(The term earthing is commonly used in Europe, whereas grounding is more prevalent in USA)
Electricity can and will kill people unless it is controlled effectively. Even in seemingly low risk sites, management of electricity is the main determiner for human safety, not to mention preservation and protection of equipment and facilities. Of all areas earthing / grounding must be the primary concern, and demanding of competent, experienced operatives conversant with the latest industry standards. JMI harnesses the best equipment, the most sophisticated software and the expertise of its engineers to help clients create a safe environment.
What is earthing / grounding and why do we need it?

The most important cable in any electrical system is the earth cable, which directs fault currents safely away from the location by allowing it to dissipate into the strata of the earth. Electricity, be it in the form of a supply or lightning, is always seeking the most direct and easy path to ground and through astute planning, a site may dictate and provide that route. If a location does not have an adequate earthing/grounding provision it may lead to electricity finding alternate methods to ground, this is often through electrical equipment, but could easily be via human beings.

What We Can Offer

An earthing / grounding system is necessarily bespoke to a site and must be designed in accordance with the applicable industry standards. The designs which JMI produces are developed in a customer-focused manner to ensure that the most practical, safe solution is achieved. If requested by a client JMI can have that the design actualised and installed.

Soil Resistivity Survey

Designs usually begin with a detailed site survey, which requires JMI engineers to visit a site to carry out a range of tests. Soil resistivity tests can be undertaken using several methodologies, the most common, and often the most pragmatic, is the Wenner Method. Soil samples are frequently taken to establish the acidity of the ground, which informs the selection of the most suitable installation materials, thus extending the lifetime of the earthing/grounding system.

Once all site data has been collected a detailed design is constructed using the latest computer aided design software CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis). We provide a safe, cost effective solution that complies with all relevant standards and codes of practice.
A written report is provided detailing system layout, installation specification, soil resistivity and acidity levels, theoretical earth system resistance, ground potential rise, supporting graphs indicating touch, step and transferred voltage potentials in and around the site.

What is Touch Voltage?

If the installed earth/ground system of a site is poorly designed an electrical fault could turn any conductive materials into a lethal hazard. If a person is in physical contact with a part of the system, such as their hand, when a fault occurs it is vital that the system is robust enough to avoid death or significant injury. Transferred voltage is a special incident of touch voltage where voltage is carried into or out of a structure via a conductive material; an example of this may be fault voltage following service lines.

What is Step Voltage?

Step voltage is the term describing the electrical charge that a person might experience when standing one metre apart during a fault. Each leg can experience different surface potentials and result in their body becoming a conduit for the voltage.

The spectacle of lightning has inspired awe and fear as long as there has been life on this planet. Our fascination with lightning is akin to our fascination with potentially dangerous animals or activities.
The truth of the matter is that with the exception of floods (which affect entire populated areas in a single event) lightning is the biggest weather-linked killer. Whilst lightning may not threaten every day lightning protection is still essential; it only needs to strike once and it could kill the people who work in and around your premises and easily destroy everything your organization needs to operate, if your site is inadequately protected. Your people, building and content may be covered by insurance policies, but does it cover the consequential loss of staff, data or reputation?

JMI meets the demands in the new standard (BS EN 62305:2006) for thorough risk assessments by using a pragmatic approach, the latest software and knowledge of the best equipment and materials in the industry to convert potential hazards into protected zones. JMI can undertake such risk assessments on behalf of organizations.

What is Lightning

Lightning is a release of static electricity in the atmosphere, usually noted during severe storms of rain or dust, and often during volcanic activity. Lightning can form through either convection events (which is more common in large land masses such as USA and Africa) and frontal systems (which is more common in temperate climates such as UK).

A single strike of lightning can contain one hundred million volts of charge, can reach temperatures of approximately twenty-eight thousand degrees centigrade and exceed five miles in length as it searches for a route to earth. The enormous electrical force of a lightning strike generates secondary effects such as electro-magnetic pulse (EMP); the scale of which can damage electrical equipment and electrically stored data over a vast area.
Considering these facts it is unsurprising that the effects of lightning are often devastating.

Lightning Protection Systems Design

JMI Earthing is a specialist leading provider of system designs in lightning protection. JMI usually work from the architectural drawings of the site requiring a system. After evaluating any existing systems for compliance with the applicable industrial standards the JMI technical department produce full architectural drawings and schematics indicating a suitable, practical solution.
All drawings are produced in the latest edition of AutoCAD and come accompanied with a design specification and a bill of materials.

Often sought to protect against the corrosive effects of stray fault current and can be found on projects such as pipelines, harbour areas, rail applications or proprietary structures, cathodic protection utilises sacrificial anodes to intercept stray current before it can corrode or damage assets. JMI has a legacy of delivering innovative, longer life cathodic protection systems using EnvirAnode™ technology.

What are stray currents and how can we manage them?

If the installation of DC rail systems (including trams) is of a poor quality, stray current occurs from rails and traction systems in an uncontrolled and inevitably costly manner. Currents in the ground will search for paths of least resistance in the same way that lightning does, usually through structures and underground services. The consequence of such activity is corrosion, and then replacement.

From the inception of such rail projects JMI engineers are trained to identify potential problem areas and apply an effective solution prior to lying of the track slab. JMI’s stray current control solutions along with correct earthing and bonding designs save time and money.