Complete Guide to Electrical Cables: Types, Selection, and Best Installation Practices
Learn about the different types of electrical cables, the criteria for their selection, and the best practices for safe and long-lasting installation. Includes information on insulation, standardized colors, sizing, and essential technical standards.
11 August 2025
I. FUNDAMENTALS AND CONCEPTS
1. What is the technical distinction between a wire and a cable?
The main distinction lies in their composition. A wire is a single, solid, and rigid conductor. A cable consists of several finer wires twisted together, which provides greater flexibility. Both have the same current-carrying capacity for the same nominal cross-section, but the cable is preferable in installations that require more flexibility or vibration resistance.
2. What does the "nominal cross-section" of a cable mean (e.g., 1.5mm², 2.5mm²)?
The nominal cross-section, measured in square millimeters (mm²), refers to the area of the conductor’s cross-section. It is the main characteristic that determines the cable’s capacity to carry electrical current. Cables with a larger nominal cross-section can carry more current without overheating, making them essential for higher-power equipment.
3. What are the standardized colors of conductors and their meaning?
Standardization is crucial for the safety of electrical installations. Colors follow the European standard:
1. What is the technical distinction between a wire and a cable?
The main distinction lies in their composition. A wire is a single, solid, and rigid conductor. A cable consists of several finer wires twisted together, which provides greater flexibility. Both have the same current-carrying capacity for the same nominal cross-section, but the cable is preferable in installations that require more flexibility or vibration resistance.
2. What does the "nominal cross-section" of a cable mean (e.g., 1.5mm², 2.5mm²)?
The nominal cross-section, measured in square millimeters (mm²), refers to the area of the conductor’s cross-section. It is the main characteristic that determines the cable’s capacity to carry electrical current. Cables with a larger nominal cross-section can carry more current without overheating, making them essential for higher-power equipment.
3. What are the standardized colors of conductors and their meaning?
Standardization is crucial for the safety of electrical installations. Colors follow the European standard:
- Green/Yellow: Protective conductor (Earth)
- Blue: Neutral conductor
- Brown, Black, or Gray: Phase conductor
II. CABLE SELECTION
1. What criteria should be considered when choosing the ideal cable for an electrical installation?
a. Load Power
The power of the equipment to be powered determines the electrical current the cable must carry. The higher the power, the larger the cable cross-section should be.
b. Type of Load
Resistive loads (such as heaters) and inductive loads (such as motors) behave differently. Inductive loads require special attention to inrush current and voltage drop.
c. Installation Distance
The longer the distance between the power source and the point of consumption, the greater the voltage drop. This may require using cables with a larger cross-section to compensate for the loss.
d. Installation Environment (Indoor/Outdoor)
Outdoor installations require cables with protection against UV rays, temperature variations, and humidity. Indoor environments may allow simpler insulation, depending on conditions.
e. Type of Insulation
The cable must comply with standards such as NP EN 50525, IEC 60228, and CPR (Construction Products Regulation), ensuring fire safety and proper electrical performance.
g. Installation Conditions
2. How to determine the appropriate cable cross-section for your project?
The choice of cross-section depends on three crucial factors:
3. Which type of insulation is most suitable for each application?
The insulation type should match the application and environment:
4. Are Nortécnica cables suitable for outdoor applications?
Yes, our cable range includes products specifically designed with materials resistant to UV rays and extreme temperature variations. Check each product’s specifications or contact our technical team to ensure the ideal choice.
1. What criteria should be considered when choosing the ideal cable for an electrical installation?
a. Load Power
The power of the equipment to be powered determines the electrical current the cable must carry. The higher the power, the larger the cable cross-section should be.
b. Type of Load
Resistive loads (such as heaters) and inductive loads (such as motors) behave differently. Inductive loads require special attention to inrush current and voltage drop.
c. Installation Distance
The longer the distance between the power source and the point of consumption, the greater the voltage drop. This may require using cables with a larger cross-section to compensate for the loss.
d. Installation Environment (Indoor/Outdoor)
Outdoor installations require cables with protection against UV rays, temperature variations, and humidity. Indoor environments may allow simpler insulation, depending on conditions.
e. Type of Insulation
- PVC: Versatile, economical, ideal for low voltage.
- XLPE: High thermal and chemical resistance, suitable for medium and high voltage.
- Rubber: Excellent flexibility and durability, ideal for industrial environments.
The cable must comply with standards such as NP EN 50525, IEC 60228, and CPR (Construction Products Regulation), ensuring fire safety and proper electrical performance.
g. Installation Conditions
- Ambient temperature
- Ventilation
- Installation method (in tray, embedded, buried, etc.) These factors influence heat dissipation and the cable’s current-carrying capacity.
2. How to determine the appropriate cable cross-section for your project?
The choice of cross-section depends on three crucial factors:
- Load Current: The amount of current the cable must carry.
