Building Wire Selection Guide (IEC Standard): Solid vs Stranded, PVC vs LSZH
Created on 06.15
If you are supplying materials for residential, commercial, or industrial construction projects in Asia, Africa, or the Middle East, you will need building wire — the single-core cables used for internal wiring inside walls, conduits, and trunking.
Unlike North America (which uses THHN/THWN under UL standards), most of Asia, Africa, and the Middle East follows IEC standards (or local adaptations of IEC/BS).
This guide covers the basics of choosing the right building wire for your project — no complicated codes, just practical advice.
First: How Building Wire is Named Under IEC
In the IEC system, building wire is typically referred to by its construction and voltage rating. The most common type is:
H07V-U / H07V-R / H07V-K (European designation, widely accepted internationally)
Here is what the letters and numbers mean:
Code | Meaning |
H | Harmonized type (European) |
07 | 450/750V (common building wire voltage) |
V | PVC insulation |
U | Solid conductor (one piece of copper) |
R | Stranded conductor (several thick strands) |
K | Fine stranded conductor (many thin strands — flexible) |
Outside Europe, these exact codes may not appear on local specs. Instead, you will often see descriptions like:
- *
450/750V single-core PVC insulated copper cable*
- Solid copper conductor, PVC insulated
- Building wire to IEC 60227
The key is not the name — it is the construction (solid vs stranded, copper vs aluminum, insulation material).
Solid vs Stranded vs Fine Stranded: Which One Do You Need?
Building wire comes in three conductor types. Choose based on how the wire will be installed.
Type | Conductor | Flexibility | Best For |
Solid (Class 1) | Single piece of copper | Very stiff | Fixed installation inside conduit — once installed, never moved |
Stranded (Class 2) | 7 to 19 thick strands | Moderate | Conduit runs with bends — still stiff but easier to pull |
Fine stranded (Class 5) | Many thin strands | High | Control panels, frequent bending, tight spaces |
Recommendation for most building projects:
Application | Best Choice |
Residential wall wiring (conduit) | Solid (Class 1) or Stranded (Class 2) |
Commercial building (long conduit runs) | Stranded (Class 2) — easier to pull around bends |
Distribution board internal wiring | Fine stranded (Class 5) — flexible for tight panel wiring |
Temporary / portable wiring | Fine stranded (Class 5) — withstands movement |
Cost order: Solid is cheapest. Fine stranded is most expensive. For most building wire applications, solid or standard stranded is sufficient.
Insulation: PVC vs LSZH
For building wire, PVC insulation is the standard choice. But in some projects, LSZH (Low Smoke Zero Halogen) is specified.
Insulation | Cost | Smoke in Fire | Toxic Gases | Typical Use |
PVC | Lower | Thick black smoke | Releases HCl gas | Standard residential, commercial buildings |
LSZH | Higher (20-40% more) | Low smoke | None | Hospitals, airports, metro stations, high-rise buildings |
When to use LSZH for building wire:
- Project specification explicitly calls for LSZH
- Enclosed public spaces with limited ventilation
- Local building code requires it (some major cities)
When PVC is fine:
- Standard residential or commercial buildings
- Outdoor installations
- Projects where cost is the main concern
*For 80% of building projects in Asia and Africa, PVC is acceptable. LSZH is typically only required for high-profile or government projects.*
Copper vs Aluminum for Building Wire
This is a common question in price-sensitive markets.
Factor | Copper | Aluminum (AA-8000 alloy) |
Cost per meter | Higher | Lower (about 40-50% less) |
Weight | Heavier | Lighter |
Termination | Standard lugs | Requires CO/ALR or bi-metallic lugs |
Small sizes available | Yes (down to 1.5mm²) | Usually from 10mm² and up |
Local acceptance | Universal | Acceptable if properly terminated |
Practical advice for building projects:
Project Type | Recommended Conductor |
House wiring (1.5mm², 2.5mm²) | Copper — aluminum not available in small sizes |
Apartment building feeders (16mm² and up) | Aluminum — cost savings significant |
Commercial building (all sizes) | Copper — unless engineer approves aluminum |
Industrial / warehouse | Aluminum — large conductors, fixed installation |
If you choose aluminum, make sure your electrician knows how to terminate it correctly. Poor termination is the main reason aluminum wiring fails.
Common Sizes and Their Uses
Under IEC, building wire sizes are in mm² (not AWG). Here are the most common sizes for building projects:
Size (mm²) | Ampacity (PVC insulated, 30°C ambient) | Typical Use |
1.5mm² | 15-18A | Lighting circuits, small outlets |
2.5mm² | 20-25A | Power outlets (general use) |
4mm² | 30-35A | Air conditioners, water heaters, ovens |
6mm² | 40-45A | Small sub-circuits, cooktops |
10mm² | 55-65A | Small distribution feeders |
16mm² | 75-85A | Main feeders for apartments |
25mm² | 95-110A | Large feeders, small building mains |
*Note: Actual ampacity depends on installation method (in conduit, clipped direct, etc.) and ambient temperature. For hot climates (40°C+), reduce values by approximately 10-15%.*
Color Codes in Asia & Africa
Different countries have different color codes. Here are the most common:
Standard IEC color code (most common):
Conductor | Color |
Phase (Live) | Brown |
Neutral | Blue |
Earth (Ground) | Green/Yellow stripe |
Alternative (older installations, some countries):
Conductor | Color |
Phase (Live) | Red or Yellow |
Neutral | Black or Blue |
Earth (Ground) | Green or Bare |
Before ordering, always check the local color code with your customer. Incorrect colors can cause inspection failures.
What We Can Supply
We manufacture building wire for residential, commercial, and industrial projects in Asia, Africa, and the Middle East.
Specification | Details |
Standard | Designed to IEC 60227 (PVC insulated) |
Voltage rating | 450/750V |
Conductor | Copper (solid, stranded, or fine stranded) |
Conductor class | Class 1 (solid), Class 2 (stranded), Class 5 (fine stranded) |
Insulation | PVC (standard) or LSZH (upon request) |
Sizes | 1.5mm² to 400mm² (single core) |
Colors | Brown, Blue, Green/Yellow, Red, Black, Grey (as required) |
Temperature range | -15°C to +70°C |
We are a new exporter. We offer competitive pricing, clear communication, and samples for your evaluation.
Contact
Looking for a reliable cable manufacturer? Send us your requirements today. Our export sales team will reply within 12 business hours with a professional quotation.
To help us prepare an accurate quotation, you may reply to our email with:
• Cable Type • Voltage • Conductor Size
• Quantity • Destination Country
Need a quotation urgently? Contact us directly via WhatsApp:+86 15838292863