Every day in the UK there are over 12,000 street works taking place, virtually all of which involve digging to some depth, and some of these result in striking underground services of one sort or another.

The reasons for striking underground services can be many, but overall, the main reason is insufficient knowledge of the likelihood of services being present at a site before any work was commenced. This is partly due to there being little or no record of underground services at a site and partly due to lack of a thorough survey of the site before work began.

The Health and Safety Executive has produced guidance in HSG47 which is designed for all of those involved in commissioning, planning, managing, and carrying out work on or near underground services, as well as the owners and operators of those services.

The guidance is first and foremost to obtain service plans and drawings from utility companies and other organisations with information about the site. While this is an essential step it also contains a big stumbling block because the information available may be sketchy, or it may be inaccurate, or it may not even exist.

This is partly due to the fact that there is no overall method of recording information, and this means that different utilities will record the information in different ways. Some may keep drawings on paper, others on a microfiche, others in cloud-based storage, and so on. Furthermore, as the years have passed, utilities have upgraded their information from one storage method to another and errors may have crept in as a consequence.

The information may have been recorded wrongly to begin with. As an example, a contractor may have been required to install a cable or pipeline at a specific depth, but in order to save time, and therefore money, the said contractor has cut corners by failing to dig as deeply as ordered. So, the utility concerned may record the service as being at a depth of 4’ when in fact it is only at a depth of 2’.

That is just one example, but it shows why you can never rely totally on the records kept by a utility. It could be very dangerous to do so. Certainly, you should always obtain whatever records are available, but they should only ever be used as a guide.

Ultimately, You Must Carry Out A Survey

Ultimately, the only way to obtain information about which you can be more certain is to undertake a thorough survey of the area before commencing any work. Even then, excavation must be undertaken with caution. However, it is alarming that excavations are often carried out without a site survey beforehand. The reasons given for such an action can vary, but a common one is that the contractors did not think they would dig deep enough to hit anything! Another excuse is that they did not believe that it was their job to carry out a survey.

Every excavation site should have a thorough survey using the CAT and Genny for cable location before work commences. All operatives who are going to undertake such surveys need to go on a cable location course such as the ones that we provide at Sygma Solutions.

The courses that we provide are essential because undertaking a survey for underground services requires in-depth knowledge of how the CAT and Genny work in their different modes, and also a knowledge of the fact that they do have limitations, so it is essential to know what those limitations are.

A fairly straightforward limitation is depth. There is a limit to how deep the tools can read, so an untrained user might get a negative reading and think that there is no service there when in fact there is. The answer in that case is to commence to dig carefully, and then having dug down a foot take another reading. If there is a service there, this time it may show. If not, dig down another foot, and so on.

Our cable location course has been designed by our team which has over 100 years of combined experience, so by taking the course and passing the exam, operatives can be certain that they have as much knowledge as possible.