UTM-00339 | Rev 19
Page 246 of 253
DetNet South Africa Copyright © 2021
• When joining of the harness wire is required, always use a Back-to Back Connector to ensure a proper
joint. Strip the harness wire insulation a sufficient length to fit into the connector of the Back-to Back
Connector without protruding on either side of the connector as this can result in a short circuit
• Always trim harness wire ends at the end of each channel leaving no bare conductors that could touch or
lie in a conducting solution as this will create a leak path and have a negative impact on the leakage
measurement.
Testing the blast installation with the CE4 Tagger is the last on bench verification that the system deployment is
within the required parameters:
• When a channel is completely harnessed connect the CE4 Tagger to detonator string and perform a “test
all” comparing the number of detonators with the blast plan to ensure all detonators are accounted for.
Check that holes not connected are treated as misfires and marked on the plan. A good rule of thumb is if
leakage exceeds 0.2mA, locate the source and fix before proceeding.
• If the leakage is isolated to a single detonator, remove this detonator from the string and connect this
detonator to a separate harness wire and to its own channel. During programming assign the absolute
time to detonator.
• Ensure that all channels are properly tested and within system limits before connecting to lead-in harness
wire.
• Ensure that all detonators are connected to the correct channels.
Key points to note in testing of the Lead-in wire before rolling it out to the Bench Commander:
• Test total length of lead-in harness wire for short circuits and leakage before connecting to strings of
detonators.
• Make use of Back-to-Back Connectors when joining harness wires.
• When rolling out to the Bench Commander position ensure that wires do not cross blasts or harness wires
that are connected to detonators deployed to the blast, pre-split or near big rocks that might cut harness
wire before the blast signal is sent.
• Keep away from high wall to prevent rolling rocks severing harness wire during deployment or rocks that
may become dislodged by vibration or air blast from other blasts in vicinity.
• If lead-in harness wire requires extension, always use Back-to-Back Connectors ensuring that ends do not
touch, as this could result in leakage or short circuits.
Based on errors that have been observed during the connecting of the harness wire to the Bench Commander, the
following is important to note:
• Ensure that connection points on the Bench Commander are clean and in good condition to ensure a
proper connection.
• Trim Harness wire ends to prevent it from touching the connector face plate to avoid short circuits.
• Fold copper portion double to have a bigger connection area.
• Wrap harness wire around large rocks to provide slack on the harness wire connections to prevent these
from being pulled out by accidental bumping or people traveling.
To Next Page
Loading...