How to Locate Buried Cables Before You Dig

A trench for a new shed feed, garden lighting or a drainage run can turn dangerous in seconds if it crosses an unknown cable. Knowing how to locate buried cables before you dig is not just good site practice - it protects people, prevents expensive outages and keeps your project moving without avoidable damage.

Underground services are rarely where people expect them to be. Older properties may have additions installed at different times, private cables may not follow the most direct route, and site plans can be incomplete or out of date. Treat every proposed excavation area as though a service could be present until it has been properly checked.

Start with the service information

Before machinery arrives, request underground asset information through Dial Before You Dig. This provides plans from participating utility owners for assets such as electricity, telecommunications, water, gas and sewer networks. It is the right first step for work at homes, businesses and development sites across the Coffs Coast and Mid North Coast.

Plans are a planning tool, not permission to excavate blindly. They show the approximate location of registered network infrastructure and can be based on records that have changed over time. A plan may not show privately owned cables serving a house, shed, pool, gate, pump or neighbouring structure.

Read the plans alongside the site, not from an office desk. Look for service entry points, meter boxes, pits, poles, overhead lines, switchboards, sheds and recent building work. If a cable has to get from one point to another, its likely route deserves careful investigation.

Understand what plans do not show

The cable supplying your house after the point of connection may be privately owned. The same applies to a submain running to a granny flat, workshop or detached garage. These are common on rural and semi-rural properties, where power may travel significant distances underground to pumps, outbuildings, gates and amenities.

Private electrical work can be particularly difficult to trace because installation records are not always retained by later owners. The cable may also have been installed before current depth requirements or site practices applied. Never assume a shallow cable is redundant, or that a cable running in an unexpected direction is safe to cut.

Other unrecorded services can complicate the job too. Stormwater, irrigation, old water lines, communications cables and abandoned conduits can all appear in the excavation zone. Some may be inactive, but that needs to be verified rather than guessed.

How to locate buried cables on site

A proper location process combines records, visual inspection and physical verification. No single method is enough for every site.

Use a cable locator where conditions allow

A trained operator can use an electromagnetic cable locator to trace many underground electrical cables and conductive services. The equipment detects a signal emitted or applied to the cable, allowing the likely route to be marked on the ground.

This is useful, but it has limits. Signal strength can be affected by depth, soil conditions, nearby services, metallic fencing and electrical interference. Plastic conduit does not itself trace, and an inactive or disconnected cable may not produce a usable signal. A locator identifies a probable path, not an exact depth or a guarantee that no other service is present.

For this reason, markings should be treated as a guide for the next stage of investigation. Mark the route clearly and allow a sensible exclusion zone rather than placing an excavator bucket directly over a painted line.

Inspect the evidence already on the property

Walk the proposed route slowly. A meter box, switchboard, outdoor GPO, garden light, pool equipment, bore pump, air-conditioning unit or shed can reveal where a cable may begin or end. Look for changes in paving, narrow strips of newer lawn, conduits emerging from walls, old trench lines and utility marker posts.

Ask the owner, builder or previous contractor what has been installed and when. Photos from construction, electrical certificates, renovation plans and invoices can all help build a clearer picture. Useful information does not replace a physical check, but it can prevent a lot of unnecessary digging.

Expose services by hand or vacuum excavation

When the route is close to a known or suspected service, the safest way to confirm its position is to carefully expose it. This is often called potholing. Hand excavation with insulated, non-conductive tools may be suitable for a small, controlled area, provided the work method is appropriate for the identified hazards.

Vacuum excavation is often the better option where accuracy matters, multiple services are present or the ground is difficult. It removes soil with far less risk of striking a cable than a toothed bucket. Once exposed, the service can be visually identified and its depth and alignment confirmed before mechanical excavation continues nearby.

Do not use a pick, crowbar or powered digging tool to hunt for a suspected cable. A direct strike can damage insulation without immediately tripping a circuit, creating a serious hazard that may only appear later.

Plan the excavation around the confirmed route

Once a cable has been located, adjust the work plan where practical. Moving a trench route by a small distance can reduce risk, avoid unnecessary service protection and save time. On tight sites, sequence the work so services are exposed and protected before the excavator starts the main cut.

The final trench depth, separation from other services, conduit type, warning tape and cable protection all need to suit the job and relevant requirements. This is especially relevant for new electrical service runs. A cable that is safe when installed can become vulnerable if it is too shallow, unprotected, or mixed with other services without proper separation.

For electrical work, use a licensed electrician who understands underground installation as well as connection requirements. For excavation, use an operator who works to the service information and is prepared to slow down when site conditions do not match the plans. Coordinated electrical and earthworks capability means fewer handovers and clearer responsibility around the trench.

Stop immediately if you find an unknown cable

If you uncover a cable that was not expected, stop digging. Keep people, plant and tools clear of the area. Do not touch, move, pull or attempt to identify a cable by cutting it.

If a cable has been hit, assume it is live even if there is no visible damage or loss of power. Keep clear of the plant and surrounding ground, prevent others entering the area, and contact the relevant network operator or a licensed electrical contractor for advice. Where there is an immediate danger, such as arcing, smoke, fire or a fallen powerline, call emergency services.

A damaged cable can present a serious electric shock risk through the machine, the soil or nearby metalwork. The operator should follow safe emergency procedures rather than jumping down from plant if there is a potential energised contact.

Common mistakes that create expensive problems

The most common mistake is relying only on a utility plan. The next is assuming a cable will be installed at a consistent depth or run in a straight line. On established blocks, neither assumption is reliable.

Another issue is treating the first exposed service as the only one. Services are often grouped, crossed or installed at different depths. A trench may encounter power, communications and water within a short distance, particularly near buildings, driveways and service entries.

Rushing because the excavation is small is also risky. A short trench for a mailbox light or irrigation crossing can still damage a main supply cable. The size of the hole does not reduce the consequence of getting it wrong.

Get the right people involved early

If your project includes a new underground power run, shed connection, switchboard upgrade, driveway crossing or site cut, discuss the proposed route before excavation begins. A contractor who can assess both the electrical scope and the ground conditions can identify clashes early, organise locating and potholing where required, and build the trench correctly from the outset.

GROUND. provides licensed electrical and earthworks services across the Coffs Coast and surrounding Mid North Coast areas, helping clients coordinate underground services without the usual gap between trades. The aim is straightforward: safe digging, compliant installation and a finished site that is built to last.

The ground rarely tells you what is underneath it. Taking the time to locate, expose and protect buried cables before digging is the practical decision that keeps a routine job from becoming an emergency.