Locating and tracing underground pipes and cables

Before any excavation, repair or construction work, it matters that you know what is under the ground and where it runs. Unmarked water pipes, drains, electrical cables and communications lines can lead to damage, loss of service, unplanned costs and a real risk to the people on site.

ProKanal offers professional locating and tracing of underground pipes and cables, establishing the route of buried services without needlessly digging up large areas.

The service suits both a survey carried out ahead of excavation and the case where no reliable information exists about where the existing underground infrastructure runs.

What locating underground pipes and cables involves

Locating is a survey of the ground carried out to establish the position and direction of buried services.

Depending on the type of infrastructure and the conditions on site, the following can be traced:

• water mains and supply pipes;
• drainage and sewer pipes;
• metal pipelines;
• electrical cables;
• telecommunications and signalling cables;
• street-lighting cables;
• underground runs between buildings and structures;
• certain non-metallic pipes and ducts, where conditions allow a suitable tracing method.

Once located, the route can be marked out on the ground, so that everyone knows where the buried service runs before work starts.

Why locate buried services before you dig?

Even where old plans or records exist, the actual position of pipes and cables does not always match what those records show.

Locating buried services beforehand helps reduce the risk of:

• cutting or damaging an electrical cable;
• bursting a water pipe;
• damaging a drain;
• cutting a telecommunications line;
• incidents and unplanned repair costs;
• delays to construction work;
• digging up ground that need not have been disturbed.

Locating is therefore particularly advisable before excavation, drilling, boring, fencing, foundation work, landscaping and anything else that breaks ground.

How pipes and cables are found underground

The method depends on the type of service being sought, its material, the access available and the conditions on the particular site.

For conductive metal pipes and cables, electromagnetic locating can be used. A specialist transmitter applies or induces a signal onto the line, and a receiver at the surface allows that signal to be followed along its route.

Where a direct connection is not possible, the signal can be applied by induction if conditions allow.

For certain non-metallic pipes, ducts and drainage runs, sondes or tracing devices can be used: they are introduced into the pipe and then followed from the surface.

This makes it possible to establish the direction of a hidden run even when the pipe itself does not conduct.

Locating water and drainage pipes

Not sure where an old water or drainage pipe runs?

It is a common problem in older buildings, yards, industrial sites and properties with no up-to-date plans of the buried infrastructure.

Locating water and drainage pipes establishes their likely route and avoids digging blind.

On drainage systems, introducing a sonde or other tracing device can allow the pipe’s route to be followed from the surface. Where their internal condition also needs looking at, this is combined with a CCTV survey of pipes and drainage.

This is particularly useful for:

• an unknown drainage route;
• finding inspection points;
• planning a repair;
• preparing for excavation;
• building a new drainage connection;
• surveying existing water and drainage infrastructure.

Locating electrical and communications cables

Damaging a buried electrical cable during excavation can be dangerous and cause serious material loss.

Locating cables underground is therefore an important part of preparing the ground before excavation begins.

Where conditions allow, electrical, telecommunications, signalling and other conductive cable runs can all be traced.

Once the route is established it can be marked at the surface, which makes the work of construction and repair crews considerably easier.

When the service is needed

Tracing pipes and cables may be needed in a range of situations:

• before excavation begins;
• before work on a yard or surrounding ground;
• when putting up a fence;
• before drilling and boring;
• when laying a new water main or drain;
• when reconstructing existing infrastructure;
• where no plans of the buried services exist;
• where the old plans are not reliable enough;
• when looking for an unknown water or drainage run;
• when looking for a buried electrical cable;
• before construction or landscaping;
• when preparing to deal with a burst or fault.

Tracing without needless digging

One of the main advantages of professional locating is that a non-invasive survey from the surface can be done first, instead of starting to dig straight away.

Where the route can be located reliably, excavation can then be directed at one specific area.

That saves time and money, and limits damage to paving, yards, planted areas and the rest of the ground.

Can the depth of a pipe or cable be determined?

With certain methods and under suitable conditions, professional equipment can give an indicative depth for the located run.

The accuracy depends on a number of factors, though – the type of service, how the signal was applied, the proximity of other conductors, the characteristics of the ground and any interference.

For that reason a measured depth should be treated as part of the professional survey, not as grounds for uncontrolled mechanical digging right next to the run.

How locating and tracing proceeds

Work usually starts by establishing what type of service is being sought and roughly where it is thought to run.

A survey of the ground follows, along with the choice of a suitable locating method. Where a reliable signal is present, the route is followed at the surface and can be marked out on site.

On more complex sites, any available plans and records of the infrastructure also help in interpreting the results correctly.

The combination of prior information, professional equipment and an on-site survey gives a considerably better basis for planning the work that follows safely.

The advantages of professional tracing

Professionally locating pipes and cables underground can help with:

• carrying out excavation more safely;
• limiting the risk of damage and incidents;
• reducing needless digging;
• planning a repair more precisely;
• finding unknown runs;
• saving time spent searching for buried infrastructure;
• limiting unforeseen costs;
• preparing a construction or repair site properly.

Locating and tracing buried services with ProKanal

If you do not know where a pipe or cable runs underground, do not start with trial holes dug at random.

The ProKanal team can survey and locate the buried route with equipment suited to the particular case.

The service is used by homeowners and property owners as well as by companies, construction crews, building managers and organisations that need to establish where existing buried infrastructure runs.

Get in touch with ProKanal, describe what kind of pipe or cable you are looking for and where the site is, and we will judge the appropriate way to locate it.