When it comes to underground cabling, one of the most common and crucial questions we hear is: how deep should an electrical cable be buried? Whether you’re a homeowner looking to run power to a shed, or a builder managing large-scale developments, understanding the proper cable depth is essential for safety, compliance, and long-term performance.
At Connex Electrical, we’ve helped hundreds of clients across Brisbane and surrounding areas get underground power installed the right way first time, every time. Backed by years of industry knowledge, we’ll break this down in simple terms, so you know what’s required and why depth matters.
Why Cable Burial Depth Matters
Burying electrical cables isn’t just about hiding wires. The depth of an underground cable directly impacts:
Electrical safety for people and pets
Protection from mechanical damage (e.g., from gardening or digging)
Compliance with AS/NZS 3000 Wiring Rules (Australian Standards)
Future access for repairs or extensions
If buried too shallow, cables risk being damaged or becoming a hazard. If buried too deep, you could waste labour and risk missing required safety setups like warning tapes or conduits.
How Deep Should an Electrical Cable Be Buried in Australia?
Here’s the short answer:
Electrical cables should be buried at a minimum depth of 600mm (60cm) underground when installed directly into soil without conduit, according to the AS/NZS 3000:2018 Electrical Installations Standard (also known as the Wiring Rules).
But this isn’t a one-size-fits-all rule. The required depth depends on a few key factors:
Whether the cable is enclosed in conduit or laid directly in soil
If the cable is installed in a residential, commercial, or industrial setting
The type of soil or environment (e.g., dry ground, rocky terrain, concrete encased)
Whether the area is trafficked (e.g., driveways or pathways)
General Guidelines for Underground Cable Burial in Australia
| Cable Type | Minimum Burial Depth (in mm) |
|---|---|
| Direct-buried cable (no conduit) | 600 |
| Cable in heavy-duty conduit | 500 |
| Under paved/trafficable areas | 600–900 |
| Under concrete encasement | 100 |
| Within conduit inside a wall | As per AS/NZS 3000 layout |
Tip: We always recommend laying a warning marker tape 150mm above the cable path, especially in direct soil installations. This is required by law and helps prevent accidental strikes.
Does Cable Type Change the Depth Requirements?
Absolutely. Different cables are built to withstand different environments. Here are a few examples:
TPS cable (flat twin and earth): Usually not suitable for underground use unless enclosed in conduit
XLPE SWA cable (armoured cable): Designed for direct burial without conduit in many cases
Orange heavy-duty conduit: Commonly used in residential settings and allows slightly reduced burial depth
Not sure what type you’re using? Our qualified electricians will assess your site and recommend the safest, most compliant setup.
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Real-World Applications: Cable Depth in Common Situations
1. Running Power to a Shed or Granny Flat
Most backyard setups involve running power from the main switchboard out to a secondary structure. This involves:
Digging a 600mm trench (if using conduit)
Laying heavy-duty orange conduit
Pulling through compliant underground-rated cable
Laying warning tape
Backfilling and compacting
We offer full shed wiring services to keep your build compliant and future-proofed.
2. Driveways and Pathways
When crossing driveways or pathways, especially where there’s vehicle traffic, we recommend:
900mm depth minimum
Concrete encasement or rigid steel conduit for maximum protection
Compliance sign-off by a licensed electrician
This ensures your cable isn’t crushed or compromised from traffic movement.
3. Garden or Landscape Lighting
In lower-voltage applications (like 12V garden lighting), the rules are slightly different, but protection is still key. In most cases:
300mm to 500mm depth is acceptable for low-voltage
Cables still require conduit and tape for safety
Need outdoor lighting installed? We handle design, trenching, and installation for a seamless finish.
Check Out Our Outdoor Lighting Services
Can You DIY Underground Cable Installation?
Short answer: You shouldn’t.
While trenching may seem simple, only a licensed electrician can legally install or connect electrical cabling in Australia. The dangers of incorrect installation include:
Electrocution
Fire hazards
Voided insurance
Fines and penalties
When you hire Connex Electrical, we take care of all compliance, materials, and testing with zero shortcuts.
Book a Qualified Electrician Now
What If You Don’t Bury a Cable Deep Enough?
If a cable is buried too shallow, here’s what can go wrong:
It may be cut during future landscaping or digging
Exposure to UV, moisture, or animals may degrade the insulation
Your installation could be deemed non-compliant under AS/NZS 3000
You could fail an electrical inspection for property sale or council approval
💡 Best practice: Always get a trenching and cable plan signed off before installation. Our team provides this with every underground power job.
Cost of Underground Cable Installation
The cost varies depending on:
Length of trench
Site conditions (soil, rocks, access)
Cable type and length
Need for switchboard upgrades
Average cost for a small residential installation: $850 – $3,500
We provide detailed quotes, transparent pricing, and fast turnaround.
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With 15+ years of experience, we’ve handled thousands of compliant underground installations across Brisbane, Moreton Bay, and beyond. We know the AS/NZS 3000 rule book like the back of our hand.
When you choose Connex Electrical, you get:
- Licensed and insured electricians
- Underground cabling that exceeds safety standards
- Transparent communication and upfront pricing
- Clean-up and final testing included
- Service backed by workmanship warranty
We also offer full-service support for:
Final Word: How Deep Should Electrical Cable Be Buried?
To wrap it up:
600mm is the standard depth for direct soil installation
500mm is acceptable with heavy duty conduit
Deeper trenches are required under driveways and public areas
Always use warning tape and licensed electricians
The best way to stay compliant and safe? Let Connex Electrical handle the job from start to finish
Get a Free Underground Cabling Quote Today
Need underground power installed at your home or business?
📞 Call us today on 0474 207 609
📧 Or email us at [email protected]
We’re your local team of trusted electricians based in North Lakes, servicing Brisbane Northside, Moreton Bay, Redcliffe, and surrounding suburbs.