A Simple Guide for Homes, Villas, and Projects in Bali
Choosing the right electrical cable size is one of the most important parts of any installation. Too small, and you risk overheating, voltage drop, and equipment damage. Too large, and you overspend unnecessarily.
At Bali Building Solutions (BBS), we often see confusion around cable sizes, so here is a simple, practical guide to help you choose the right one for your project.
Understanding Cable Sizes
Cable sizes are measured in mm² (square millimeters), which refers to the thickness of the conductor.
The larger the number:
- The more electricity it can safely carry
- The more suitable it is for heavier loads
Lighting Circuits
For standard lighting such as downlights, wall lights, and LED strips:
Recommended size: 1.5 mm²
Typical cables:
- NYM 2×1.5 or 3×1.5
- NYA (installed inside conduit)
This size is efficient, cost-effective, and suitable for low power demand.
Power Sockets (General Use)
For everyday outlets powering TVs, chargers, and kitchen appliances:
Recommended size: 2.5 mm²
Typical cables:
- NYM 3×2.5
This is the most commonly used cable size for general power sockets and provides reliable performance for multiple devices.
Air Conditioning and Medium Loads
For equipment such as air conditioning units, water heaters, and pumps:
Recommended size: 4 mm² – 6 mm²
Typical cables:
- NYM 3×4
- NYY 3×4 (for outdoor use)
These sizes handle higher electrical loads and reduce the risk of overheating.
Sub-Main Distribution
For power running between panels or buildings, such as from a main distribution board to a sub-panel:
Recommended size: 6 mm² – 10 mm²
Typical cables:
- NYY 2×6 or 3×6
- NYY 2×10 or 3×10
These cables ensure stable power distribution across larger systems.
Main Incoming Power
For the main electrical supply entering a property:
Recommended size: 10 mm² – 16 mm²
Typical cables:
- NYY 2×10
- NYY 2×16
These are designed for high load capacity and are essential for safety and reliability.
Outdoor and Underground Installations
For garden lighting, external power lines, and underground cables:
Always use NYY cable, which is designed for outdoor conditions.
Typical sizes:
- Lighting: 2.5 mm²
- Pumps and equipment: 4–6 mm²
NYY cables are resistant to moisture, sunlight, and environmental exposure.
Control Systems and Panels
For pump systems, automation, and electrical panels:
Use multi-core control cables
Typical sizes:
- 0.75 mm² – 1.5 mm²
These cables help keep wiring organised and reduce installation complexity.
Earthing and Grounding
For electrical safety systems:
Use bare copper (BC cable)
Typical sizes:
- 16 mm² – 35 mm²
These cables are essential for grounding and protecting against electrical faults.
Important Safety Notes
- Use 3-core cables (with earth) where possible
- Outdoor installations should use NYY cable
- NYA cables must always be installed inside conduit
- If unsure, selecting a slightly larger cable size is generally safer
Need Help Choosing?
At Bali Building Solutions (BBS), we do more than supply materials. We help ensure the correct products are selected for each application.
If you are unsure which cable size is right for your project, our team can assist based on your load requirements, installation type, and overall scope.
Contact us to ensure your electrical system is safe, efficient, and built to last.