FAQ
TL;DR: 6 mm² stranded Cu safely carries ≈40 A continuously (IEC 60364)[IEC, 2020]; "Do it with the same cross-section"[Elektroda, kkas12, post #17754727] Short links inside a salon board work with 6 mm² when upstream protection ≤40 A. Why it matters: undersized jumpers overheat, trip clients’ supply, and void insurance audits.
Quick Facts
• IEC 60364-5-52 lists 6 mm² Cu in conduit at 36–40 A, 10 mm² at 50–63 A[IEC, 2020]
• Typical modular device terminals accept max 25 mm² solid/35 mm² stranded conductors (Schneider datasheet A9XPH)[Schneider, 2023]
• 6 mm² Cu costs ≈0.85 €/m; 10 mm² ≈1.30 €/m (EU wholesale Q1 2024)[EUPriceWatch, 2024]
• Ferrules required on every stranded end per EN 60204-1 §13.5[EN 60204-1, 2018]
• PVC insulation softens at 105 °C; loose clamp faults can reach 200 °C in <5 min[UL, 2019]
What conductor size should I use to link devices in a board fed with 5×10 mm²?
Match or nearly match the feeder. Use 10 mm² if space allows; otherwise 6 mm² is acceptable when the upstream breaker ≤40 A and runs are <0.5 m[Elektroda, kkas12, post #17754727][Elektroda, elpapiotr, post #17754795]
Is dropping from 10 mm² to 4 mm² inside the switchgear allowed?
No. Forum experts called a 10 → 4 mm² step “drastic” and discouraged it[Elektroda, elpapiotr, post #17754729] 4 mm² Cu is limited to 25–32 A[IEC, 2020], well below typical salon loads.
Stranded (rope) versus solid wire—what’s better inside boards?
Use finely stranded class 5 conductors. They bend easier, withstand electrodynamic forces, and let you combine two ends in one ferrule[Elektroda, kkas12, post #17766208] Solid wire is harder to route and loosens under vibration.
Do I need ferrules on stranded conductors?
Yes. EN 60204-1 demands sleeves where stranded wires enter screw or cage clamps to assure full contact surface[EN 60204-1, 2018]. “Sleeves necessary.”[Elektroda, kkas12, post #17754649]
Will 10 mm² conductors fit into standard MCB or RCCB terminals?
Most modular devices accept up to 25 mm² solid or 35 mm² stranded, so 10 mm² fits easily[Schneider, 2023]. Always verify datasheet markings embossed near the clamp.
Should the neutral link be the same size as phase links?
Keep the N conductor ≥ phase size. Harmonics in salon gear can load N above phase current; experts “would give 6 mm² especially on N”[Elektroda, osiniak75, post #17754699]
How much current can 6 mm² and 10 mm² copper carry?
In PVC conduit at 30 °C: 6 mm²—36–40 A; 10 mm²—50–63 A[IEC, 2020].
Edge case: What happens if two different-size wires share one clamp?
Mixed cross-sections create uneven pressure, causing hot spots. Tests show joint temperatures hitting 200 °C within five minutes, melting PVC and risking fire[UL, 2019]. “A ‘bad’ contact is 100 % reliable.”[Elektroda, kkas12, post #17766208]
Why are three indicator lights fitted in some domestic boards?
They visualise supply status: 1. Voltage at main switch (FR), 2. FR closed, 3. Voltage after RCD[Elektroda, Łukasz-O, #17764411]. It’s mostly cosmetic but helps quick diagnostics.
How do I crimp and install stranded jumpers?
- Strip 12 mm insulation. 2. Slide the correct-size DIN 46228 ferrule and crimp until hex embossing appears. 3. Insert wire fully, tighten torque to device spec (e.g., 2.8 N·m for 6 mm²).
What is the price impact of choosing 10 mm² instead of 6 mm²?
At current EU wholesale rates, upgrading 1 m of conductor adds about €0.45. For a typical board needing 3 m of links, the cost increase is roughly €1.35[EUPriceWatch, 2024].
Which standards cover internal switchboard wiring?
Key documents: IEC 60364-5-52 (current capacity), EN 60204-1 (terminations), and HD 60364-4-43 (protection against overcurrent). Local regulations may add colour-code or routing rules.
