How Deep Does Your Private Power Pole Actually Need to Go in the Ground?

How deep does a private power pole actually need to go into the ground? It depends on the pole's height above ground and the quality of the soil it is set in, and the standard range runs from about one metre in good, well compacted ground up to nearly two metres in poor, soft soil. Getting this wrong is one of the most common reasons a pole leans or shifts years after it was installed, long before anyone notices a problem above ground.

⚡ Quick Answers: Private Power Pole Sinking Depth

• Does every pole go in at the same depth? No. The required depth depends on how tall the pole stands above ground and whether the soil around it is classed as poor, medium or good.
• What are the three soil categories? Poor soil is soft clay or poorly compacted sand, medium soil is compact clay or bonded sandy loam, and good soil is well compacted rock soil or hard clay with good drainage.
• Does setting a pole in concrete change the depth? Yes. Concrete improves the effective soil quality by one step, which can reduce how deep the pole needs to be sunk.
• What if the pole is going into solid rock? The required sinking depth can be reduced by 0.3 metres when the pole is set into solid rock.
• Can a pole still be installed if the standard depth is not achievable? Yes, but only with an engineer certified alternative such as a flange mounted base, arranged before construction begins.
• Why does this matter years after the pole goes in? A pole set too shallow for its soil type is far more likely to lean or shift over time, and it is one of the most common findings behind a leaning pole call out.

1. Why pole depth is not a single fixed number

A private power pole is not just planted to an arbitrary depth and left at that. Under SIRNSW Clause 3.7.2.3, posts and poles must be securely set in the ground, and the depth required scales with two things: the free length of the pole from ground level up to the lowest conductor support, and the quality of the soil the pole sits in. A short pole in good soil might only need to go in about a metre. A taller pole in poor soil can need close to double that.

This is why a proper installation always starts with an assessment of the actual site, not a one size fits all footing. The free length above ground typically ranges from around three metres for a modest domestic connection up to over seven metres where extra clearance is needed, and the required depth increases in steps as that height grows.

2. The three soil categories that decide your depth

The rules recognise three soil categories, and each one changes how deep the pole has to go.

Poor soil is soft clay, poorly compacted sand, or any soil that tends to absorb large amounts of water. This is common on reclaimed or low lying blocks across Sydney and needs the deepest footing of the three categories.

Medium soil is compact clay, well bonded sandy loam, or bonded sand and gravel with reasonable surface drainage. Much of Sydney's established residential land falls somewhere in this band.

Good soil is well compacted rock soil, hard clay, or well bonded sand and gravel with good surface drainage. Sandstone adjacent blocks in parts of Sydney's north and west often sit closer to this category, though it should never be assumed without checking.

The only way to know which category applies to your property is to have someone assess the soil on site. Assuming a category without checking is exactly how a pole ends up set too shallow.

3. Typical sinking depths run from about one to two metres

As a rough guide, a shorter pole with a free length of around three to four metres needs roughly one metre in good soil, 1.3 metres in medium soil and 1.6 metres in poor soil. A taller pole with a free length around six to seven metres needs roughly 1.3 metres in good soil, 1.6 metres in medium soil and close to 1.9 metres in poor soil. These figures come from the standard sinking depth tables used across both SIRNSW and AS/NZS 3000, and they assume the pole is simply driven or placed into undisturbed soil without extra support.

If your property has a taller pole, carries a heavier service, or sits in soil that drains poorly after rain, expect to be closer to the deeper end of that range rather than the shallow end.

4. Setting a pole in concrete changes the equation

Many installers set a pole's base in concrete rather than relying on compacted soil alone, and this genuinely changes the depth calculation. Concrete is treated as improving the effective soil quality by one full step, so a pole in otherwise poor soil can be sunk to medium soil depth once it is properly concreted in, and a pole in medium soil can be treated as good soil.

There are specific details that matter here: the bore hole needs to be centred and sized at the pole's diameter plus around 100 millimetres, a timber pole's concrete should finish at least 250 millimetres below ground level, and a steel pole's concrete should finish about 100 millimetres above ground and be shaped to shed water rather than pool around the base. The concrete also needs to be left undisturbed for around three days, or long enough to properly cure, before the overhead line is attached and put under tension.

