Introduction
Calculating the correct quantities of cable accessories is essential for project planning and cost estimation. This guide covers the formulas and methods used by electrical professionals.
The Core Multiplier Formula
The fundamental formula for calculating cable lug quantities:
Lugs Required = Number of Cable Ends × Number of Cores
Examples
| Cable Type | Cable Ends | Cores | Lugs Needed |
|---|---|---|---|
| Single Core | 10 | 1 | 10 |
| 3 Core | 10 | 3 | 30 |
| 4 Core | 10 | 4 | 40 |
3.5 Core Cable Special Calculation
For 3.5 core cables with reduced neutral:
Full-size lugs: Cable Ends × 3
Half-size lugs: Cable Ends × 1
Half-size = Cable Size ÷ 2
Example: 70 sq mm, 3.5 core, 10 cables
- 70 sq mm lugs: 10 × 3 = 30 pieces
- 35 sq mm lugs: 10 × 1 = 10 pieces
- Total: 40 lugs
Cable Gland Calculation
Cable glands are simpler:
Glands Required = Number of Cable Entry Points
Usually 1 gland per cable, but consider:
- Both ends if terminating in junction boxes
- One end if terminating on open busbars
- Extra 5-10% for spares
Complete Project Calculation Example
Project: Panel board with 20 incoming cables
- 10 × 4 core 25 sq mm cables
- 5 × 3.5 core 70 sq mm cables
- 5 × single core 95 sq mm cables
Lugs Calculation
- 25 sq mm lugs: 10 cables × 4 cores = 40 pieces
- 70 sq mm lugs: 5 cables × 3 cores = 15 pieces
- 35 sq mm lugs: 5 cables × 1 core = 5 pieces
- 95 sq mm lugs: 5 cables × 1 core = 5 pieces
Glands Calculation
Total cable entries: 20 glands
Pro Tips
- Add 10% spare: Always order extras for crimping practice and replacements
- Check both ends: Some cables terminate differently at each end
- Verify sizes early: Confirm cable specs before ordering
- Consider bi-metallic: Needed for Al cable to Cu busbar connections
Automate Your Calculations
Our Quote Generator automatically calculates quantities using these formulas. Simply enter your cable specifications and get an instant quote with all accessories.
Tags
#calculation#project planning#core multiplier#quantities