If you are like most people you have probably never stopped to wonder how the lights come on in your home. You press a switch, and the light comes on. As a certain meerkat is fond of saying, "Simples".

And it is.

You turn the tap on, and water comes out. Well that’s what you expect to happen, and it does. In fact, you would be pretty upset if you turned the tap on and water DIDN’T come out. Equally, you have a shower and not only does water arrive and wash you, but when it has done that it just simply drains away. The same thing happens when you flush the toilet. So what?

Here’s the thing: you never give a second’s consideration to HOW the electricity arrives at your home or how the shower water drains away. There is no reason why you should. However, it all has to come from somewhere so that you can use it, and when you have used some of it, it all has to go somewhere. Your electricity doesn’t come from a wire connected to your roof, and your shower water doesn’t drain away through a visible pipe either.

No. All these pipes and cables are hidden away underground where you can’t see them, and that is why you never give them a second’s thought.

However, if these things did not exist your life would be considerably worse. Just consider, for a moment, parts of Africa, where the only way to get water into the home is for people to walk several miles every day and carry it back in containers. Not a lot of fun.

But although we are lucky to have all these things literally "on tap", they can present serious problems for contractors who have to look after them, install them, repair them and so on. It can even cause problems for contractors who have absolutely nothing to do with the provision of these services but need to conduct excavations close to where the cables and pipelines all run.

For instance, a builder may need to work on construction of a property on a spare piece of land next to your home or business, but your water supply, telephone cables, electricity cables, gas pipes, sewage pipes, and so on, all run directly under that piece of land. You are going to be very unhappy if that builder digs down to build the foundations and disconnects any of them from your home by accidentally cutting through them.

This is why it is critical that the builder takes every precaution to ensure that he doesn’t do exactly that. Not only can he cut off your supplies, but it can also create severe danger to the workmen who are doing the actual digging. If they hit an electricity cable, gas pipe, water pipe, and so on, the workers can be severely injured. Indeed, there are around a dozen fatalities every year from exactly that cause.

This is why the builder or contractor must undertake a survey of the area before commencing any actual work. But how do you do that?

One way is to obtain the plans of all the utilities from the company which supplies them. This is a good starting point, but the builder needs to understand that these plans are not always accurate. However, the good news is that there are tools that he can use to locate and identify the various services and where they run, so that he can avoid hitting them. They are known as the CAT (Cable Avoidance Tool) and Genny (Signal Generator). Used in combination they can locate most underground services, although they do have certain limitations.

People who are skilled in using the CAT and Genny will have been trained in the way to use them and have achieved certain certificates to prove that they have the knowledge. There are several of these such as an EUSR certificate which will show that the holder has been trained in EUSR cable avoidance. The EUSR is the Energy and Utility Skills Register. There are others such as the CITB certificates, and the CSCS. Holders of these are allowed to work on contracts such as the HS2, and other construction sites where you cannot work if you do not have them.