Light Duty vs Medium Duty vs Heavy Duty Cable Trays — Which Do You Need?
, by Reino Retief, 8 min reading time
Not sure which cable tray to use? This guide explains the difference between light, medium and heavy duty cable trays for South African electricians and contractors.
Light Duty vs Medium Duty vs Heavy Duty Cable Trays — Which Do You Need?
If you've ever stood on a job site trying to decide between light duty, medium duty and heavy duty cable trays, you're not alone. It's one of the most common questions electricians, contractors and project managers ask — and getting it wrong means either an undersized tray that can't handle your cable load, or an oversized, overpriced solution that eats into your project budget.
This guide breaks it down clearly so you can specify and order the right cable tray first time, every time.
What Is A Cable Tray?
A cable tray is a rigid structural system used to support and route electrical cables in commercial, industrial and infrastructure installations. Unlike cable trunking — which fully encloses cables — a cable tray supports cables from below while keeping them accessible for inspection, maintenance and future additions.
Cable trays are used extensively across South Africa in factories, warehouses, commercial buildings, mining operations, data centres and infrastructure projects. They are manufactured from slotted steel and supplied in standard 3 metre lengths, with a full range of accessories including bends, tees, reducers and brackets.
The Three Types — At A Glance
| Specification | Light Duty (LDCT) | Medium Duty (MDCT) | Heavy Duty (HDCT) |
|---|---|---|---|
| Tray Depth | 12mm | 38mm | 76mm |
| Available Widths | 50mm–304mm | 76mm–609mm | 76mm–609mm |
| Standard Length | 3m | 3m | 3m |
| Slot Size | 25 x 6.5mm | 25 x 11mm | 25 x 11mm |
| Typical Use | Light commercial | Industrial & commercial | Mining & heavy industrial |
| Load Capacity | Light | Medium-heavy | Maximum |
Light Duty Cable Trays (LDCT Series)
What Makes It "Light Duty"?
Light duty cable trays have a 12mm tray depth and are manufactured from lighter gauge steel — designed for installations where cable volumes are manageable and structural loads are modest. Available in 7 widths from 50mm up to 304mm in standard 3 metre lengths.
When To Use Light Duty Cable Trays:
- Commercial office buildings and retail fit-outs
- Residential estate and apartment block electrical installations
- Above-ceiling cable routing in light commercial buildings
- Data and communication cable management (CAT6, fibre)
- Any installation with a small to moderate number of cables
- Installations where tray widths up to 304mm are sufficient
When NOT To Use Light Duty:
- Industrial environments with large cable bundles
- Any application requiring widths above 304mm
- Installations with heavy power cables (25mm² and above)
- Mining or petrochemical environments
Available Sizes (LDCT Series):
- LDCT50S — 50mm wide x 12mm deep x 3m
- LDCT76S — 76mm wide x 12mm deep x 3m
- LDCT101S — 101mm wide x 12mm deep x 3m
- LDCT152S — 152mm wide x 12mm deep x 3m
- LDCT203S — 203mm wide x 12mm deep x 3m
- LDCT228S — 228mm wide x 12mm deep x 3m
- LDCT304S — 304mm wide x 12mm deep x 3m
→ Shop Light Duty Cable Trays at Maple Leaf Electrical
Medium Duty Cable Trays (MDCT Series)
What Makes It "Medium Duty"?
Medium duty cable trays have a 38mm tray depth — more than three times deeper than light duty — and are manufactured from heavier gauge steel for greater structural rigidity and load-bearing capacity. Available in 7 widths from 76mm up to 609mm in standard 3 metre lengths.
When To Use Medium Duty Cable Trays:
- Industrial factories, warehouses and manufacturing plants
- Commercial buildings with high cable fill requirements
- Data centres and server room cable management
- Installations requiring widths from 228mm to 609mm
- Any installation with heavier power cable bundles
- HVAC and building services cable routing
- Infrastructure projects and large commercial developments
When To Choose Medium Over Light Duty:
- Your cable bundle depth exceeds 12mm
- You need tray widths wider than 304mm
- The installation is in an industrial or semi-industrial environment
- Cables include larger conductor sizes (16mm² and above)
- Long unsupported spans are required between brackets
Available Sizes (MDCT Series):
- MDCT76S — 76mm wide x 38mm deep x 3m
- MDCT114S — 114mm wide x 38mm deep x 3m
- MDCT152S — 152mm wide x 38mm deep x 3m
- MDCT228S — 228mm wide x 38mm deep x 3m
- MDCT304S — 304mm wide x 38mm deep x 3m
- MDCT457S — 457mm wide x 38mm deep x 3m
- MDCT609S — 609mm wide x 38mm deep x 3m
→ Shop Medium Duty Cable Trays at Maple Leaf Electrical
Heavy Duty Cable Trays (HDCT Series)
What Makes It "Heavy Duty"?
