Periodic inspection of portable earthing and short-circuiting devices
June 2015
Electrical Power & Protection
An important measure when working on electrical installations, according to the five safety rules of DIN VDE 0105 - 100, is the fourth rule: “Carry out earthing and short-circuiting”. This ensures that the installation is dead while work is carried out. However, every protection measure is only as safe as the tools that are used.
Reduced cable cross-sections of portable earthing and short-circuiting devices (EaS devices) resulting from copper corrosion and breakage of conductor strands, or increased resistances in the connections, may have fatal consequences when earthing and short-circuiting devices are subjected to short-circuit currents. Therefore, portable EaS devices must be tested prior to each use and at regular intervals. So far, only a visual inspection made economic sense. However, a new procedure is now available which provides reliable information on the condition of the portable EaS device based on static and dynamic measurements of the ohmic resistance.
Dehn Africa offers this improved test for portable EaS devices on the customers’ premises.
An earthing and short-circuiting device is tested in three steps and the resistance values are compared with theoretically and experimentally determined limit values. The first step is the visual inspection for visible signs of damage. A static test is performed in the second step, in which the absolute resistance value is measured at the stationary earthing and short-circuiting device. Step three includes the dynamic test, which notes the measurement of the relative change in resistance at the moving earthing and short-circuiting device. The measurement of the resistance change value (R) between the non-moving and the moving EaS device is a new approach which allows for the detection of local damage, such as breakage of conductor strands in the conductor cable. The new test setup consists of a special micro-ohmmeter, a rail structure and the relevant software. Practical testing has shown that numerous earthing and short-circuiting devices tested are invisibly damaged. This damage could not be found by means of visual inspection alone, thus illustrating the importance of using the new procedures to test used EaS devices at regular intervals.
Safety devices and equipment from Dehn are manufactured and tested in line with the requirements of applicable standards. In addition to maintenance tests on earthing and short-circuiting devices, Dehn is also a reliable partner for maintenance tests on voltage detectors, switching sticks, fuse tongs, insulating sticks and earthing sticks.
For more information contact Alexis Barwise, Dehn Africa, +27 (0)11 704 1487, [email protected], www.dehn-africa.com
Further reading:
Schneider Electric accelerates adoption of SF6-free switchgear
Schneider Electric South Africa
Electrical Power & Protection
Schneider Electric is driving the transition to sustainable medium-voltage solutions across East Africa with its award-winning SM AirSeT pure-air switchgear.
Read more...
Critical power distribution for modern infrastructure
Electrical Power & Protection
Legrand has expanded its critical power portfolio with integrated solutions designed for reliable, efficient, safe and flexible power distribution in many applications, including data centres and industrial sites.
Read more...
How to use a voltage tester
Comtest
Electrical Power & Protection
Voltage testers are valuable tools for professionals who work with electrical systems.This application note will guide you on how to use a voltage tester effectively, and which Fluke voltage testers can assist in a variety of settings.
Read more...
Film capacitors for noise suppression
Electrical Power & Protection
Würth Elektronik has expanded its portfolio of components for the mains input. The new series of WCAP-FTY2 film capacitors is optimised for use in noise suppression and complies with X1 or Y2 safety classes in accordance with IEC 60384-14.
Read more...
Emissions pressures are not just hot air
Electrical Power & Protection
Dennis Williams, commercial director of AES says that the South African government aims to push towards global standards in emissions, but it might be difficult for our industries to carry the financial burden. This is where AES fits in.
Read more...
ABB achieves zero operational emissions
ABB South Africa
Electrical Power & Protection
ABB’s factory in Oiartzun, Spain, has reached a major sustainability milestone.
Read more...
Supporting the AI boom with power architecture
Electrical Power & Protection
Hitachi Energy is supporting the 800 VDC power architecture announced by Nvidia, by developing a cleaner, more efficient way to power the next generation of AI infrastructure.
Read more...
Terminal blocks with Push-X technology for wiring from 0,34 mm2
Phoenix Contact
Electrical Power & Protection
The Push-X product range is growing. With the new XT 1,5 terminal blocks, Phoenix Contact is extending the series to include versions for conductor cross-sections from
0,34 to 2,5 mm2.
Read more...
Energy cannot be destroyed, it can only be transferred
Schneider Electric South Africa
Electrical Power & Protection
Industry produces significant amounts of waste. Unfortunately, a lot of this waste is simply disposed of, usually impacting the environment. What if these byproducts could be transformed into a source of energy?
Read more...
Dual head safety pull switches with expanded cable span
Electrical Power & Protection
Referro Systems has added the latest Dual Head range of Allen-Bradley’s safety pull switches to its portfolio. It is ideal for protecting long stretches of equipment where quick access to a safety pull switch and emergency stop is vital.
Read more...
printer friendly version