Saturday, August 9, 2014

Insulating Mats

While everyone was absorbed in the landslide technological developments taking place in communication and protection fields of Electrical Engineering, a silent revolution has taken place in rubber mats laid in front of switchboards as a means of providing safety for operators from electric shock. Gone are the days when mats looked like foam beds! The new mats are so thin, that you would wonder whether they would fly off if you switch on a man-cooler. Yet, these ultra thin mats are so effective that the industry has switched over to them. What follows below is a comparison between the old and new mats and a synopsis of their characteristics.

New Mats conforming to IS 15652:2006 Old Mats conforming to IS 5424:1969
Made of synthetic elastomer Made of vulcanized rubber
Notified for use in India for all installations after Nov 1, 2007 through Gazette notification SO-2086 Superseded from Nov 1, 2007
High electrical insulation  resistance 10,00,000 mega ohm when measured with 500 V meggar Comparatively far lower insulation resistance
100%  shock  proof  under  leakage  current 10 mA Unsafe     in     case     of     leakage     of     current. Tested   from   small   electrodes   as   per   IS: 2584-1963 the value of the leakage current is 160 mA per sq. mtr.
Fire Retardant High fire prone & fire encouraging
No effect of
(a)  Transformer oil
(b) Acid
(c) Alkali
(d)  Diesel
  Affected by all these
The withstand voltage is 36kV  for one minute for 3mm mat The withstand voltage is 15 kV for one minute
High dielectric strength 65KV for 3mm mat Only 40 KV
Moisture proof Absorbs moisture
Pastable type permanent fixed smooth trolley movement Cannot be fixed permanently
Washable - Easy to clean Not possible to clean
High tensile & elongation properties to withstand good mechanical properties. No such properties as mat has to be removed for movement of trolleys

The voltage class and thickness of mats are as follows

New Mats conforming to IS 15652:2006 Old Mats conforming to IS 5424:1969
Thickness (mm) Voltage class (kV) Thickness (mm) Voltage class (kV)
2.0 3.3 not less than 6.5 mm not exceeding 3.3 kV
2.5 11
3.0 33
3.5 66