Detailed Description
Why 40 Cores? The Density Economics of Multi-Conductor Cable
Running 40 individual single-core cables through a drag chain is impractical — the bundle would exceed carrier cross-section limits, the cables would tangle, and the installation labor would be prohibitive. Running 4 × 10-core cables is better, but still requires managing 4 separate cables that can twist around each other.
A single 40-core cable solves all three problems at once:
- Carrier space: A 16 mm OD cable carries 40 signals in ~200 mm² of cross-section. Four 10-core cables at 10 mm OD each would occupy ~315 mm² — 57% more space
- Installation labor: One cable pull and one set of terminations vs four. For a 20 m carrier run, this saves approximately 2–3 hours of installation time
- Organization: One numbered sheath vs four cables to label, bundle, and manage. No risk of mixing up "cable A" and "cable B" during maintenance
High-Density Stranding — Engineering Compact Reliability
Packing 40 cores into a round cable requires precise stranding geometry. The standard structure:
Layer Structure
- Central filler: PP or jute yarn, ~3 mm diameter — provides a round, stable substrate
- Layer 1 (inner): 6–8 cores stranded around the central filler with short lay length
- PET fleece wrap: Thin non-woven tape separates Layer 1 from Layer 2 — prevents core abrasion between layers
- Layer 2 (middle): 12–14 cores stranded counter-direction to Layer 1
- PET fleece wrap: Second separation layer
- Layer 3 (outer): 16–20 cores stranded counter-direction to Layer 2
- Final PET wrap: Overall inner wrap before jacket extrusion
Thin-Wall Insulation
Standard PVC insulation for power cables is 0.5–0.8 mm thick. For 40-core signal cables, the insulation is reduced to 0.2–0.3 mm — still providing >1 500 V dielectric strength, but significantly reducing the overall cable diameter. This is possible because the cores carry low-voltage signals (typically 24 V DC), not mains power.
Core Identification — Reading 40 Numbers
With 40 cores in one sheath, unambiguous identification at both ends is mandatory. Two systems are used:
Option 1: Printed Numbers (VDE 0293 Standard)
Black cores with white ink-jet printed numbers 1 through 40. Each core is individually readable. This is the standard for European machine wiring.
Option 2: Color Coding (DIN 47100)
Colors repeat in sequence: white, brown, green, yellow, gray, pink, blue, red, black, violet, gray-pink, red-blue, white-green, brown-green, white-yellow, yellow-brown, white-gray, gray-brown, white-pink, pink-brown — then repeat. 40 cores typically use 2 color sequences of 20 colors each, distinguished by a printed ring or stripe on the second sequence.
Recommendation: Use printed numbers for permanent installations where the cores terminate at numbered terminals. Use color coding for mobile/portable applications where the cable may be re-terminated and the numbered sequence could be disrupted.When 40-Core Is the Right Choice
| If Your Application... | Then Consider... |
|---|---|
| 30–45 signal points | ✅ 40-core is optimal (some spare) |
| 15–25 signal points | 25-core or 2 × 12-core may be more cost-effective |
| 50+ signal points | 2 × 25-core or 40-core + 12-core combination |
| Mixed power (2.5 mm²) and signal (0.25 mm²) | Composite cable with mixed gauges — not 40 equal cores |
| High-speed data (Ethernet, CAN) | Dedicated data cable — do not bundle in 40-core |
Installation — Managing 40 Wires at Termination
Terminating a 40-core cable requires planning:
- Label BEFORE cutting to length: Confirm all 40 numbers are visible along the entire cable before installation. A single missing number becomes a time-consuming tracing exercise at termination
- Terminal block layout: Pre-print a terminal block layout diagram with core numbers mapped to terminal positions. Laminated A4 sheet at the panel door — the technician should never have to guess
- Service loop: Leave a 300–500 mm service loop at each end. If a core is accidentally cut too short during termination, the service loop provides slack for re-termination without replacing the entire cable
- Ground unused cores: Any cores not used in the current configuration should be grounded at one end. Floating unused cores can capacitively couple noise into active signal cores
- Strain relief at both ends: Use a cable gland with integrated strain relief — 40 × 0.25 mm² cores collectively have minimal tensile strength. Clamping the jacket in a standard PG gland without strain relief will eventually pull out
Why Choose Yichi Cable 40-Core?
- Layer-separated stranding: PET fleece between every conductor layer is standard — prevents the internal abrasion that causes inter-layer short circuits in high-density cables
- Number verification: Every production batch is tested for sequential core numbering — no missing numbers, no duplicate numbers, no illegible printing
- Thin-wall insulation reliability: Our PVC and PP thin-wall insulation is production-tested for pinhole-free extrusion before stranding — a single pinhole in a 40-core cable means scrapping the entire cable after termination
- Compact OD: 14–18 mm OD for 40 × 0.25 mm² — fits standard industrial glands without adapters
- Custom core mix: Need 20 × 0.25 mm² + 10 × 0.50 mm² + 10 × 0.14 mm² in one cable? We build mixed-gauge multi-core to your specification