SUPPLEMENT FEATURE CABLING & CABLE MANAGEMENT Fast, effective fault location for LV cables
Designed for use on underground LV cable networks, Megger’s new EZ-THUMP 3 cable fault location system makes it possible for users to accurately locate faults quickly and easily, thereby reducing the duration of power outages and the risk of costly penalties
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any low-voltage cable faults can be found using a time domain
reflectometer (TDR), such as the Megger TDR2050. The TDR acts like a cable radar, sending a pulse through the cable, then recording and timing the reflections from an impedance change, such as an open or short circuit, and calculating the distance to the fault. Unfortunately, a TDR will not see high-resistance faults, which are very common in underground cable networks, so there is a need for a complimentary, combined approach. The EZ-THUMP 3 provides this, locating cable faults by combining the TDR measurement with a surge generator to find high-resistance faults. It works by generating a low- impedance spark at the fault location that can be seen with the TDR. Unlike test sets designed
primarily for use on MV cables, the Megger EZ-THUMP 3 can deliver its full 500 J surge discharge at lower voltages, allowing it to locate difficult faults effectively with minimal risk of further damaging the cable. In addition to its dual-stage capacitor surge generator, the EZ-THUMP 3 incorporates a time domain reflectometer (TDR) that displays results on a high- brightness colour display that can be read easily, even in direct sunlight. The TDR can be used on its own for pre-locating low- impedance faults, and also with the surge generator for pre-locating high-impedance faults using the arc reflection method (ARM). For accurate pinpoint fault location, the EZ-THUMP 3 is used in conjunction
with an acoustic/electromagnetic receiver or a voltage gradient detector. The instrument supports cable sheath testing and sheath fault location using the step voltage method. Designed from the outset to be easy to
use, the EZ-THUMP 3 is controlled from a single rotary knob, and for normal operation it requires no setting up. Users simply make the test connections to the cable and switch the instrument on. After it has verified that the earthing arrangements are correct, using Megger’s renowned F-OHM safety method, the EZ-THUMP 3 automatically pre-locates the fault and displays the results both graphically and numerically. An expert operating mode is also
available, which allows experienced users to fine tune the operation of the instrument to optimise performance as an aid to locating especially
challenging faults. The internal rechargeable
battery used in the EZ-THUMP 3 has
been designed to offer a long service life. When a replacement eventually becomes necessary this can be carried out in the field by the user, meaning there is no need to return the instrument to the manufacturer for servicing. The EZ-THUMP 3 is suitable for use on street lighting, distribution and campus networks, and is small enough to transport in an ordinary car. It can be powered from either a normal AC mains supply or from its own internal rechargeable battery, making it suitable for use in almost any location, even where access is restricted.
Megger
megger.com
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bespoke cable management solution was delivered to a tight deadline ensuring halls of
residence at the University of Warwick were ready to welcome students in time for the new term. Marshall- Tufflex’s sleek Odyssey PVC-U trunking system is designed specifically with health, education and office environments in mind. Bespoke lengths of 2.25m were cut to size to fit-out student rooms in the Arthur Vick Residence at the university. The Odyssey trunking was supplied in white with flush fitting charcoal accessory boxes to comply with Part M of the Building Regulations. The dado trunking delivers data and electricity to desk areas in each of the 150 study rooms and was part of a refit of the whole residence. The halls are in constant use so the pressure was on to complete the refurbishment during the university vacation time. This specialist service offered by Marshall-Tufflex was a key consideration, but Odyssey was also chosen for its stylish curved profile, which has the added benefit of avoiding dust traps or cluttered surfaces and makes cleaning easy. Specially designed wrap-around covers give added security and result in smoother lines to further enhance Odyssey’s appearance. With a tight turnaround to get the project
completed, ease of installation was another key factor. As well as being cut to size off-site, the base is pre-punched so does not require drilling. The trunking has adjustable bends with a 25mm bend radius to manage difficult angles, and cabling is made easier thanks to a specially designed internal cable tray. The three compartments allow full cable segregation and both trunking and accompanying fittings are suitable for installations up to Cat 7a. The system is even tamper resistant thanks to fittings that locate with a special clip design.
www.marshall-tufflex.co.uk
BESPOKE TRUNKING SOLUTION PROVIDED TO UNI CAMPUS
S8 JUNE 2018 | CABLING & CABLE MANAGEMENT
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