Chapter 2 Installation
12
2.2.2 Current Inputs
To ensure accurate readings, the input current should not exceed 1.2A
RMS and 1.76A amplitude for the 1A CT secondary, or 6A RMS and 8.8A
amplitude for the 5A CT secondary.
Copper wiring 2.5 – 3.5 mm
2
(12 AWG) should be used.
2.2.3 Ground
Connect the chassis ground of the PM172EH to the switchgear earth
ground using dedicated wire greater than 2 mm
2
/14 AWG.
2.2.4 Voltage Inputs
Input of 690V (Standard): To ensure accurate readings, the measured
voltage between terminals 2-5, 5-8 and 8-2 should not exceed 790V AC
RMS, and the measured voltage between terminals 2-11, 5-11 and 8-11
should not exceed 460V AC RMS and 695V amplitude. Use any of the
seven wiring configurations shown in Figures 2-7 through 2-13.
Input of 120V (Option U): To ensure accurate readings, the measured
voltage between terminals 2-5, 5-8, 8-2, 2-11, 5-11 and 8-11 should not
exceed 144V AC RMS and 225V amplitude. 120V input usually implies
use of a potential transformer (PT). The PT requires use of any of the four
wiring configurations shown in Figures 2-9 through 2-12.
Wiring Configuration
(See parameter setup instructions in Section 4.2)
Setup Code Figure
3-wire direct connection using 2 CTs (2-element) 3dir2 2-7
4-wire WYE direct connection using 3 CTs (3-element) 4Ln3 or 4LL3 2-8
4-wire WYE connection using 3 PTs, 3 CTs (3-element) 4Ln3 or 4LL3 2-9
3-wire open delta connection using 2 PTs, 2 CTs (2-
element)
3OP2 2-10
4-wire WYE connection using 2 PTs, 3 CTs (2½ -element) 3Ln3 or 3LL3 2-11
3-wire open delta connection using 2 PTs, 3 CTs (2½ -
element)
3OP3 2-12
4-wire delta direct connection using 3 CTs (3-element) 4Ln3 or 4LL3 2-13
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