Page 285 - Electrical Safety of Low Voltage Systems

as an electrical system, 72–76
cells, electrical nature of, 72–73, 72f
current, effects of, 76–77, 76f
current paths and, 86–87, 87f
direct currents, effect of, 90–93, 91f, 92f
impedance of, 84–86, 85f, 86f
permissible prospective touch voltage, 87–90, 87f, 88t, 89f

I
IMD. See Insulation monitoring device
Impedance bridge, 278–279, 279f
Independent earth electrodes, 51–55, 52f, 53f
Indirect contact, 2, 18–26, 32–33
Induced overvoltage, 210–212, 211f
Insulation monitoring device (IMD), 158–159, 158f
Insulation resistance test, 240–242, 241f, 241t, 242f
Interacting earth electrodes, 51–55, 52f, 53f
Internal voltage, 201
International Protection Code, 11, 12f
IT grounding system, 3, 3f
definition of, 155
direct contact protection
RCDs and, 163–164
equipotential bonding, 159
fault resistance in, 167–169, 168f, 169f
fundamental measurements in, 238–239, 239f
indirect contact protection
ECPs earthed collectively, 165–167, 165f, 166f, 167f
ECPs earthed individually, 164–165
RCDs and, 163–164
second fault to ground, 164–167
insulation monitoring device, 158–159, 158f
neutral potential rise, 160
overvoltage and, 159–161, 159f