Converting Overhead Power to Underground in Sydney: The Real Process, Approvals and Timeline

What does it actually take to convert overhead power to underground in Sydney? Four things: a route design, your distributor's approval, a trench with conduit to strict specifications, and a switchover day where a Level 2 ASP disconnects the old service and livens the new one. The digging is usually the quick part. The paperwork and coordination are what stretch the timeline into weeks.

⚡ Quick Answers: overhead to underground conversion

• Can any electrician do the conversion? No. Work on the service and consumer mains is restricted to accredited Level 2 ASPs, with the distributor controlling the network end.
• Do I need network approval? Yes. The connection change goes through your distributor, and the completed work is documented back to them by your ASP.
• Where does the new cable connect? Usually at the nearest existing network pole, running down the pole and underground to your property. This arrangement is called UGOH, underground from overhead mains.
• How deep does the cable go? SIRNSW requires the service cable in conduit at a minimum depth of 500 mm, with orange marker tape buried above it.
• Who maintains it afterwards? You supply and maintain the conduit on your land, and you wear access costs if the run is ever dug up for repair, which is why the route is worth designing properly the first time.

1. Designing the route

An underground service has rules an overhead span never worried about: the run is limited to 50 metres to the main switchboard, it wants a straight alignment with sweeping bends only, and it must dodge every other buried utility on the way. Before any design is final, the underground services search happens, which is why we wrote about how BYDA works and why sparkies never skip it. Driveways, mature trees and neighbouring services all shape where the trench can go.

2. The paperwork

Converting a connection type is a change your distributor approves, not just observes. Your Level 2 ASP handles the application and, on completion, lodges the Notification of Service Work with a sketch of the buried route. Ausgrid and Endeavour Energy run their own processes and timeframes, so the first practical step is knowing whose area you are in. You can check your network area in seconds with our postcode checker, and our comparison of connection timeframes across the two networks shows why the same job can move at different speeds a few suburbs apart.

3. The trench and the conduit

The buried run is built to SIRNSW specification: heavy duty conduit of at least 40 mm, laid straight at a minimum 500 mm depth, with orange marker tape above the conduit warning future diggers. Where the run crosses a driveway or the ground level fights the design, the detail work grows. This underground standard is a big part of why storm season barely touches underground services, a comparison we covered in ABC versus underground service, which also carries the cost discussion for both options.

4. Up the pole: how UGOH works

Unless your street already has underground mains, the new service still starts overhead. The cable runs from the nearest existing network pole, protected down the pole face, then underground to your property. No new street pole gets built for it, and each pole can only host a limited number of these underground runs before a footpath pillar is required at the customer's cost. That pole end detail is network territory and one of the clearest reasons the job sits with a Level 2 electrician.

5. Switchover day

With the conduit in, the cable proven and the paperwork ready, the changeover itself is typically a single day: planned disconnection of the overhead service, termination of the new underground run, testing, then reconnection. Our disconnect and reconnect service is built around exactly this kind of planned outage, and if the old service fed a private pole, its removal is scheduled in the same window. What happens at the pre connection inspection is covered in our post on the Level 2 site inspection before your connection is approved.

6. The timeline, honestly

The physical work usually fits inside two or three site days. End to end, allow weeks rather than days: distributor processing, the utilities search, trenching access and weather all sit on the critical path. Jobs slow down when the route crosses shared driveways or needs council road opening consent, and speed up when the trench line is clear private land. A conversion bundled into a renovation, while trenches are already open, is the cheapest version of this job, which is one of the nine electrical decisions that are far cheaper during a build.

Why it's Level 2 ASP work

The conversion touches the service line, the point of attachment and often the consumer mains, all of which sit beyond a standard electrical licence. An accredited ASP carries the authorisation to work at the network boundary, and the distributor holds the network side of the switchover. Our underground service mains installation service covers the full scope, with the overhead service mains service handling the disconnection side.

How High Demand Electrical helps

We run the whole conversion as one project: route design, BYDA search, distributor application, trenching coordination, cable installation, switchover and the closing paperwork. One team, one timeline, and no gap between the electrician who digs and the ASP who livens. If a private pole retires as part of the job, our private power pole team handles that too.

Overhead to underground FAQs (Sydney)

Does going underground remove my private power pole?

Often, yes. If the pole existed only to hold your service span and consumer mains, an underground conversion usually retires it, removing its ongoing maintenance obligations.

Can I dig the trench myself to save money?

Ask us first. An owner dug trench can work when it follows the approved route, depth and bedding requirements, but a trench in the wrong place or at the wrong depth costs more than it saves.

Will the power be off for long?

Normally one planned interruption on switchover day, measured in hours. Everything before that happens with your supply live on the old overhead service.

Does underground cost more than fixing my overhead service?

Usually yes upfront, which is why the comparison depends on what the overhead run needs and how you value storm resilience and appearance. Our ABC versus underground comparison works through it.

Get an underground conversion quote

Send us your address and a photo of the current service and we will map the realistic route, approvals and price. Get an underground service quote or call 0402 559 777. Scope and pricing are confirmed after a site assessment.