· High power probe resistor limits fault current
· GS38 is due to be updated
The British Standard relating to two-pole voltage indicators, BS EN61243-3 was revised in 2010 and came into force in May 2013. Now all voltage indicators on the British and European markets should comply with the latest version of the standard, which precludes the use of a fuse.
The new standard relates to the use of a fuse in two-pole voltage indicators as there is a technical argument that fuses in a voltage indicator can cause unreliability and any problem with the fuse could cause the voltage indicator not to indicate a hazardous voltage.
In reality this risk is very small according to Martindale and correct proving procedures will identify the problem. Nonetheless, because of this potential problem, BS EN61243-3 prohibits the use of fuses in two-pole voltage indicators. As part of its design, the Martindale VI-13700 has always included a fuse in the probe to limit the current in the event of damage to the cable.
In order to fully comply with BS EN61243-3:2010, Martindale has released an updated version of VI-13700/2 with a model number of VI-13800. This new model has the fuse replaced by a high power resistor in the probe that will limit the current in the event of damage to the cable.
This protection is superior to the protection offered by the fuse as the current that can flow under fault conditions is considerably less. Martindale claims that the vast majority of competitive products have no protection built into the probe.
The company says that HSE Guidance note GS38 has not been revised for many years and has therefore not kept pace with technology or international standards. It is due to be updated. The existing version of GS38 does not require fuses in a two-pole voltage indicator built to a recognised standard such as BS EN61243-3.
Apart from the fuse/resistor in the probe everything else about the specification of VI-13700/2 & VI-13800 is identical, including the contrasting inner cable sheath to quickly identify cable damage.
In order to distinguish VI-13700/2 from VI-13800 the new model has the probe changed to all black instead of yellow. The probe is clearly marked ‘impedance protected’ rather than showing a fuse rating. It is sealed and has no user replaceable parts.
For further information please visit PASS Ltd’s specialist voltage testers web page (http://www.tester.co.uk/