Electrical power | power cables | wires with copper conductors

Choosing the right power cable is a crucial step in ensuring the safety, efficiency, and longevity of electrical installations.

An improper choice of cable can lead to various problems, including overheating, fire risks, and damage to equipment.

Below are important aspects to consider when selecting a power cable, along with common mistakes.

Cable Selection Rules:
Cable Cross-Section (Current Carrying Capacity):

The main factor in choosing a cable is its cross-section, which must match the expected current load. If a cable with too small a cross-section is selected, it can overheat and damage the installation.

For example, a 1.5 mm² cable is commonly used for lighting, while a 2.5 mm² cable is used for electrical outlets.
Formula: To calculate the required cable cross-section, you need to know the load power (in watts) and voltage (in volts).

The current can be calculated using the formula: Current (A) = Power (W) / Voltage (V).

Length and Voltage Drop:

The length of the cable significantly affects power supply. The longer the cable, the greater the voltage drop, which can lead to reduced equipment efficiency or improper operation.
It is recommended that the voltage drop should not exceed 3-5% of the nominal voltage. If the cable is long, a larger cross-section cable should be selected.

Material (Copper or Aluminum):

Copper is the most commonly used material due to its excellent conductivity properties, but it is more expensive. Aluminum is used when a more economical solution is needed, but aluminum conductors must be thicker than copper ones due to their higher resistance.
Copper cables are generally more durable, better withstand high currents, and are more resistant to corrosion.

Type of Insulation:

The cable insulation must match the conditions of use. If the cable will be laid outdoors or in damp areas, a cable with UV and moisture protection should be selected (e.g., CYKY-J). For indoor installations, where extreme conditions are not present, PVC insulation is suitable.
It is also important to ensure that the insulation is appropriate for the temperature at which the cable will be used.

Environment (Indoor or Outdoor Installation):

If the cable will be used outdoors, consider the effects of UV radiation, moisture, and temperature fluctuations. If the cable will be laid underground, specially designed cables with stronger protection against mechanical damage and moisture must be used.

Protective Measures:

It is necessary to protect the cable from mechanical damage, especially where it is run through walls or floors. It is also important to ensure that the circuit protection devices, such as automatic circuit breakers or fuses, are properly installed to protect the cable from overloads or short circuits.

Common Mistakes in Selecting Power Cables:
Incorrectly Selected Cable Cross-Section:

One of the most common mistakes is incorrectly selecting the cable cross-section according to the load. If the cross-section is too small, the cable can overheat and pose a fire hazard. If it is too large, it can be an expensive and unnecessary solution, increasing the project's cost.
Users sometimes overlook that certain equipment (e.g., motors) can cause a high starting current, which may be several times greater than the nominal current.

Ignoring Voltage Drop:

In long cables, ignoring the voltage drop can reduce the efficiency of the final device, increase energy losses, and cause certain equipment to malfunction.

Incorrectly Selected Insulation:

A common mistake is using inappropriate cables in certain environments, such as using indoor cables outdoors or in damp areas where greater protection against environmental factors is required.
Failure to use suitable insulation in extreme conditions can lead to faster wear or failure of the cables than expected.

Ignoring Installation Environment:

Laying cables in aggressive environments, such as areas with mechanical impact or chemical substances, without proper protection can lead to cable failure. In underground installations, it is essential to use properly protected cables or special conduits.

Insufficient Protection Against Overloads and Short Circuits:

Failure to install appropriate protective measures, such as automatic circuit breakers or fuses, can be dangerous, as cables may be damaged due to overloads or short circuits.
It is also important to consider the expected load and power fluctuations so that protective measures are adequately tailored.

Overvaluing Costs:

Some people choose cheaper cables that may be of insufficient quality or unsuitable for specific conditions. This can lead to higher long-term costs due to potential issues and the need for repairs.

Ignoring National and International Standards:

Ignoring or not adhering to electrical installation standards (e.g., IEC or local electrical installation regulations) can lead to serious mistakes that may pose safety risks and require reinstallation.

Conclusion:
Choosing the right power cable depends on the current load, cable length, environmental conditions, and materials used. The most common mistakes include incorrect selection of cable cross-section, ignoring voltage drop, environmental impact, and neglecting protective measures. A properly selected cable ensures safety, efficiency, and longevity in electrical installations.
Cables with copper conductors are an excellent choice due to their efficiency, durability, and reliability, ensuring a reliable power supply in various fields. Many people wonder what type of service entrance cable to use for a private house—copper or aluminum? Both copper and aluminum power cables are suitable for electricity supply. Almost all underground electrical networks use aluminum power cables. Compared to copper power cables, especially larger diameter aluminum power cables (AXMK) are significantly cheaper. It is recommended to lay the service entrance cable in a corrugated pipe and additionally use a protective tape that further protects the cable from mechanical damage. Above the protective tape, a warning tape stating "cable" should be laid 10-15 cm. Using a gel lubricant or a puller can facilitate the introduction of cables into the main devices.