Solid vs Stranded Conductor — Which One to Choose?

You‘re reviewing a cable specification for an industrial project. The drawing calls for “Class 2 stranded conductor.“ You‘re not sure if that‘s a firm requirement or if a Class 1 solid conductor would work just as well.

This is a common question in LV cable procurement.

Here‘s what you need to know to make the right choice.

Part I: What Are Solid and Stranded Conductors?

IEC 60228 classifies cable conductors by their construction:

• Class 1 (solid conductor) : A single metal wire. Simple construction, lower cost, high mechanical strength. Suitable for fixed installations where flexibility is not required.
• Class 2 (stranded conductor) : Multiple metal wires twisted together. More flexible than solid conductors. Used in fixed installations where some flexibility is needed — especially in larger cross-sections.
• Class 5 (flexible conductor) : Even finer wires twisted together. Designed for applications requiring frequent bending.

A quick way to understand the relationship: Both Class 1 and Class 2 are intended for fixed installations, but Class 2 is noticeably more flexible. If your project requires frequent bending or movement, you‘ll need to consider Class 5 or Class 6 conductors.

Why this matters: Understanding conductor classification helps you read and interpret technical specifications correctly — and know when a spec can be adjusted.

Part II: Flexibility — Why Stranded Conductors Are Easier to Work With

The biggest difference between solid and stranded conductors is flexibility.

• Solid conductor: Rigid. Cannot be bent repeatedly. Once bent beyond its limit, it may fracture.
• Stranded conductor: Multiple wires can slide past each other, distributing stress across many individual strands. Much more flexible — and much more resistant to fatigue from bending and vibration.

Why this matters for procurement:

If your cable needs to run through tight spaces, along curved paths, or through conduit bends, a stranded conductor is easier to install. If the installation is straight and the cable won‘t move after installation, a solid conductor works just fine — and costs less.

Part III: Installation and Termination — The Trade-Off

Installation convenience:

Stranded conductors are easier to pull through conduit, bend around corners, and route in tight spaces. Electricians generally prefer them for complex installations because they require less force and are more forgiving.

Termination reliability:

Solid conductors terminate more simply and reliably. When tightened under a screw terminal, the solid wire stays put. Contact resistance remains stable over time.

Stranded conductors require more care during termination. The fine wires can splay, break, or loosen over time if not terminated correctly. They typically require ferrules or specialised connectors to ensure reliable connections — adding a small step to the installation process.

The trade-off:

Stranded conductors are easier to install but require more attention during termination. Solid conductors are harder to install but more reliable once terminated.

Part IV: Electrical Performance — Not the Deciding Factor

At the same nominal cross-section, solid and stranded conductors have the same DC resistance limits. The standards (IEC 60228) specify the same maximum resistance values regardless of construction.

In most LV fixed installations — especially at power frequencies (50/60Hz) — the electrical performance difference between solid and stranded conductors is negligible. It is rarely the deciding factor in conductor selection.

Why this matters: Don‘t get distracted by electrical performance comparisons. In most practical applications, the choice comes down to installation requirements, not electrical properties.

Part V: How to Choose — A Simple Decision Framework

Step 1: Will the cable move after installation?

• No → Both solid and stranded work
• Vibration or slight movement expected → Stranded (Class 2) preferred
• Frequent bending or flexing → Class 5 or Class 6 required

Step 2: Is the installation path complex?

• Straight runs, open trays → Solid (Class 1) is cost-effective
• Conduit bends, limited space, awkward routing → Stranded (Class 2) recommended

Step 3: What type of termination?

• Screw terminals, simple compression → Solid is more reliable
• Vibration-prone environment or frequent connection changes → Stranded

Quick Reference:

Decision Factor	Choose Class 1 (Solid)	Choose Class 2 (Stranded)
Installation path	Straight runs, fixed installation	Conduit bends, tight spaces, complex routing
Post-installation movement	None expected	Vibration or slight movement expected
Termination	Screw terminals, simple compression	Ferrules, vibration-resistant connectors
Cost priority	Cost-sensitive projects	Installation efficiency prioritised
Typical applications	Building backbone cabling, residential electrical	Control cabinet wiring, industrial equipment connections

Our Low Voltage Cable Capability

CN Cable Group manufactures LV cables with all three conductor classes per IEC 60228:

Class 1 (solid) : Fixed installation, straight-line cabling, building backbone cabling

Class 2 (stranded) : Industrial power distribution, installations requiring some flexibility

Class 5 (flexible) : Control cabinet wiring, cable carriers, frequent flexing applications

View the full product catalogue:

https://www.cncablegroup.cn/products/

For conductor selection support or project-specific requirements:

Tel: +8613598056591

WhatsApp: +8613598056591

Email: [email protected]