At Sygma Solutions we are acknowledged as one of the foremost providers of cable location training courses in the UK We believe that every site survey for underground services should begin with the Genny. Our Level 2 cable avoidance courses are designed for operatives who need to boost their skills and confidence and at the same time obtain a first-class level 2 qualification in cable avoidance and utility location (which is a requirement if you wish to work on HS2).

It is essential to obtain record information for all sites, whether they are historic records or statutory records. The more information that you have when attending a site helps you to evaluate the site and consider all the possibilities. If you don’t have any records and there is no signal, no access points, and no marker posts, and the service is buried, there is no way that you can know it is there. Records can help to identify anything that might actually be there.

We provide training on the RD8100 and the Mala Easy Locator. The RD8100 works on electromagnetic principles, while the Mala Easy Locator uses ground-penetrating radar. The RD8100 provides three methods of locating underground services, these being the passive method, induction method, and direct connection. It is used mainly for locating electric cables and metallic pipes.

Electricity cables and telecoms cables give off their own background signal which may be a power or radio signal, and in the passive mode, this can be detected at the ground surface. The signal does need to be strong enough. However, if the power is off – for instance, streetlights are switched off during daylight hours – there will be no signal. However, sometimes there can also be an issue with live cables if they are high voltage and of the “balanced” type which is designed specifically not to give out any signal. There can also be issues with some ductile iron pipes too because while they may be detectable at certain points, some of them have a rubber seal at the end of each section which has the effect of breaking the conductivity of the signal.

Using the RD8100, when you have surveyed the site in passive mode and are receiving no further signals, it is time to switch to the induction mode. What this does is to try to attach a generated signal on to underground service, the object being, once again, to trace the signal on the ground surface. The way this works is that the signal that is generated should attach itself to the service and then travel down the length of that service so that you can monitor it on the surface and plot where the service pipe, cable, or whatever, runs.

If this fails to produce any results, the next step is to physically attach the RD8100 to a utility at source using leads or a clamp. This can cause problems because you have to be able to access the utility at some point, which is often a cable riser, inspection chamber, stop valve, or plant room. That’s fine if you can locate it, but sometimes the access point is behind locked gates or outside the survey area. There is a limit to how far you can go looking for an access point away from the area.

This is where the Mala Easy Locator can be the answer. Ground Penetrating Radar won’t locate the services themselves, but instead finds differences in the density of the ground to locate possible sites. This is fine on flat land because the radar unit needs to be close to the ground. If the site is bumpy, overgrown with weeds, the soil is heavy or wet clay, has been backfilled with rubble, and so on, it can once again not operate.

All of this, and a whole lot more, is what we teach in our training courses at Sygma Solutions, and as you have seen from all the foregoing, there is a lot to understand and to take account of when you are undertaking these surveys. There can be a lot of pitfalls and things to take into consideration. In short, just because the equipment seems to register nothing is there, doesn’t mean that nothing is there!