Earthing system IT - Earthing system in which the neutral is isolated from the earth or connected to the earth via a high impedance and the various exposed conductive parts are connected to the earth via individual earthing circuits. An alarm must signal the appearance of a first insulation fault. The installation must be de-energized immediately in the event of a second insulation fault.
Depth of Discharge - The ratio of the quantity of electricity (usually in ampere-hours) removed from a battery to its rated capacity.
Separator - An ionic permeable electronically nonconductive spacer or material which prevents electronic contact between electrodes of opposite polarity in the same cell.
E-Rate - Discharge or charge power, in watts, expressed as a multiple of the rated capacity of a cell or battery which is expressed in watt-hours. For example, the E/10 rate for a cell or battery rated at 17.3 watt-hours is 1.73 watts. (This is similar to the method for calculating C-Rate.)
UPS (parallel without redundancy) - A UPS made up of several (n) parallel-connected UPS units with equal output ratings (P) and each equipped with its battery, for large loads. The total output is equal to the number of units multiplied by their individual output (n x P). In this configuration, no UPS unit is redundant.
Earthing system - System for the interconnection and earthing of exposed conductive parts and neutral. There are three types of neutral system - IT, TN, TT.
Drain - The current withdrawn from a battery during discharge.
