Jul,17

1 Nominal system voltage
Voltage by which a system is designated.
2 Highest and lowest voltages of a system (excluding transient or abnormal conditions)
2.1 Highest voltage of a system
The highest value of voltage which occurs under normal operating conditions at any time and at any point on the system.
It excludes voltage transients, such as those due to system switching, and temporary voltage variations.
2.2Lowest voltage of a system
The lowest value of voltage which occurs under normal operating conditions at any time andat any point on the system.
lt excludes voltage transients,such as those due to system switching, and temporary voltagevariations.
3Supply terminals Point of supply
The point where the distribution system of the electricity supply authority and the electricalsystem of the consumer are connected.
4supply voltage
The phase-to-phase or phase-to-neutral voltage at the supply terminals point of supply.5 supply voltage range
The voltage range at the supply terminals point of supply.6 Utilization voltage
The phase-to-phase or phase-to-neutral voltage at the outlets or at the terminals ofequipment.
7 Utilization voltage range
The voltage range at the outlets or at the terminals of equipment.Rated voltage (of equipment)
The voltage assigned generally by a manufacturer,for a specified operating condition of acomponent, device or equipment.
9Highest voltage for equipment
Highest voltage for which the equipment is specified regarding:a) the insulation;
b) other characteristics which may be referred to this highest voltage in the relevant
equipment recommendations.
The highest voltage for equipment is the maximum value of the “highest system voltage””highest voltage of the system” (see 2.1) for which the equipment may be used.
NOTES
1 The highest voltage for equipment is indicated for nominal system voltages higher than 1 ooo v only. lt is
understood that,particularly for certain nominal system voltages，norma operation of equipment cannot beensured up to this highest voltage for equipment,having regard to voltage-sensitive characteristics such aslosses of capacitors, magnetizing current of transformers, etc.
ln such cases，the relevant recommendations must specify the limit to which the normal operation of thisequipment can be ensured.
lt is understood that the equipment to be used in systems having nominal voltage not exceeding 1 000 v shouldbe specified with reference to the nominal system voltage only,both for operation and for insulation.
3Attention is drawn to the fact that in some equipment standards (for example， IEC 60335-1 and IEC 60071-1) the term “voltage range” has a different meaning.

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