- Cable Length: Longer cables experience greater voltage drop, which may require increasing the cross-section to compensate.
- Installation Conditions: The environment (e.g., temperature, ventilation) and installation method (e.g., in tray, embedded in wall) influence the cable’s heat dissipation capacity.
3. Which type of insulation is most suitable for each application?
The insulation type should match the application and environment:
- PVC (Polyvinyl Chloride): Most common for low voltage, versatile, and cost-effective.
- XLPE (Cross-linked Polyethylene): Offers higher resistance to heat and chemicals, ideal for medium and high voltage cables.
- Rubber: Used in flexible cables for portable equipment and industrial environments due to durability and mechanical resistance.
4. Are Nortécnica cables suitable for outdoor applications?
Yes, our cable range includes products specifically designed with materials resistant to UV rays and extreme temperature variations. Check each product’s specifications or contact our technical team to ensure the ideal choice.
III. INSTALLATION AND BEST PRACTICES
1. What are the recommended best practices for electrical cable installation?
2. Is it allowed to install signal cables near power cables?
Not recommended for standard cables, as interference may occur. However, it is possible with Nortécnica’s range of special cables.
3. What safety measures should be adopted during cable installation?
Safety is our priority. Always switch off the electrical power before any intervention. Use appropriate personal protective equipment (PPE), such as insulating gloves and safety glasses. Always follow the applicable electrical safety standards and regulations.
4. Is it advisable to use terminals on flexible conductors?
Yes, to ensure a firm connection and to prevent wires from loosening or being damaged over time.
5. What tools are essential for installing electrical terminals?
1. What are the recommended best practices for electrical cable installation?
- Avoid tight bends and mechanical stress
- Use suitable conduits
- Protect against moisture, excessive heat, and electromagnetic interference (EMI)
- Proper stripping: When removing insulation, use a wire stripper to avoid cutting or damaging copper strands
- Terminals and connections: Always use crimp terminals or twist connectors for splices and connections
- Identification: Label cables to indicate their function (phase, neutral, earth)
- Conduits: Use tubes and trays to protect cables from mechanical damage. Ensure trays are not overcrowded; cables need space to dissipate heat
- Keep away from heat sources: Distance cables from ovens, heaters, or hot water pipes to prevent insulation degradation
- Moisture protection: In humid areas, such as bathrooms and kitchens, use cables and junction boxes with proper protection to avoid water infiltration
2. Is it allowed to install signal cables near power cables?
Not recommended for standard cables, as interference may occur. However, it is possible with Nortécnica’s range of special cables.
3. What safety measures should be adopted during cable installation?
Safety is our priority. Always switch off the electrical power before any intervention. Use appropriate personal protective equipment (PPE), such as insulating gloves and safety glasses. Always follow the applicable electrical safety standards and regulations.
4. Is it advisable to use terminals on flexible conductors?
Yes, to ensure a firm connection and to prevent wires from loosening or being damaged over time.
5. What tools are essential for installing electrical terminals?
a. For Pre-insulated Terminals (Ring, Fork, Pin)
These terminals already have a colored plastic sleeve indicating the cable gauge. The ideal tool is a crimping plier for pre-insulated terminals.
Features:
Jaws with colors or markings matching the terminals (red, blue, yellow).
A ratchet mechanism ensuring correct compression force, only releasing once the crimp is complete to prevent weak crimps.
Many models also include a cable cutter and wire stripper.
b. For Ferrule Terminals (Tubular Ends)
These small metal sleeves are widely used to connect flexible wires to breakers and terminal blocks. The correct tool is a crimping plier for tubular terminals.
Features:
Compresses the terminal into a square or hexagonal shape for a secure, gap-free fit
Quality models also include a ratchet for the ideal compression force for each cable size
c. For Large-diameter Cables
For thicker cables, such as those in switchboards or industrial installations, manual pliers are not enough. In these cases, hydraulic or electric crimping tools are used.
Features:
Use hydraulic force to apply the necessary compression for cables of 16mm² or more
Come with interchangeable dies for different terminal sizes
Other useful tools:
These terminals already have a colored plastic sleeve indicating the cable gauge. The ideal tool is a crimping plier for pre-insulated terminals.
Features:
Jaws with colors or markings matching the terminals (red, blue, yellow).
A ratchet mechanism ensuring correct compression force, only releasing once the crimp is complete to prevent weak crimps.
Many models also include a cable cutter and wire stripper.
b. For Ferrule Terminals (Tubular Ends)
These small metal sleeves are widely used to connect flexible wires to breakers and terminal blocks. The correct tool is a crimping plier for tubular terminals.