5. What changes if the pole is going into solid rock

Solid rock behaves differently to soil, and the rules account for that. Where a pole is set into solid rock, the required sinking depth can be reduced by 0.3 metres compared to the standard table figures. This reflects the much higher load bearing capacity of rock compared to even well compacted soil, but it still needs to be confirmed on site rather than assumed from a neighbouring property or a general sense of the area's geology.

6. When the standard depth simply cannot be achieved

Sometimes a straightforward footing is not possible, for example where underground services, rock close to the surface in an unusual configuration, or site constraints prevent the pole being sunk to its full required depth. In these cases an alternative construction, such as flange mounting the pole base to a reinforced concrete structure, can be used instead. The important part is that this alternative must be certified by a structural engineer as meeting the strength and stability requirements before construction proceeds, not worked out on site after the fact.

This is also where a lot of older, informally installed private poles across Sydney run into trouble. A pole that was simply set into whatever depth was convenient decades ago, with no soil assessment and no engineering sign off where needed, is a common contributor to the leaning poles our team gets called out to inspect.

Why it's Level 2 ASP work

Assessing soil quality, selecting the right pole size and footing depth, and arranging structural engineer certification where a standard footing is not achievable, all sit squarely inside the scope of work a licensed Level 2 Accredited Service Provider carries out under SIRNSW and AS/NZS 3000. This is not a job for a general electrician or an unlicensed contractor, because getting it wrong does not usually show up as an obvious fault on day one. It shows up years later as a pole that has slowly leaned, as cracking or splitting near ground level, or as a defect notice from the network operator during a routine inspection.

When High Demand Power Poles Sydney installs a new private pole, or replaces one that has failed, our Level 2 ASP team assesses the actual soil at your property rather than assuming a category, sizes and sets the footing to the correct standard, and organises engineering certification on the rare occasions a standard footing cannot be used.

How High Demand Electrical Helps

High Demand Power Poles Sydney is one of Sydney's most trusted Level 2 ASPs for private power pole work, and footing design is something we treat as seriously as the pole itself. We are a licensed local team, not a call centre booking in subcontractors, and we service homes and small businesses across Greater Sydney with the same soil assessment and footing standard on every job, whether it is a straightforward residential power pole installation or a more complex replacement on a sloping or poorly drained block.

If your existing pole is showing early signs of movement, our team can carry out a proper pole inspection to check whether the original footing was ever adequate for the soil it sits in, well before a lean becomes a safety issue or a formal defect notice.

Private Power Pole Sinking Depth FAQs (Sydney)

How do I know what soil type my property has?

You generally cannot tell by eye, which is why a proper installation always starts with an on site assessment rather than a guess based on the suburb or a neighbour's experience. Our team checks the actual soil condition at your specific footing location before finalising the pole size and depth.

Does an existing leaning pole mean it was set at the wrong depth?

Not always, but an inadequate footing for the soil type is one of the most common underlying causes we find. See our guide on what to do about a leaning power pole for the full picture, including other causes such as timber rot at ground level.

Can I check my pole's footing myself?

Not safely or reliably. Soil assessment, footing depth and structural adequacy are all part of a proper private power pole inspection carried out by a licensed Level 2 ASP, not something that can be judged by looking at the pole above ground.

Does a composite or steel pole need a different depth to a timber pole?

The soil quality and height calculations work the same way across pole materials, though the specific tables for timber, steel and composite poles differ slightly in their exact figures. Your installer selects the right table for the pole type being used.

What happens if my soil changes after heavy rain or nearby construction?

Soil conditions can genuinely shift after sustained heavy rain, nearby excavation, or drainage changes on an adjoining property, and this is part of why older poles that were adequate when installed can start to show movement later. If you notice any lean or softness around the base of your pole after major rain or nearby works, it is worth getting it checked rather than waiting, particularly if you were affected by the kind of event covered in our storm damaged pole guide.

For background on how earthing and soil conditions interact more broadly, our sister site's guide to MEN earthing in older homes covers the switchboard side of the same underlying soil and earth resistance principles, and our main site has more on general Level 2 electrician services across Sydney.

Worried your private power pole was never set to the right depth for your soil? Get a Private Power Pole Quote from High Demand Power Poles Sydney, or call us on 0402 559 777. Every job starts with a proper site assessment, since the right footing depth and pole size can only be confirmed once we have seen your soil and your property in person.