Underground Distribution Circuits - Eaton GridAdvisor Series II Installation Instructions Manual

Underground distribution circuits

Primary cable preparation
Proper primary cable preparation is necessary for the
GridAdvisor Series II smart sensor acting as a faulted
circuit indicator to work reliably on underground distribution
circuits. The sensor can be used on concentric neutral, tape
shield, or drain wire cable. If the cable does not provide a
return path for the fault current, the sensor can be installed
directly over the cable. If used on concentric neutral cable,
or if the cable shield provides a return path for the fault
current, the sensor will not reliably detect a fault and will
require the use of a tape shield or drain wire adapter. When
used, the adapter must be installed approximately 3.5"
below the elbow to allow space for mounting the sensor on
the cable.
One of the following four methods is preferred for
installation on concentric neutral primary cable:
Method 1 (refer to Figure 2A)
1. Attach one or two strands of the concentric neutral
wrapped around the cable to the tie-off tab on the
elbow.
2. Terminate all of the remaining neutral wires
approximately 6" below the elbow.
3. Pull the neutral wires straight up and terminate them
again just below the elbow. The wires should then be
bent back down the cable (commonly referred to as
"double back").
4. Terminate the ground wires approximately 6"below the
elbow.
N ote: The sensor is installed over the "double back"
neutral wires to cancel the effect of current in the
neutral. The exact trip value is dependent on the
overall diameter of the "double back" neutral wires.
ELBOW
TIE-OFF
TAB
ELBOW
TERMINATED
NEUTRAL
LOCATE WIRES
THE SENSOR
PORTION OF
THE FAULTED
CIRCUIT
INDICATOR
(in the outlined
area)
NEUTRAL
WIRES
A
Figure 2. Recommended methods of concentric neutral
primary cable preparation
B C
Method 2 (refer to Figure 2B)
1. Attach one or two strands of the concentric neutral
wrapped around the cable to the tie-off tab on the elbow.
2. Terminate all of the remaining neutral wires just below
the elbow. The balance of the neutral wires should be
gathered together and "double backed" down the cable
and grounded.
N ote: The sensor is installed over the "double back"
neutral wires to cancel the effect of current in the
neutral. The exact trip value is dependent on the
overall diameter of the "double back" neutral wires.
Method 3 (refer to Figure 2C)
1. Attach one or two strands of the concentric neutral
wrapped around the cable to the tie-off tab on the
elbow.
2. Terminate and ground all of the remaining neutral wires
approximately 6" below the elbow.
Method 4 (refer to Figure 2D)
1. Arch one or two strands of the concentric neutral
wrapped around the cable and attach it to the tie-off tab
on the elbow.
2. Ensure that the arch is large enough to go around the
outside sensor when the sensor is installed.
In some installations, improper preparation of the primary
cable will result in an inoperable sensor as a faulted circuit
indicator (FCI) (Figure 3). The magnetic field, due to current
in the center conductor, will be cancelled by the current in
the concentric neutral wires.
Do not place the fault indicator as shown in Figure 3. Doing
so will prevent the sensor from working properly.
D
Figure 3. Incorrect methods of concentric neutral
primary cable preparation
Installation Instructions MN915001EN June 2016
GridAdvisor Series II smart sensor
IMPORTANT
A B
3