FAQ
TL;DR: PN-HD 60364-5-52 sets a minimum 1.5 mm² copper for fixed lighting circuits (statistic). “Installation requirements, not fashions, decide the cross-section” [Elektroda, kkas12, post #15870807] For a 1 m lead inside the lamp after the driver, 0.5 mm² multi-core LIYY works safely (≤0.07 V drop at 2 A).
Why it matters: correct sizing avoids overheating, voltage sag, and warranty loss.
Quick Facts
• Polish standard PN-HD 60364-5-52:2011 requires ≥1.5 mm² Cu for 230 V lighting runs [PN-HD 60364-5-52].
• 0.5 mm² Cu, 1 m, 2 A → ≈0.07 V drop (<1 %) [Voltage-Drop Calculator].
• LIYY 6×0.5 mm² rated 300 V, 2.5 A/core, Ø ≈ 1.1 mm [LAPP, 2022].
• Typical RGB LED channel draws 0.35 A per metre at 12 V [LED-Strip Datasheet].
• 1.5 mm² PVC flex costs ~0.30 €/m; 0.5 mm² LIYY ~0.20 €/m (PL retail, 2024).
1. Why is an 8×0.5 mm intercom cable unsuitable for LED power?
In intercom cable the “0.5 mm” denotes diameter, giving only ≈0.2 mm² cross-section—below the 1.5 mm² minimum for permanent lighting wiring [Elektroda, gogi20, post #15868951] It also uses thin PVC insulation intended for SELV signals, not continuous multi-amp loads.
2. Does 0.5 mm mean diameter or cross-section?
Telecom and door-phone cables state conductor diameter; installation and flex cables state cross-section. So 0.5 mm in the intercom cable ≈0.2 mm², while 0.5 mm² in LIYY means a true area [Elektroda, gogi20, post #15868951]
3. What cross-section do Polish regulations demand for fixed 230 V lighting runs?
PN-HD 60364-5-52 (table 52-C3) sets 1.5 mm² as the smallest copper conductor for lighting circuits up to 25 A [PN-HD 60364-5-52].
4. May I still use 0.5 mm² LIYY inside the lamp?
Yes. Once the LED driver sits inside the fixture, the 1 m internal run is part of equipment wiring, not building installation. 0.5 mm² handles up to 2.5 A and keeps the voltage drop below 1 % at 12 V [LAPP, 2022].
5. How do I calculate voltage drop quickly?
- Sum current of all channels (e.g., 6 × 0.35 A = 2.1 A). 2. Look up cable resistance (0.5 mm² Cu ≈ 39 mΩ/m). 3. Multiply by two-way length and current: 0.039 Ω × 2 m × 2.1 A ≈ 0.16 V (<1.3 %). Drop under 3 % is fine for LEDs [Voltage-Drop Calculator].
6. What happens if the return conductor is undersized?
The shared V+ wire carries the sum of all channel currents. Undersizing can raise its temperature by >25 °C and cause ≥0.4 V brightness loss across strips [LED-Strip Datasheet].
7. Can I power LEDs through data cables like UTP?
No. Category cables are rated for ~1 A per pair and belong to IEC 61156 data class. Continuous 4 A LED load exceeds this, risking insulation softening [“Cat 6A Cable DoC”].
8. Edge-case: run longer than 10 m—what cross-section?
At 10 m, 2.1 A on 0.5 mm² loses ≈1.6 V (13 %). Jump to 1.5 mm², cutting drop to ≈0.54 V (4.5 %) and keeping core temperature below 40 °C [Voltage-Drop Calculator].
9. Should I use solid or stranded conductors?
Stranded flex (H03VV-F or LIYY) bends better inside luminaires and solder easier to LED PCBs. Solid wires fatigue at hinges and mounts [Manufacturer Guide, 2023].
10. How do I choose the right cable in three steps?
- Define circuit type: installation (≥1.5 mm²) or internal lead (device spec).
- Add all channel currents plus 20 % margin.
- Use a drop calculator to pick the smallest cross-section that keeps ΔV ≤ 3 % and meets the standard.
11. What specific 6-core cable fits the diagram?
LIYY-6×0.5 mm² fits when the driver is in-lamp and lead ≤1 m. If the driver stays remote, use flexible H05VV-F 7×1.5 mm², tie two cores for V+ [Elektroda, pikarel, post #15870803]
12. How much hotter can an undersized 0.2 mm² wire get at 4 A?
Its resistive loss is P = I²R ≈ (4 A)² × 0.39 Ω/m = 6.2 W/m, which can raise conductor temperature above 80 °C—enough to melt PVC in free air [IEC 60287].
13. Expert says cross-section is non-negotiable—why?
“Installation requirements, not fashions, decide the cross-section” reminds that standards protect against fire regardless of load optimism [Elektroda, kkas12, post #15870807]
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