Why don t high voltage cables be made into a regular triangle with a cross section, so that the wate

Personally, I think there are 2 points.

1.Make a regular triangle, the installation is inconvenient and the loss is greater, after all, the installation is people, the three-edged wire is too worn out on the gloves, and the loss here is the life loss of the wire caused by thermal expansion and cold contraction.

2.Making a regular triangle doesn't solve the problem you're talking about. There are two ways in which icing occurs:

One is snowfall, where snow covers the power lines, then the temperature drops, and the snow turns into ice on the power lines, and the second is rain (freezing rain), and as soon as the contact point line immediately turns into ice. Either way, icing, making a regular triangle won't solve the problem. Of course, you can say that if the rain falls on the power lines and then the temperature drops, it will also freeze.

This assumption is good, but on the metal surface (most of the current outdoor wires are aluminum alloys) can not stay much water, and the effect is not much different when made into different shapes. And it's not what you might think, in fact cylindrical wires make it easier for water to run down.

Low-voltage cables can be made into triangles, but high-voltage cables can't be made for two reasons:

1.High-voltage cables are generally made of polyethylene as the main insulating material, and the characteristics of this material are not suitable for making triangles, and the triangles will be damaged when laid unevenly. If it is made into a circle, the allowable deformation range is much larger.

2.The shape of the electric field determines the shape of the cable, the electric field is circular, and the cable and the insulating layer are made circular to be more uniform in-situ stress.

The cable is a multi-strand thin wire, which is twisted into a thick wire, how can it be twisted into a triangle? It's up to you to research and develop. Solving this world's problem.

The biggest disadvantage of making a triangle is that it is not easy to bend and difficult to lay.

The regulations that should be complied with are as follows: (1): The number of pipe holes should be reserved for appropriate standby development.

2): Cables with large differences in the working temperature of the cable core should be configured in different pipe groups with appropriate spacing. （3）：

The thickness of the soil cover at the top of the pipe section should not be less than (4): The pipe should be placed on a pad that has leveled the compacted soil layer and has enough to maintain continuous straightness.

Copper square 6a

Aluminum square 5a

The square of the wire x 6 or 5 = maximum current, load power divided by voltage = current (resistive load) e.g. light bulb load power x2 = current (inductive load limiting) e.g. motor.

The wire table is: cross-section, you can understand the thickness of the wire, the cross-sectional area is large, the current that can pass is large, and the load power is large.

Copper core wire: The cross-sectional area of copper core wire allows for long-term current.

square millimeters (16a, 25a).

4 mm² (25a, 32a).

6 mm² (32a, 40a).

Aluminum core wire: The cross-sectional area of the aluminum core wire allows long-term current.

square millimeters (13a, 20a).

4 mm² (20a, 25a).

6 mm² (25a 32a).

Joule's law.

Proportional relationship. The larger the conductor cross-section, the greater the current carrying capacity.

Check the table The current carrying capacity of the cable is related to the cable cross-section, the number of roots, the service life and so on.

It should be the relationship with the current, calculate the current according to the load, and then select the cable according to the current.

How to calculate the square of wires, and what is the comparison table of wire squares and power.

Current A = power p voltage U, calculate the current A can be selected according to the current, the copper core wire is calculated by 4-7A square millimeters, the aluminum core wire is calculated by square millimeters, the larger the wire diameter, the smaller the current density.

Power cannot be directly converted to wire squared! To know the voltage value, the power is divided by the voltage to get the current value, and it is easy to find the square according to the current magnitude and the current-carrying density of the cable. For example, (single-phase) 220V, 5000W, the current is approximately 23A, and the current carrying density of the overhead bare wire is 6A mm2, which can be taken 4 squares; The current-carrying density of the insulated wire is 3a mm2, so it is necessary to take 8 squares.

Because the current transformer shall not be opened, 5A, in order to avoid external force breaking, it is stipulated that a square line should be used.

If it is a multi-core cable, the distance is not long, and the square is enough.

The small triangle represents the disconnector, the triangle below indicates the cable head, and the branch circuit is a disconnector with a varistor underneath, and the resistance is grounded. There should also be a circuit breaker (which should be a vacuum switch) and a current transformer on top of the main circuit.

Like a normal switch, it is a push-button type, and the travel switch automatically resets when the device does not touch it. The disconnect point in the main circuit represents the disconnector, the triangle below represents the cable head, and the branch circuit is an isisolating switch with a varistor under it, and the resistance is grounded.

1. Respect the teacher, when you are in school, what is working silently;

2. Generally speaking, the "small triangle with the arrow pointing down" is the sign of the cable head, you can check the "graphic symbols for electrical diagrams", which has a national standard; The cable terminal is represented by a triangle, and the arrow points to the other end of the cable, which is the correct way to draw; Your incoming high-voltage cabinet is the next incoming line, of course, the arrow is pointing downward;

3. Many units understand the arrow as a sign of the power supply, and mistakenly think that the power supply is from the bottom up, then the arrow should be up, which is wrong.

National Standard Wire Acceptance Criteria:

1. First of all, there should be CCC certification "CCC" and "factory number" marks on the wire body, and there are two signs on the wire body to indicate that the wire manufacturer has passed the national compulsory certification.

2. The conductor resistance is qualified.

3. There are no visible pores on the insulation and sheath sections, and the color is pure and the appearance is smooth.

4. The distance between signs.

Cables: Cables are usually rope-like cables made up of several or groups of wires (at least two in each group), each of which is insulated from each other and often twisted around a center, with a highly insulating covering on the entire outskirt. Most of them are erected in the air or installed underground or underwater, and are used for telecommunications or power transmission.

In 1832, the Russian veteran officer Schullinger buried the telegraph line in the ground, and the six wires were insulated with rubber from each other and placed in glass tubes, which was the world's first underground cable.

It depends on what cable you are.

Cables: rvv, vv, high voltage. These are not the same, have they been tested by the Technical Supervision Bureau?

If there is, look at the inspection report. Just get it.

Wire and cable testing items are targeted according to different product series, such as: 1. Series: RV, RVV, BV, BVR, YJV, etc.;

2. Model: 02RV 06RV 52RVV 74RVVYP 75RVVY BV01

3. Conventional testing items: product specifications, size, high-voltage test, conduction test, insulation thickness, conductor resistance.

If you need detailed information, you can look at the printing on your product to know what series of products and what standards are used. Bonus points.

1,5 and 2,5 are nine times, 4 square is eight times, and 6 square is seven times. It is the square of the wire multiplied by the multiple is the rated current of the wire, which is the safe current carrying capacity below 25 degrees, so there must be a certain amount of abundance when choosing the wire, and then you divide the power of the equipment by the voltage is the current of the electrical equipment.

First calculate the current, if it is an electric heating appliance such as (infrared heater, etc.), use 3000w 220v =, and then check the conductor interception section of the electrician's manual, and select the appropriate wire cross-section, such as the square copper core wire at an ambient temperature of 40 degrees, the interception rate is 15a, of course, you can also choose a larger wire. For example, the square line cut-off is 19a.

Simple estimate: the wire can withstand a maximum of 5A per square millimeter; Power is equal to current multiplied by voltage. So you can roughly deduce it