We offer suggestions for selecting high-flex robot cables for moving part power supplies, including the OKI Electric Cable ORP-D, Hanshin Electric Cable MRC UL2501, and Dyden Robotop DP6.Each cable is sold cut to length.Please refer to the product page via the address link in the middle of the page.
— Technical Comparison and Practical Engineering Guidance —
As industrial automation continues to evolve, the reliability requirements for cables used in moving parts have become increasingly demanding. In robot arms, transfer systems, and cable carrier applications, power cables are subjected to continuous bending, sliding, and torsional stress. In such environments, general-purpose fixed-installation cables are not sufficient. Dedicated robot power cables are essential to ensure long-term operational stability.
This column provides a comprehensive technical overview of selection criteria, including electrical capacity, mechanical durability, and a comparative review of three major Japanese products: OKI Electric Cable ORP-D, Hanshin Cable MRC UL2501, and Dyden Robotop DP6.
Operating Environments and Application Scope
Robot power cables for moving applications are typically installed in:
Industrial robot arms (internal routing)
Transfer and inspection systems with reciprocating motion
Cable carriers (energy chains)
Power supply lines for three-phase motors and servo drives
These applications involve repeated bending cycles that may reach tens of millions or even exceed one hundred million cycles. Mechanical stress is often the primary failure factor, making conductor structure, insulation material, and sheath durability critical design elements.
Why Dedicated Robot Power Cables Are Required
Mechanical Durability Under Repeated Motion
Robot cables use finely stranded conductors and optimized internal structures to resist bending fatigue. Compared to standard power cables, they are engineered to withstand long-term dynamic operation.
UL Compliance for Global Equipment
All three products discussed in this article are rated at 600V and 105°C in accordance with UL758 standards. For equipment exported to North America or used in globally standardized production lines, UL compliance is often mandatory.
Shielded and Unshielded Variants
In inverter-driven systems or installations where power and signal cables are routed together, electromagnetic noise becomes a design consideration. Shielded models reduce noise interference, while unshielded versions provide improved flexibility and reduced cable weight.
Specification Comparison of Three Major Products
The following products are widely recognized in Japan for moving power cable applications:
OKI Electric Cable ORP-D
Hanshin Cable MRC UL2501
Dyden Robotop DP6
Key Specification Overview
| Item | ORP-D | MRC UL2501 | Robotop DP6 |
|---|
| Standard | UL758 Style 2586, 105°C, 600V | UL758 Style 2501, 105°C, 600V | UL758 Style 2501, 105°C, 600V |
| AWG Range | AWG21 to AWG12 (0.5–5.5 mm²) | AWG18 to AWG10 | AWG18 to AWG4 (depending on series) |
| Core Count | 2 to 10 cores | 2 to approx. 20 cores | 2 to approx. 30 cores |
| Shielding | Available (shielded / unshielded) | Available (shielded / unshielded) | Primarily unshielded (shielded versions available in other series) |
| Recommended Bending Radius (moving use) | 6–8 × overall diameter | Approx. 6 × overall diameter | Typically around 6 × overall diameter (varies by size) |
Although all three products share the same 600V and 105°C rating, their design focus and lineup breadth differ significantly.
Allowable Current and Conductor Selection
Allowable current depends primarily on conductor size (AWG) and installation conditions.
As general engineering references:
AWG12 class: approximately 20A
AWG10 class: approximately 30A
Larger conductors (e.g., AWG4): suitable for higher current motor applications
When selecting conductor size, engineers must consider:
Proper derating calculations are necessary, especially in enclosed cable carriers or high-temperature environments.
Recommended Minimum Bending Radius
For dynamic applications, a commonly accepted engineering guideline is:
Designing below this limit accelerates conductor fatigue and insulation degradation. In robot arm design, sufficient routing space must be secured at the mechanical design stage to prevent premature failure.
Product Positioning and Application Suitability
OKI Electric Cable ORP-D
ORP-D emphasizes reduced outer diameter and high flexibility. It is particularly suitable for compact robotic systems and installations where routing space is restricted. The availability of shielded and unshielded models allows flexibility in addressing noise-sensitive environments.Available in shielded and unshielded versions.
ORP-D Shielded (SB) Power Supply Robot Cable UL2586 105°C 600V
https://nisho-en.ocnk.net/product-list/46
ORP-D Unshielded Power Supply Robot Cable UL2586 105°C 600V
https://nisho-en.ocnk.net/product-list/47
Hanshin Electric Cable MRC UL2501
MRC UL2501 focuses on enhanced bending and torsional resistance. It is well suited for applications involving higher mechanical stress or complex motion patterns. Shielded variants provide additional protection in inverter-driven or noise-prone systems.Available in shielded and unshielded versions.
MRC UL2501 105°C 600V Shielded (SB)
https://nisho-en.ocnk.net/product-list/86
MRC UL2501 105°C 600V Unshielded
https://nisho-en.ocnk.net/product-list/85
Dyden Robotop DP6
Robotop DP6 offers a broad lineup in conductor sizes and core counts. It is appropriate for general-purpose moving power applications, including cable carrier systems and factory automation equipment. Its versatility makes it suitable for a wide range of electrical load conditions.
Robotop DP*6 UL2501 105°C 600V Unshielded
https://nisho-en.ocnk.net/product-list/92
*Images are for reference only.
Engineering Selection Checklist
When selecting a robot power cable for moving applications, engineers should verify:
Continuous and peak current requirements
Required bending cycle life and motion speed
Stroke length and routing constraints
Noise environment and shielding necessity
Compliance requirements (UL, CSA, etc.)
A robot power cable in a moving system functions not only as an electrical component but also as a mechanical element under continuous stress. Electrical capacity alone is not sufficient for proper selection; mechanical endurance must be evaluated with equal importance.
Conclusion
In automated systems, long-term reliability is often determined by components that are not visible—such as internal power cabling. Selecting an appropriate robot power cable directly impacts equipment durability, maintenance frequency, and operational safety.
A careful balance of electrical performance, mechanical flexibility, environmental resistance, and installation constraints ensures stable operation throughout the lifecycle of the equipment.
