One of the biggest problems that contractors face when carrying out any work below ground level is accidentally making contact with underground services. The simple fact is that underground services can exist anywhere, even in the most unlikely places. It is fairly obvious that they will exist in streets and roads with buildings, because we all need water, electricity, telecoms, and sewage pipes, and in some cases gas, and these services have to be provided to all buildings.

However, underground services may also be found in the middle of a field. You might ask why, and what they would be doing there, but it is always possible that cutting across a field is the shortest distance between two points and that is why the utility chose that route. It follows that before undertaking any sort of excavation or digging, the area to be worked on must be surveyed by a qualified operative in order to ascertain the location of any services and also to identify what they are as far as is possible.

The first thing to do, according to the HSE, is to plan the work. Then buried services must be located and identified, and finally the work must be carried out in a safe manner. Planning the work includes contacting all the relevant utilities in the area and obtaining copies of all plans that they have together with any other relevant information.

However, the plans must never be relied upon. Some of them are out of date. Others may never have been accurate in the first place. Furthermore, the data that plans contain can vary considerably in the way in which it was recorded, so one set of plans may appear to be very different from another from a utility in a different area, even if it is actually similar. There is simply no mandatory and unified recording system. Plans, or STATS as they are known, can only ever be used as a guideline, but they are a good starting point.

Plans may also not be accurate because a contractor putting in services may have cut corners and there is no way of knowing. For instance, a cable may have been laid at a shallower depth than was instructed, for the simple reason that it saved time digging down further. Once the cable is covered up, nobody is going to be any the wiser.

The most important thing to do, after plans have been considered, is to undertake a survey of the area to be worked in order to locate and identify any and all underground services and mark their location. However, that can present some big problems. For example, some tools can only locate metal pipes and not plastic ones. Others can only locate electricity cables when power is actually running through them. That means that if you carry out a survey when the streetlights are on you will locate the cable, but if you do it in daylight when the streetlights are off, you won’t. The cable is still there, however.

Then there are other problems. A cable may be present but be encased in a layer of concrete, so may be difficult to locate or identify. On top of that, the tools used for the purpose of location may only be able to read to a certain depth, so if a cable is – say – more than three feet down, the locator won’t show that there is anything there. Now there is a very simple technique to deal with that problem and it is one of the many reasons why proper training of the sort that we provide at Sygma Solutions is vital for all operatives undertaking cable avoidance work.

The answer to that problem is that you use the CAT and Genny to locate underground services and if there is nothing showing you then start to dig very cautiously, perhaps down to about a foot. You then carry out ANOTHER survey over the same area that you have just dug, and this time the cable may show up. Even so, you cannot just assume that there is nothing there and carry on digging. Unfortunately, some contractors do, and that is why there are some 60,000 cable strikes in the UK every year. You need to dig down further and repeat the survey.

This is just one of the things that we teach in our training at Sygma Solutions. It is far better to proceed slowly than just assume that nothing is present: it may take a little longer, but the old saying is that it is better to be safe than sorry.