Features:
Compresses the terminal into a square or hexagonal shape for a secure, gap-free fit
Quality models also include a ratchet for the ideal compression force for each cable size
c. For Large-diameter Cables
For thicker cables, such as those in switchboards or industrial installations, manual pliers are not enough. In these cases, hydraulic or electric crimping tools are used.
Features:
Use hydraulic force to apply the necessary compression for cables of 16mm² or more
Come with interchangeable dies for different terminal sizes
Other useful tools:
- Wire stripper: For stripping insulation without damaging copper strands
- Cable cutter: For cutting cables to the correct length cleanly and precisely
Using the correct tool for each type of terminal is essential to ensure a safe, firm connection that will not overheat over time.
IV. ESSENTIAL TOOLS FOR ELECTRICAL CABLE INSTALLATION
1. Preparation and Cutting
3. Measurement and Testing
4. Fixing and Organization
1. Preparation and Cutting
- Cable strippers: remove insulation without damaging conductors
- Scissors or cutting pliers: for precise and safe cable cutting
- Electrician’s knife: useful for stripping larger cables or working in tight spaces
- Crimping pliers: for applying terminals to flexible or rigid cables
- Hydraulic crimping tools: used for larger cross-section cables or industrial connections
- MC4 connector tools: essential for solar installations
3. Measurement and Testing
- Multimeters: measure voltage, current, resistance, and continuity
- Cable testers: check connection integrity and polarity
- Non-contact voltage detector: to verify if a cable is live
4. Fixing and Organization
- Cable ties and applicators: for securing cables in trays or on surfaces
- Label makers: for circuit identification and easier maintenance
- Tools for trays and conduits: cutters, benders, and accessory applicators
V. USE AND MAINTENANCE
1. Is periodic maintenance required for electrical cables?
Yes, especially in industrial environments. Visual inspection, continuity testing, and insulation checks are recommended.
2. What signs indicate that a cable is damaged?
Signs include excessive heating, communication failures, voltage loss, or visible damage to the insulation.
3. Can cables be reused in new installations?
Only if they are in good condition and compatible with the requirements of the new installation. Reuse should always be validated by a qualified technician.
1. Is periodic maintenance required for electrical cables?
Yes, especially in industrial environments. Visual inspection, continuity testing, and insulation checks are recommended.
2. What signs indicate that a cable is damaged?
Signs include excessive heating, communication failures, voltage loss, or visible damage to the insulation.
3. Can cables be reused in new installations?
Only if they are in good condition and compatible with the requirements of the new installation. Reuse should always be validated by a qualified technician.
VI. STANDARDS
1. What technical standards must electrical cables comply with?
All cables must comply with standards such as NP EN 50525, IEC 60228, and safety directives such as the CPR (Construction Products Regulation). The CPR standard from the European Union establishes fire safety requirements for construction products, including electrical cables. All the cables we supply strictly comply with CPR, being classified according to their fire performance, ensuring maximum safety for your installations.
1. What technical standards must electrical cables comply with?
All cables must comply with standards such as NP EN 50525, IEC 60228, and safety directives such as the CPR (Construction Products Regulation). The CPR standard from the European Union establishes fire safety requirements for construction products, including electrical cables. All the cables we supply strictly comply with CPR, being classified according to their fire performance, ensuring maximum safety for your installations.
VII. NORTÉCNICA PRODUCTS AND SERVICES
1. Does Nortécnica have cables in stock for fast delivery?
Yes, we offer a wide range of power and signal cables available for 24h delivery.
2. Is technical support available for cable selection?
Yes, our technical team can assist with selection, sizing, and equipment compatibility.
3. Does Nortécnica provide technical training on cabling and best practices?
Yes, we organize technical training on installation, protection, standards, and cabling technologies.
4. Does the company provide custom cable cutting services?
Yes, at Nortécnica we understand the importance of material optimization. We offer custom cable cutting services for most of our cables, allowing you to purchase exactly what you need and reduce waste in your project.
4. What is the procedure to request a quote or check cable availability?
You can contact our sales team through our website, phone, or email. Our team of specialists is ready to help you choose the best solution and provide all the necessary information, including quotations and delivery times.
1. Does Nortécnica have cables in stock for fast delivery?
Yes, we offer a wide range of power and signal cables available for 24h delivery.
2. Is technical support available for cable selection?
Yes, our technical team can assist with selection, sizing, and equipment compatibility.
3. Does Nortécnica provide technical training on cabling and best practices?
Yes, we organize technical training on installation, protection, standards, and cabling technologies.
4. Does the company provide custom cable cutting services?
Yes, at Nortécnica we understand the importance of material optimization. We offer custom cable cutting services for most of our cables, allowing you to purchase exactly what you need and reduce waste in your project.
4. What is the procedure to request a quote or check cable availability?
You can contact our sales team through our website, phone, or email. Our team of specialists is ready to help you choose the best solution and provide all the necessary information, including quotations and delivery times.
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