Specialist Technical Services at Earthing Services: A summary

Kurt Robey & Jake Jones, Earthing Services engineers

Kurt Robey & Jake Jones, Earthing Services engineers

Earthing Services offer quite a few technical services in electrical safety systems so the first time that you experience the company it may seem baffling. This is not an organisation seeking to blind its customers with science, or bamboozle clients with empty phrases, Earthing Services wants to help interested parties navigate its service provision and product portfolio as clearly and as easily as possible.

Electrical safety systems such as electrical earthing / grounding or lightning protection systems have often been undervalued due to a legacy mindset in the construction industry, and sadly a few backward looking, low-tech, installers perpetuate this due to a lack of knowledge and a determination to avoid best practice.

Fortunately Earthing Services is able to support its client base with practical answers and expert knowledge. If you are not sure of the exact service that you require, but know that you have a problem that needs solving then please get in touch by calling the office, or by submitting an email via the contact page. Rest assured, with Earthing Services you are in safe hands.

What follows on this page is a very brief overview of the variety of services on offer, but in all instances please refer to the dedicated page for each service:

 

Electrical Earthing / Grounding Systems:

In the event of fault electrical current being transmitted to a site, facility, or piece of infrastructure, these systems are expected to manage fault electrical current. The usefulness of them is dependent upon their capacity to safely discharge electrical current. The best way to ensure that an effective, safe, and robust electrical earthing system is specified is to contact the Earthing Services Technical Department and find out how the team can help. As we often say, the most important part of any electrical system is the earth, because that is the part that will keep you, and those around you, alive.

 

Soil Resistivity Surveys:

This service helps determine how the ground will be able to dissipate electrical current, which will ultimately dictate the attributes of the system required to safely manage fault current. The process of undertaking a soil resistivity survey involves Earthing Services engineers travelling to site where they will use testing instrumentation, such as the Megger DET 2/2, in combination with proprietary testing leads to take measurements of electrical resistivity performance. The measurements are taken at a range of distances, and sometimes in a range of areas. The data set is then processed through CDEGS software, which takes us happily on to…

 

Soil Modelling and Analysis:

A soil model, or sometimes referred to as a ground profile, is obtained by processing soil resistivity testing data (see above or on the dedicated service page for soil resistivity surveys) through industry leading CDEGS software, which enables Earthing Services engineers to assess the ways in which the mass of earth in the survey area will disperse electrical current. Whilst Earthing Services can only underwrite the veracity of input data that its own engineers have acquired, the company is able to process and analyse soil resistivity survey data that has been supplied by others, and this service is often used by companies without the same software capacity as Earthing Services. Soil models will define the number of layers there are in the earth within the given survey depth, and how each respective layer behaves when electrical current is introduced. This analysis, when combined with performance requirements, national standards and codes of practice will enable the development of an electrical earth system design.

 

Electrical Earthing / Grounding System Design:

Electrical earthing / grounding systems should be designed by trained engineers who have the ability to specify what variety and configuration of components will be required to achieve the performance criteria governed by client requirements, codes of practice, and standards. The CDEGS software packages used to develop electrical earthing designs enable our engineers to simulate a range of fault electrical current conditions and as such theoretically test the safety system before it is installed. Earthing Services engineers are focused on developing the most practical, time saving, and financially economical electrical earthing system to ensure that their clients achieve the best value system possible.

 

Touch potential Calculations:

Electrical potential differences are variances between spaces where electricity will discharge in a non-uniform manner. The difference in the electrical potentials in a given area can present safety threats and as a result form fundamental performance criteria in electrical earthing systems. “Touch potential” is a way of measuring the threat to life if someone is in contact with a structure during an electrical fault. Codes of practice and standards prescribe tolerable exposure levels for “touch potential” and Earthing Services engineers can assess whether a given area meets performance guidelines. As with each of these services, please feel free to refer to the service specific page for more information, or contact a member of our team.

 

Step Potential Calculations:

Step potentials share their concept with touch potentials, only in this instance instead of measuring the prospective electrical potential difference when physically touching a structure during a fault, it instead defines the difference in electrical potentials between someone’s feet. As electricity disperses into the earth the volume and intensity degrades and as such so does its apparent threat to life. The rate of notional decay relates to the ground’s resistance to electrical current. Even over very short distances, such as that between the feet of a person, electricity could degrade considerably, and the quantity of degradation will determine the apparent threat to life. An example of the previous point may suggest that between a person’s legs voltage may drop by 750V and that voltage could feasibly travel through a person if they provide the path of least electrical resistance. As you can imagine this determination is critically important; Earthing Services engineers are clear on the parameters and that’s why customers request this service of the company every day.

 

Fault Current Distribution Analysis and Modelling:

The capacity to predict how fault electrical current will behave is essential when working on any construction project as this means that one of the most dangerous anomalies that faces it can be safely managed. Earthing Services has experienced engineers working on industry leading software CDEGS to determine how fault current may behave and from these analyses pictorial graphs can be produced to evidence the results.

