Power cables are insulated wires that are enclosed in one or more protective sheaths. Its purpose is to ensure the reliability and safety of electrical wiring in production and in everyday life. There are a number of factors to consider when choosing the right power cable from a wide range of products.
Instructions
Step 1
Select your power cable based on the conductor material, which can be copper or aluminum. Copper has good conductivity and is less susceptible to corrosion. From a fire safety point of view, copper cable is also preferable.
Step 2
Calculate the total power of the load on the cable. To do this, you need to determine the power of all consumers at the connected object, using the information specified in the technical documentation of these devices.
Step 3
Calculate the cross-sectional area of the wire (core) of the power cable based on the calculated load power and current strength. It's easy to do it using special tables. Keep in mind that at low amperage values, the cross-section of the copper conductor must be at least 1 mm², and the aluminum one - 2 mm².
Step 4
To choose the right power cable, you need to navigate in the marking of its various types. So, the first letter in it denotes the material of the conductor (for example, "A" - aluminum cable). In the marking of the copper cable, the letter is not put down.
Step 5
Identify the insulation material by the second letter in the power cable marking. It can be made of rubber (denoted by the letter "P"), polyvinyl chloride (denoted by "B"), polyethylene - "P". If the cable is intended for laying in pipes, the letter "T" is present in the marking, and "G" means that the cable is flexible.
Step 6
Select the cable with the required insulation depending on the installation conditions. So, if it is necessary to mount the wiring in a vertical position, it is recommended to use PVC insulation (for example, AVVG and VVG). For laying in high humidity conditions, a wire with a special protective cover and a lead sheath is required.
Step 7
Determine the voltage in your network (220 or 380 V) and the number of phases used. Depending on this, select the power cable according to the number of conductors in it. So, for a voltage of 220 V and one phase, two or three cores are needed, for a voltage of 380 V and three phases - three or four. The number of conductors and their cross-sectional area must be marked in the marking. So, for example, the numbers 3x1, 5 mean that the cable is three-core, with a cross-section of each conductor of 1.5 mm².
Step 8
Calculate the required cable length. To do this, you need to know the distance from the point of connection of the object to the place of installation of consumers. Calculate the amount of cable required to "cut" it, that is, release from insulation for connection, at the rate of 1 meter per 1 consumer. Add to the resulting figure 8% for bends, since the power wiring must be laid without tension. In any case, it is better to buy a cable with a margin, so as not to build it up later.
