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SE-330HV Neutral-Grounding-Resistor Monitor
Rev. 5-M-101817
3. I
NSTALLATION
3.1 SE-330HV
Outline and panel-cutout dimensions for the SE-330HV
are shown in Fig. 4. To panel mount the SE-330HV,
insert it through the panel cutout and secure it with the
four included 8-32 locknuts and flat washers.
If an optional SE-IP65CVR-G Hinged Cover is used,
follow the included installation instructions. See Figs. 6
and 7.
All connections to the SE-330HV are made with plug-
in, wire-clamping terminal blocks. Each plug-in terminal
block can be secured to the SE-330HV by two captive
screws for reliable connections.
Outline dimensions and mounting details for surface
mounting the SE-330HV are shown in Fig. 5. Fasten the
optional surface-mount adapter to the mounting surface
and make connections to the adapter terminal blocks.
Follow Fig. 5 instructions to mount or remove the
SE-330HV.
Ground terminal 7 (G) and connect terminal 6 (R) to
the sensing-resistor R terminal.
Use terminal 1 (L1) as the line terminal on ac systems,
or the positive terminal on dc systems. Use terminal 2
(L2/N) as the neutral terminal on ac systems or the
negative terminal on dc systems. Connect terminal
3 (
) to ground.
N
OTE:
Disconnect terminal 1 (L1) and terminal 2 (L2/N)
before performing dielectric strength testing of the control
panel.
N
OTE:
Connections to terminals 4 (SPG) and 5 (SPGA)
are not required when using the SE-330HV hardware
revision 10 and higher. However, it is recommended to
connect terminal 4 to terminal 5 to maintain backwards
compatibility with the older SE-330HV series (hardware
revision 01A and lower).
3.2 S
ENSING
R
ESISTOR
Outline and mounting details for the ER-15KV,
ER-25KV, ER-35KV and ER-72KV sensing resistors are
shown in Figs. 8, 9, 10, 11, and 12. Install the NGR and the
sensing resistor near the transformer or generator. When
installed outdoors, a sensing resistor must be installed in a
suitable enclosure. Ground sensing-resistor terminal G.
Pass the sensing-resistor-to-neutral conductor and the NGR-
to-neutral conductor through the ground-fault-CT window
as shown in Fig. 3. Separately connect sensing-resistor
terminal N and the NGR to the neutral to include neutral
connections in the monitored loop.
Alternately, if the NGR
connection to system neutral need not be monitored,
connect terminal N to the NGR neutral terminal.
If a
ground fault in the sensing-resistor conductor is unlikely, a
minimal loss of protection will result if it does not pass
through the ground-fault-CT window. See Note 3 in Fig. 3.
Outline and mounting details for the ER-1000HV
Sensing Resistor are shown in Fig. 13. This sensing resistor
can be used to monitor a low-voltage very-high-resistance
NGR. See the simplified diagram in Fig. 14.
N
OTE
:
Voltage at terminal N rises to line-to-neutral voltage
when a ground fault occurs. The same clearances are
required for sensing resistors as for NGR’s.
N
OTE:
A parallel ground path created by moisture can
result in a false resistor-fault trip. Moisture sources
include wind-driven rain or snow, and condensation.
Sensing-resistor terminal R and its connection to SE-
330HV terminal R, including interposing terminal blocks,
must remain dry.
N
OTE
:
The neutral-to-sensing-resistor-terminal-N connection
is not a neutral conductor as defined in Canadian
Electrical Code Section 10-1108 and National Electrical
Code Section 250.36(B). It is not required to be 8 AWG
(8.36 mm
2
) or larger. Since current through this
conductor is always less than 250 mA, a 14 AWG
(2.08 mm
2
) conductor insulated to the system voltage is
more than sufficient.
