Gemini Instruction Manual I-GARD
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10-1102 use.
1 ) Neutral grounding devices shall be permitted to be used only on a system involving a true neutral
or an artificial neutral, where the line to neutral loads are not served.
2 ) Where a neutral grounding device is used on an electrical system operating above 5 kV, provision
shall be made to automatically de-energize the system on the detection of ground fault.
3 ) Where a neutral grounding device is used on an electrical system operating at 5 kV or less, provision
shall be made to automatically de-energize the system on the detection of ground fault, unless
a ) The ground fault current is controlled at 5 A or less; and
b ) A visual or audible alarm, or both, clearly identified to indicate the presence of a ground fault
is provided.
10-1104 neutral Grounding Devices.
1 ) Neutral grounding devices shall be specifically approved for the application.
2 ) Only neutral grounding devices with a continuous rating shall be permitted where provision is not made
to de-energize the system on the detection of a ground fault.
3 ) Neutral grounding devices not having a continuous rating shall be permitted where:
a ) Provision is made to automatically de-energize the system on the detection of a ground fault; and
b ) The time rating of the device is coordinated with the time/current rating of the protective device
on the system.
4 ) Neutral grounding devices shall have insulation voltages at least equal to the line-to-neutral voltage.
10-1106 location of neutral Grounding Devices and Warning Signs.
1 ) All live parts of neutral grounding devices shall be enclosed or guarded in compliance with Rule 2-202.
2 ) Neutral grounding devices shall be placed in a location that is accessible only to qualified persons to
perform inspection, testing, and maintenance of the neutral grounding device.
3 ) Neutral grounding devices shall be placed in a location so that heat dissipation from the device
under ground fault conditions will not damage or adversely affect the operation of the device or
other equipment.
4 ) Where neutral grounding devices are used, warning signs indicating that the system is impedance
grounded and the maximum voltage at which the neutral may be operating relative to ground
shall be placed at the:
a )Transformer or generator, or both; and
b ) Consumer’s service switch gear or equivalent; and
c ) Supply authority’s metering equipment.
10-1108 Conductors used with neutral Grounding Devices.
(1) The conductor connecting the neutral grounding device to the neutral point of the transformer,
generator, or grounding transformer shall be:
a ) Insulated for the nominal system voltage; and
b ) Identified white or natural grey; and
c ) Sized to conduct the rated current of the neutral grounding device, and in no case less than No. 8
AWG; and
d ) Installed in accordance with other appropriate Rules of this Code.
