Micom P721, Техническое руководство

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Pxxx/EN SS/G11
Page 6/8 Safety Section
UL and CSA/CUL Listed or Recognized equipment
To maintain UL and CSA/CUL Listing/Recognized status for North America the
equipment should be installed using UL or CSA Listed or Recognized parts for
the following items: connection cables, protective fuses/fuseholders or circuit
breakers, insulation crimp terminals and replacement internal battery, as
specified in the equipment documentation.
For external protective fuses a UL or CSA Listed fuse shall be used. The Listed
type shall be a Class J time delay fuse, with a maximum current rating of 15 A
and a minimum d.c. rating of 250 Vd.c., for example type AJT15.
Where UL or CSA Listing of the equipment is not required, a high rupture
capacity (HRC) fuse type with a maximum current rating of 16 Amps and a
minimum d.c. rating of 250 Vd.c. may be used, for example Red Spot type NIT or
TIA.
Equipment operating conditions
The equipment should be operated within the specified electrical and
environmental limits.
Current transformer circuits
Do not open the secondary circuit of a live CT since the high voltage produced
may be lethal to personnel and could damage insulation. Generally, for safety,
the secondary of the line CT must be shorted before opening any connections to
it.
For most equipment with ring-terminal connections, the threaded terminal block
for current transformer termination has automatic CT shorting on removal of the
module. Therefore external shorting of the CTs may not be required, the
equipment documentation should be checked to see if this applies.
For equipment with pin-terminal connections, the threaded terminal block for
current transformer termination does NOT have automatic CT shorting on removal
of the module.
External resistors, including voltage dependent resistors (VDRs)
Where external resistors, including voltage dependent resistors (VDRs), are fitted
to the equipment, these may present a risk of electric shock or burns, if touched.
Battery replacement
Where internal batteries are fitted they should be replaced with the recommended
type and be installed with the correct polarity to avoid possible damage to the
equipment, buildings and persons.
Insulation and dielectric strength testing
Insulation testing may leave capacitors charged up to a hazardous voltage. At the
end of each part of the test, the voltage should be gradually reduced to zero, to
discharge capacitors, before the test leads are disconnected.
Insertion of modules and pcb cards
Modules and PCB cards must not be inserted into or withdrawn from the
equipment whilst it is energized, since this may result in damage.
Insertion and withdrawal of extender cards
Extender cards are available for some equipment. If an extender card is used,
this should not be inserted or withdrawn from the equipment whilst it is energized.
This is to avoid possible shock or damage hazards. Hazardous live voltages may
be accessible on the extender card.