Cable Lug Sizing Basics
Selecting the correct cable lug size is crucial for safe and efficient electrical connections. This guide explains how to read size charts and make the right choice.
Key Dimensions
1. Cable Size (sq mm)
The cross-sectional area of the conductor, measured in square millimeters. Common sizes:
- Small: 1.5, 2.5, 4, 6 sq mm
- Medium: 10, 16, 25, 35, 50 sq mm
- Large: 70, 95, 120, 150, 185, 240, 300 sq mm
- Extra Large: 400, 500, 630 sq mm
2. Hole Size (mm)
The mounting hole diameter on the lug palm. Industry standard hole sizes:
| Cable Size (sq mm) | Standard Hole Size (mm) |
|---|---|
| 1.5 - 2.5 | 4 - 5 |
| 4 - 6 | 6 |
| 10 - 16 | 8 |
| 25 - 50 | 10 |
| 70 - 95 | 12 |
| 120 - 150 | 14 |
| 185 | 16 |
| 240 - 300 | 17 |
| 400 - 630 | 21 |
3. Barrel Dimensions
- Inside Diameter: Must accommodate the conductor strands
- Barrel Length: Short, medium, or long barrel options
Understanding Catalog Numbers
Dowell's catalog numbers encode the lug specifications:
CUS Series (Copper Medium Duty)
Example: CUS-17
- CUS = Copper Tube Terminal Medium Duty
- 17 = Sequential product number (70 sq mm, 12mm hole)
CBS Series (Copper Heavy Duty)
Example: CBS-27
- CBS = Copper Tube Terminal Heavy Duty BS4579
- Designed for heavy-duty crimping
Sector vs Round Conductors
For cables above 16 sq mm, conductors may be sector-shaped:
- Round conductors: Use standard tube terminals
- Sector conductors: Use sector-specific lugs for proper contact
3.5 Core Cable Special Case
For 3.5 core cables with reduced neutral:
- 3 phases at full size (e.g., 70 sq mm)
- 1 neutral at half size (e.g., 35 sq mm)
- Order lugs in both sizes!
Quick Selection Tips
- Always match lug size to cable cross-section
- Check bolt size on your busbar for hole diameter
- Choose barrel length based on crimping tool capability
- For sector cables, specify conductor shape when ordering
Use our Quote Generator for automatic size matching based on your cable specifications.
Tags
#cable lugs#size chart#specifications#selection guide