Hitachi 670 Series Installation Manual page 75

1MRK514026-UUS Rev. P
be properly connected to the IED chassis with the cable clamp, where the maximum open conductor
length is 40 mm (1.57") between clamp and terminals, see Figure 32. If double shielded cable is used,
the inner cable shielding should be connected at the external equipment end only. At the IED terminal
end, the inner shield should be isolated. The inner and outer shieldings are connected to the external
equipment according to the installation instructions for the actual equipment. Use insulating tape for the
inner shield to prevent contact with the IED chassis. Make sure that the IEDs are properly grounded with
as short connections as possible from the ground screw, for example to an grounded frame.
The IED and the external equipment should preferably be connected to the same battery.
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ANSI07000141 V1 EN-US
Figure 43:
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Installation manual
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Communication cable installation, 2-wire
The inner shields shall be connected together (with an isolated terminal block) and only have one connection
point in the whole system, preferably at the external equipment (PC).
The outer shield shall be connected to the IED chassis in every cable end. Use the shield connection clamp at all
IEDs. The first IED will have only one cable end but all others require two.
Connect according to installation instructions for the actual equipment, observe the 120 ohms termination.
Connect the screens according to the installation instructions for the actual equipment.
Shield connection clamp, see Figure 32.
Communication cable
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Section 6
Connecting
69