When carrying out any sort of excavation work, accidentally hitting underground services can have a massive impact on the workers involved. It is estimated that there are some 60,000 cable strikes every year, but the exact number will never be known because some of them go unreported for a variety for reasons. Not the least of them is that the contractor involved may try to avoid paying compensation or fines for carelessness. Striking underground cables can also reflect on the competence of the contractor and thus reduce the prospect of future work.

According to the data, it is estimated that some 4 million excavations take place across the country every year, but in fact only 2.25 million of them are prefaced with a thorough search for underground services before the work began. That means that 44% of work takes place without a detailed look at the likelihood of underground services being present.

Major utilities that carry out excavation are telecoms companies, which account for about 35% of all excavations, and these are closely followed by water companies with 23%. These figures are taken from the LSBUD records of the number of searches on its website being carried out each year. However, only about half of all underground utilities have records on the site, although the number is growing.

There is another very big issue here and that is that different utilities record their plans and drawings in different ways. On top of that, over the years the drawings and plans have mutated through different levels from paper plans to everything being online today. Another issue is that many of the plans are inaccurate and may be out of date, and in other cases there are simply no records for one reason or another. What this means is that any plans, or STATS, as they are called, can only ever be used as a guide, so it is essential to carry out a thorough physical survey of the site before beginning work.

Carrying out a physical survey involves the use of the CAT and Genny, and the survey needs to be conducted by trained and qualified operatives because there is a lot to understand about how the CAT and Genny work in combination.

The Level 3 Certificate in Utility Mapping and Surveying is the qualification to undertake Pas128 Quality Level D (Desktop Survey) & Quality Level C (Site Reconnaissance Survey). As a Proqual QCF Level 3 Utility Surveyor you will also be entitled to obtain the gold CSCS Card, which is a requirement for working on many sites. It is not a legal necessity, but many contractors require people to hold it before they are allowed to work on their sites.

Our CAT and Genny training will teach operatives everything that they need to know about the location of underground services, and critically will enable them to understand that, good as these pieces of equipment are, they do have certain limitations. For instance, the depth of a buried service is one possible limitation. You could get a reading which suggests there is nothing there when there is. So the answer is to dig down carefully for a foot or so and then take another reading, and this time you could get a positive answer.

Most electricity cables will emit a power or radio signal which can be detected at the surface if strong enough by equipment such as the RadioDetection RD8000 in passive mode. However, if it is something such as street lighting which is not working as it is daylight, there will be no signal. Another issue is some of the high voltage cables which are the “balanced” type, and which are designed so that they do not emit any signal. Certain ductile iron pipes can also be difficult to detect if they have a rubber seal at each end of a section, which effectively breaks the conductivity of the trace signal and means that only certain sections of the pipe may be traceable.

Those are just a couple of the issues which can surround the location of underground services, and this is why the courses that we provide at Sygma Solutions are so valuable. We teach operatives everything that they need to know in order to conduct a successful survey.