Heavy duty cable trays have a 76mm tray depth — double that of medium duty — and are manufactured from the thickest gauge steel in the range, engineered for maximum load-bearing capacity and structural strength in the most demanding electrical installation environments. Available in widths from 76mm up to 609mm in standard 3 metre lengths.
When To Use Heavy Duty Cable Trays:
- Mining and minerals processing plants
- Petrochemical, oil and gas installations
- Heavy industrial factories with large power cable bundles
- Power stations and high-voltage substations
- Large infrastructure and civil engineering projects
- Any installation requiring maximum tray depth (76mm)
- Environments subject to mechanical stress, vibration or impact
- Long unsupported cable tray spans between support brackets
When To Choose Heavy Duty Over Medium Duty:
- Your cable bundle depth exceeds 38mm
- The environment is mining, petrochemical or heavy industrial
- Maximum structural rigidity is required
- Cables include very large conductor sizes (95mm² and above)
- The installation is subject to harsh conditions or vibration
Available Sizes (HDCT Series):
- HDCT76S — 76mm wide x 76mm deep x 3m
- HDCT114S — 114mm wide x 76mm deep x 3m
- HDCT152S — 152mm wide x 76mm deep x 3m
- HDCT228S — 228mm wide x 76mm deep x 3m
- HDCT304S — 304mm wide x 76mm deep x 3m
- HDCT457S — 457mm wide x 76mm deep x 3m
- HDCT609S — 609mm wide x 76mm deep x 3m
→ Shop Heavy Duty Cable Trays at Maple Leaf Electrical
The Simple Decision Guide
Not sure which one you need? Use this quick decision guide:
Choose Light Duty (LDCT) if:
✅ Commercial or residential installation
✅ Cable bundle is shallow (under 12mm deep)
✅ Tray width of 304mm or less is sufficient
✅ Budget is a priority on a lighter-load project
Choose Medium Duty (MDCT) if:
✅ Industrial or heavy commercial installation
✅ Cable bundle depth is between 12mm and 38mm
✅ Tray widths up to 609mm are required
✅ Heavier power cables (16mm² and above) are being routed
Choose Heavy Duty (HDCT) if:
✅ Mining, petrochemical or heavy industrial installation
✅ Cable bundle depth exceeds 38mm
✅ Maximum load-bearing capacity is required
✅ Long unsupported spans or harsh environments are involved
How To Size Your Cable Tray Width
Selecting the correct tray width is just as important as selecting the correct duty rating. A tray that is too narrow restricts future cable additions and reduces airflow around cables — which can cause cables to run hot and reduce their current-carrying capacity.
As a general rule, your cables should only fill 60% of the tray width — leaving 40% spare for future cables and airflow. This is in line with standard South African electrical installation practice and IEC cable tray loading guidelines.
Example: If your cable bundle measures 150mm wide, select a 228mm or 304mm wide tray — not a 152mm tray that your cables exactly fill.
Cable Tray Accessories
A complete cable tray installation requires more than just straight tray lengths. Make sure you also specify the correct accessories for your installation:
- Bends (horizontal and vertical) — for routing around corners and obstacles
- Tees and cross pieces — for branching cable runs
- Reducers — for transitioning between different tray widths
- End caps — for finishing open tray ends neatly
- Brackets and supports — for wall and ceiling mounting
- Gutter nuts and bolts — for joining tray sections
- Earthing straps — for bonding tray sections for continuity
Where To Buy Cable Trays Online In South Africa
Maple Leaf Electrical Supplies stocks light duty, medium duty and heavy duty cable trays with fast nationwide delivery across all 9 provinces. All trays are supplied in standard 3 metre lengths and priced per length — with contractor and bulk pricing available on larger quantities.
- → Light Duty Cable Trays (LDCT) — 50mm to 304mm wide
- → Medium Duty Cable Trays (MDCT) — 76mm to 609mm wide
- → Heavy Duty Cable Trays (HDCT) — 76mm to 609mm wide
Contact us for contractor and bulk pricing:
📧 sales@mapleleafelectrical.co.za
📞 064 086 3515
Fast nationwide delivery across South Africa. Orders dispatched same day where possible.
Disclaimer: Cable tray selection and installation must be carried out by a competent person in accordance with SANS 10142 and applicable South African electrical installation standards. Always consult a registered electrician or electrical engineer for specification on large or complex installations.