What are the models of power cables? How is the value of the allowable current calculated?

The model of the cable consists of eight parts:

1. Use** Not marked as a power cable, K is a control cable, and P is a signal cable;

2. Insulation** Z oil-impregnated paper, X rubber, V polyvinyl chloride, YJ cross-linked polyethylene.

3. Conductor material** is not marked as copper, l is aluminum;

Fourth, the inner sheath ** Q lead package, L aluminum package, H rubber sheath, V polyvinyl chloride sheath.

Fifth, derivation** d does not drip flow, p dry insulation;

Sixth, the outer sheath **.

7. Special products** TH wet tropical, TA dry tropical;

8. Rated voltage unit: kv

Second, the naming of wires and cables, the naming of wire and cable products has the following principles:

The full naming of wires and cables is often complicated, so people sometimes use a simple name (usually the name of a category).

Combine the model specification to replace the full name, such as "low-voltage cable" to represent all plastic insulated power cables.

The type spectrum of wires and cables is relatively perfect, so it can be said that as long as the standard model specifications of wires and cables are written, the specific products can be clarified.

First of all, it is necessary to calculate the total power of the electrical equipment;

The current is then calculated from the power, which is the current carrying capacity;

Finally, according to the current carrying capacity, the size of the cable is determined.

For example: a motor with a total power of 50kw, when converted into a current of 100A, that is, the current carrying capacity of 100A, 100A needs at least 25 square cables, considering that some cables are not national standards, so at least a larger cable is used, that is, 35 square meters!

After reading the examples, you will definitely ask, how to convert power into current, and how to determine the cable specification of current. This problem varies depending on the temperature, material, and electrical equipment.

I can say the simplest rough way to memorize, which is that 1kw corresponds to 2A, a square of five amps.

Calculated as a safe current per square ampere, i.e. multiplied by the square number of cable cores.

The current of the cable can be measured by the ammeter, and the current carrying capacity of the cable can be directly referenced by looking up the meter, and there is no need to calculate it effortlessly.

The long-term safe current carrying capacity of different types of cables is also different, and it can be found in the electrician's manual (or online) without calculation.

The specifications are mainly 1 square, square, square, etc.; It is determined according to three factors: wire material and wire cross-sectional area, and wire laying conditions.

In electric power engineering, the current carrying capacity of the conductor is determined by three factors: the conductor material, the conductor cross-sectional area, and the conductor laying conditions. A single wire can take a higher current carrying capacity than multiple parallel wires; The open wire laying wire can take a higher current carrying capacity than the wire laid through the pipe; Copper conductors can have a higher ampacarrying capacity than aluminum conductors.

The wire load current value specified in the Chinese national standard GB T requires that the allowable long-term load current of 1 square copper core wire is 8A-12A; The square copper core wire allows the long-term load current to be 12A-15A; The square copper core wire allows the long-term load current to be 16A-25A; The allowable long-term load current of 4 square copper core wire is 25A-32A; The allowable long-term load current of 6 square copper core wire is 32A-40A.

The list of cable specifications and models is as follows:

1. Specifications and models of VV, VLV, VV22 and VLV22 cables.

2. YJV, YJV22, YJV32, YJV42, YJV43, YJLV, YJLV22, YJLV32 and other cable specifications and models.

3. BV, BLV, BVR, BVVB, BVV cable specifications and models.

4. RV, RVB, RVS, RVV, RVVB cable specifications and models.

5. Specifications and models of RVP and RVVP cables.

6. NH-VV, NH-VV22 cable specifications and models.

Various cable functions.

1. SYV: solid polyethylene insulated RF coaxial cable, coaxial cable, wireless communication calling, broadcasting, monitoring system engineering and related electronic equipment transmission of radio frequency signals (including comprehensive coaxial cable).

2. SYWV (Y): Physical foamed polyethylene insulated cable TV system cable, video attitude frequency (RF) coaxial cable (SYV, SYWV, SYFV) are suitable for closed-circuit monitoring and cable TV projects. SYWV (Y), SYKV cable TV, broadband network special cable structure:

Coaxial cable) single oxygen-free round copper wire + physical foamed polyethylene (insulation) + (tin wire + aluminum) + polyvinyl chloride (polyethylene). 3. Signal control cables (RVV sheathed wire, RVVP shielded wire) are suitable for building intercom, anti-theft alarm, fire protection, automatic meter reading and other projects. The above content reference:

Encyclopedia - cable <>

Let's go and see it here, it's clear.

Copper core wire 6a mm².

Aluminum core wire 4a mm².

Single-core branch cable specification notation: the number of cables in the same loop * (1 * nominal cross-section), such as: 4 * (1 * 185) + 1 * 95

Specification notation of multi-core stranded branch cable: the number of cables in the same loop * nominal cross-section, such as: 4**185+1*95

Specification notation of multi-core and sheathed branch cables: the number of cable cores Nominal cross-section-t, such as: 4 25-t