cable. Therefore, iron pieces cannot be used as fixing fixtures for single-core AC cables.

2. What are the biggest features and advantages of the following heat shrinkable cable head accessories?
The biggest feature of heat shrinkable accessories is the use of stress tubes instead of traditional stress cones. It not only simplifies the construction process, but also reduces the size of the joint terminal, which is convenient to install, save time and labor, has superior performance and saves metal. The heat-shrinkable cable accessory integrates the perfusion type and the dry pack type into one, which combines the advantages of these two accessories.

3. What inspection work should be carried out before cable laying?
(1) The bracket should be complete and paint complete.
(2) The cable type, voltage, and specifications conform to the design.
(3) The cable insulation is good. When there is doubt about the sealing of the oil-paper cable, the damp judgment should be made; the direct-buried underground cable and the small bottom cable should pass the DC withstand voltage test; the oil sample of the oil-filled cable should pass the test.
(4) The oil pressure of the oil-filled cable should not be lower than 1.47MPa.

4. what does AAAC stand for?
AAAC means Aluminum Alloy Conductor ,is a concentric-lay-stranded conductor consisting of aluminum-alloy wires available in both single layer and multi-layer constructions.
All Aluminum-Alloy Conductors (AAAC) can be used in Medium, High and Extra-High voltage transmission lines. AAAC offers better sag performance due to the high strength-to-weight ratio provided by the aluminum-alloy. In addition, AAAC provides a higher corrosion resistance than ACSR conductors.

5.What is Quad Moose conductor?
Moose is one specification of ACSR conductor ,under British Standard EN50182 (BS215), which structured by 54 strands aluminum wire and 7 strands steel wire, single diameter of each wire is about 3.53mm.

6. What are the advantages of cross-linked heat shrinkable cable accessories?
Answer: This is a new type of material. Compared with other types of accessories, it has the advantages of superior electrical performance, small size, small quality, easy installation, and matching materials. In addition, it has weather resistance, pollution resistance, flame retardant self-extinguishing, etc. ability.

7. When there are doubts about the sealing of oil-paper insulated power cables, how to check whether the cable insulation paper is damp in a simpler way?
Answer: Ignite the cable insulation paper or put it in the cable oil at about 150℃ to check, there is no “hissing” or white foam, indicating that it is not damp.

8. What should be indicated on the cable sign? What are the requirements for writing?
Answer: The cable circuit design number, cable model, specification and starting point should be indicated on the sign, and the cables used in parallel should have a sequence number. The handwriting is required to be clear and not easy to fall off.

9. Where should the azimuth signs of directly buried cables be set?
Answer: At both ends of the cable, the cable connector is at 50~100m of the straight section of the cable and the corner where the cable changes direction.

10. How to make the yellow wax ribbon, black glass lacquer tape, alkali-free glass ribbon, etc. used to make cable joints before construction?
(1) Constant temperature drying method: roll the insulating tape into a small roll with a diameter of 25~30mm, put it in a 110~120℃ constant temperature drying oven for 4~5h, cool and dry it out, and put it into a dry sealed cylinder.
(2) Oil immersion and moisture removal method: Put the small coil of insulation tape into the cable oil at a constant temperature of 120~130℃, keep a distance of 30mm from the bottom of the pot, after a certain period of time, the oil surface will no longer produce foam, then take it out and put it into storage In the barrel with cable oil, the oil level should exceed all the contents and seal it.

What’s The Difference Between ACSR and AAAC cable ?

Following are some Q&A people interested about wire and cables :

1. What types of commonly used wires and cables are classified by purpose?
Answer: According to the purpose, it can be divided into bare conductors , insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, radio frequency cables, etc.

2.What is the difference between ACSR cable and AAAC cable ?
AAAC:This bare concentric-lay-stranded conductor, made from round aluminum alloy 6201 -T81 wires, is constructed with a central core surrounded by one or more layers of helically laid wires.
it provide better corrosion resistance than the one produced by the aluminum conductor steel reinforced(ACSR).
ACSR: This bare concentric-lay-stranded conductor is made from round aluminum 1350-H19 (extra hard) wires and round zinc-coated or aluminum-coated steel core wire(s) to be used as overhead electrical conductors.it provides better strength than AAAC cable.

3. What kinds of insulated wires are there?
Answer: There are the following types of insulated wires: PVC insulated wires, PVC insulated cords, nitrile and polyvinyl chloride compound insulated cords, rubber insulated wires, direct buried aluminum core plastic insulated wires for agricultural use, and rubber insulated cotton yarn Textile cords, PVC insulated nylon sheathed wires, PVC insulated cords for power and lighting, etc.

4. What kind of occasion is the cable tray suitable for?
Answer: The cable tray is suitable for the overhead laying of power cables and control cables indoors and outdoors in general industrial and mining enterprises, and can also be used for indoor and outdoor installations in telecommunications, radio and television departments.

5. What are the cable accessories?
Answer: Commonly used electrical accessories include cable terminal junction box, cable intermediate junction box, connecting pipe and terminal block, steel plate junction box, cable tray, etc.

6. What is the cable middle connector?
Answer: The device that connects the cable and the cable’s conductor, insulation shielding layer and protective layer to connect the cable line is called the cable intermediate joint.

7. What is electrical main wiring?
Answer: The electrical main wiring is the connection method of the main electrical equipment and the bus in power plants and substations, including the connection of the main bus and the auxiliary power system according to certain functional requirements.

8.When choosing the cross section of the power cable, which regulations should be followed?
Answer: The selection of power cables should follow the following principles:
(1) The rated voltage of the cable should be greater than or equal to the rated voltage of the power supply system at the installation point;
(2) The continuous allowable current of the cable should be equal to or greater than the maximum continuous current of the power supply load;
(3) The cross-section of the core must meet the requirements of stability of the power supply system when it is short-circuited;
(4) Check whether the voltage drop meets the requirements according to the cable length;
(5) The minimum short-circuit current at the end of the line should enable the protection device to operate reliably.

9. What are the advantages of XLPE cables and oil-paper cables?
Answer: (1) Easy to install, because it allows a small minimum bending radius and light weight;
(2) Not restricted by line drop;
(3) Good thermal performance, high allowable working temperature and large transmission capacity;
(4) The cable accessories are simple and all are dry structure;
(5) Simple operation and maintenance, no oil leakage problem;
(6) The price is lower;
(7) High reliability and low failure rate;
(8) There are few manufacturing procedures, simple process and remarkable economic benefits.