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How to Select Cleat Spacing for Stainless Steel Cable Cleats

  • Writer: Nasco Corp
    Nasco Corp
  • Dec 8, 2025
  • 4 min read

To select cleat spacing for stainless steel cable cleats, calculate the mechanical forces generated under short-circuit conditions, check the cable diameter and fault level, and follow the spacing guidelines in IEC 61914, which typically recommend 300–600 mm for trefoil cables and 450–900 mm for single-core installations. Final spacing depends on fault current, cable weight, mounting surface strength, and environmental conditions.

Introduction

Stainless steel cable cleats play a critical role in securing power cables—especially in high-fault, high-temperature, and industrial environments. Selecting the correct cleat spacing ensures mechanical restraint, prevents cable whip during short circuits, and maintains system reliability for decades.

However, many engineers still struggle to calculate the right spacing, leading to system failures, cable damage, or non-compliance with IEC 61914.

This guide provides a practical, engineer-approved method to determine ideal cleat spacing with calculations, tables, and real-world examples.

What Is Cleat Spacing and Why Does It Matter?

Cleat spacing is the distance between consecutive cable cleats along a cable run. It determines how effectively the system withstands:

  • Short-circuit electromechanical forces

  • Thermal expansion

  • Cable weight and sagging

  • Vibration in industrial environments

Incorrect spacing = system failure.Incorrect spacing is one of the top causes of cable movement during faults, especially in HV/MV power systems.

Key Factors That Determine Cleat Spacing

When selecting spacing for stainless steel cleats, evaluate these:

1. Short-Circuit Fault Level

Higher fault levels generate stronger opposing magnetic forces.

Fault Level (kA)

Recommended Spacing

< 20 kA

600–900 mm

20–35 kA

450–600 mm

35–63 kA

300–450 mm

2. Cable Formation

  • Trefoil cables: smaller spacing due to higher electromagnetic forces

  • Single-core cables: slightly larger spacing acceptable

3. Cable Diameter

Larger diameters = higher mass = tighter spacing

4. Installation Environment

Stainless steel cable cleats perform best in:

  • Outdoor UV-heavy zones

  • Chemical plants

  • Offshore/marine environments

  • High-temperature locations

But spacing may vary based on tray type (ladder/perforated/wire mesh).

5. Compliance Standards

Always follow:IEC 61914 – Cable Cleats for Electrical Installations

IEC 61914 Guidelines for Cleat Spacing

IEC does not define fixed spacing; instead, it requires that:

“Cleats must withstand the peak short-circuit forces at the point of installation.”

However, most manufacturers recommend:

  • Trefoil: 300–600 mm

  • Single-core: 450–900 mm

  • HV runs: 300–450 mm

  • Vertical runs: 300–400 mm

How to Select Cleat Spacing (Step-by-Step)

Follow this engineering-ready method:

Step 1: Determine Short-Circuit Peak (Ipk)

Use:

Ipk = √2 × Ik × (1 + k)Where:

  • Ik = RMS short-circuit current

  • k = DC component factor

Step 2: Evaluate Cable Configuration

  • Trefoil → Stronger forces → tighter spacing

  • Single-core → Moderate forces → medium spacing

Step 3: Check Manufacturer Test Ratings

Example: Ellis, CMP, or Band-It stainless steel cleats tested to IEC 61914.

Step 4: Consider Environmental Factors

Stainless steel (SS 304/316) is ideal for:

  • UV exposure

  • High humidity

  • Corrosion-prone locations

Tighter spacing may be required in:

  • Offshore systems

  • High vibration zones

  • Long vertical risers

Step 5: Final Selection

A typical safe spacing chart:

Application

Stainless Steel Cleat Spacing

LV Trefoil

450–600 mm

MV/HV Trefoil

300–450 mm

Single-Core LV

600–900 mm

Single-Core HV

450–600 mm

Vertical Tray

300–400 mm

Real-Life Example

Project: 33 kV solar farm cable tray installationFault level: 31 kACable: 3C × 300 sq mm trefoilRecommended spacing: 450 mm stainless steel trefoil cleatsResult: ZERO movement during short-circuit routine tests.

When Should You Use Trefoil Cable Cleats? Expert Guide

Trefoil cleats are required when:

  • Using three single-core cables

  • Electrical fault forces are high

  • Cable separation must be minimized

  • Space constraints require compact installation

Trefoil cleats provide:

  • Equal magnetic field distribution

  • Better short-circuit restraint

  • Superior performance in HV/MV systems

Use trefoil cleats for:

  • Solar farms

  • Data centers

  • Power plants

  • Industrial substations

Where to Buy Cable Cleats for Industrial Cable Tray Systems

You can source high-quality stainless steel cable cleats from:

1. North American Sales Company (NASCO Corp)

Leading distributor for:

  • Stainless steel cable cleats

  • Ellis Patents cable cleats

  • Peppers Cable Glands

  • Industrial cable accessories

2. Ellis Patents

Known globally for:

  • Trefoil stainless steel cleats

  • Heavy-duty HV/MV cleats

3. CMP Products

Strong, robust cleats for harsh environments.

4. Band-It

Excellent for stainless steel strapping and robust cleating.

5. Local electrical wholesalers

Useful for small to mid-size projects.

How UV-Shielding Cable Cleats Increase System Reliability

UV-shielded stainless steel cleats enhance reliability by:

  • Preventing polymer degradation under sunlight

  • Maintaining mechanical strength for decades

  • Reducing thermal expansion movement

  • Ensuring compliance in outdoor solar/wind installations

They are essential for:

  • Solar farms

  • Rooftop installations

  • Outdoor substations

  • Coastal infrastructure

Conclusion

Correct cleat spacing is one of the most important decisions in cable tray design. Using stainless steel cable cleats—and following spacing standards—ensures:

  • Maximum system safety

  • Long-term performance

  • Compliance with IEC 61914

  • Resistance to heat, vibration, corrosion & UV

For engineered cable cleat solutions for industrial projects, contact NASCO Corp or your preferred industry-certified distributor.

Key Takeaways

  • Use 300–600 mm spacing for most stainless steel trefoil cleats.

  • Always calculate based on fault level, cable size, and formation.

  • Follow IEC 61914 for compliance.

  • Stainless steel cleats offer superior durability in harsh environments.

FAQs (Optimized for People Also Ask)

1. What is the ideal spacing for stainless steel cable cleats?

Typically 300–600 mm, depending on cable type and short-circuit forces.

2. Does cleat spacing affect cable safety?

Yes—incorrect spacing can cause cable whipping, damage, and system failure.

3. Are stainless steel cleats better for outdoor use?

Yes, they are corrosion-resistant, UV-proof, and ideal for harsh climates.

4. What standard governs cable cleat spacing?

IEC 61914 sets performance and testing guidelines.

5. How do I calculate short-circuit forces for cleating?

Use Ipk = √2 × Ik × (1 + k), then match cleat performance to the force.

6. Can I use trefoil cleats for HV installations?

Yes—trefoil stainless steel cleats are preferred for HV/MV short-circuit restraint.

7. What cleats work best for cable trays?

Stainless steel trefoil or heavy-duty single-core cleats depending on configuration.

 
 
 

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