 

Rise of Earth Potential Studies – ROEP, EPR, or GPR:

We all work and live in places which depend upon the National Grid for the supply of electricity. The way that the National Grid transmits this electrical energy is through a network of transmission towers, power lines, substations and switch yards. In the event that there is a fault electrical surge in that network it is quite possible that the fault electrical current is going to cause problems until it discharges into the ground. When fault current hits an electrical earthing system the earth system’s inherent electrical resistance will result in a calculable voltage difference which then radiates into the system and surrounding mass of earth. If the system’s performance results in a high Earth Potential Rise (EPR) / Rise of Earth Potential (ROEP) /Ground Potential Rise (GPR) then the consequences could be disastrous and that’s why numerous customers find their way to Earthing Services’s respected technical team.

 

Electrical Earthing System Testing:

This service should be undertaken upon installation completion, at times of system modification, or periodically to assess ongoing performance of electrical earthing systems. Earthing Services has the capacity to test substantial power stations, solar farm installations, substations, and many other varieties of electrical earthing systems and the company’s engineers are often found certifying systems. Frequently the Earthing Services Technical team is contacted to undertake services starting at soil resisitivity surveys, and then go on to undertake design, all manner of electrical safety calculations and assessments as detailed above, and stay involved after the installation team have completed their works to test and commission the site.

 

Interference Studies – Electromagnetic Compatibility (EMC):

Electromagnetic interference is the result two competing sources of electromagnetic energy and usually results in unintentional and unwanted consequences. Examples of sources of electromagnetism are standby generators, radio transmitters, HV switch or LV switch, uninterrupted power sources and many others including light and heavy rail systems. The consequences of electromagnetic interference can see a destabilisation in operating systems, a clear example may be a rail network adjacent a hospital which may see rail activity jeopardise the effectiveness of life saving equipment. As there are regulations relating to EMC it is imperative that this aspect of a project is considered.

 

Stray Current Corrosion Management:

Stray current is a reference to Direct Current (DC) that has entered the ground unintentionally and this can result in corrosion of metalwork. Stray current corrosion is the effect that the stray DC has on metalwork, which is potentially severe corrosion and deterioration. As stray current is a problem that manifests below the surface of the ground it is unseen and difficult to detect. The most common causes of stray current are light rail systems, such as trams, or underground rail systems, such as the London Underground (Tube) or the Paris Metro. The varieties of metalwork most commonly affected by stray current are metal pipes, structural reinforcing, bridges, and cables. When problems cannot be seen due to being under the ground it is likely that the first time of recognition is at the point of a substantial collapse or failure in a network and as such it is vital that appropriate management of stray current occurs before these manifest. Earthing Services offers a number of services associated with stray current management and these offer a practical method to prevent stray currents from occurring, and to detect potential failure points before they cause significant problems.

 

Stray Current System Design:

The best way to address the problems associated with stray current is to prevent them from manifesting in the first place. A robust stray current management system will be designed specifically to manage the threat. Often stray current collector (SCC) systems incorporate reinforcing bar mats interconnected to a stray current collector cable (SCCC), along with traction bonding and a robust testing regime, which must be observed and rigorously maintained throughout the construction or remedial works phase of a light or heavy rail system. Earthing Services engineers have been appointed to provide stray current management designs and strategies on a range of high profile rail projects including Manchester Metrolink, Birmingham Metro, Nottingham NET, Dublin LUAS, London Underground and a number of others.

 

Stray Current System Testing:

As stated above proactive stray current management is the best approach, and this necessitates exhaustively testing system elements throughout all stages of construction. Ensuring that design parameters are achieved before commissioning testing at project completion invariably saves projects considerable sums of money. There are many simple “good housekeeping” types of activities that can be prescribed and by following them stray current escape opportunities will be negated. Regularly checking that base plates are electrically isolated from the running rail, undertaking rail to earth readings to ensure conformance with project requirements, along with ascertaining that electrical continuity throughout the running rails complies with the build specification will go a long way to detect problems long in advance of a concrete pour.

 

Audits, Testing and Commissioning:

Electrical earthing systems are often regarded as grim necessity that is usually not well understood and frequently undervalued. The capacity to walk onto a site and determine how effective the electrical earthing provision is, or indeed, to identify problems that others cannot determine is an attribute for which Earthing Services engineers are regularly praised. It is not uncommon for other sector companies to subcontract or hand on projects which surpass their own capacity, or expertise. As a result of Earthing Services undertaking problem solving, electrical earthing investigation, and site survey activities the company has saved its customers many tens of thousands of pounds by locating problems that others have missed. That being said, the best way to address any electrical earthing issue is to obtain the expertise at the right side of a project, being the start, and by doing so availing themselves of Earthing Services’s respected team. Earthing Services engineers regularly audit construction works to ensure that every opportunity has been actualised to improve electrical earthing performance and this can include testing a system at appropriate intervals. Once a system is in place, whether new or after many years it is prudent to regularly check that it meets with requirements and Earthing Services engineers can certainly help with that. Earthing Services is most regularly requested to commission installed electrical earthing systems when the company has designed them, however the organisation is occasionally brought in to substantiate the claims of other organisations. As with all of these services, please feel free to further explore them on their own dedicated page of this website, or get in touch with us through the contact page or by contacting the office.