T-305E User Manual Version 3.5 | 15
5.
Getting started
Before operating the instrument, ensure that the cable under test is without power, fully
discharged (see below) and totally isolated.
5.1
Using the discharge rod
The discharge rod supplied with T-305E is multi-sectional and retractable, and in the first
section a discharge resistor is embedded. The discharge procedure consists of three stages:
air ionisation discharge, resistance discharge and direct grounding discharge.
i.
Connect the discharge rod cable to the rod and attach it securely to a suitable
grounding point using the crocodile clip.
ii.
Holding the handle of the rod, slowly let its metallic point approach the HV test item.
During this process, a crackling discharge sound can be heard. This is air ionization
discharge.
iii.
After the air ionisation discharge becomes weak, the point of the rod can make
contact with the HV test item directly. At this time, the item will be discharged
through the discharge resistor inside the rod. The reading of the KV voltmeter will
drop down.
iv.
When the reading of the KV voltmeter drops to less than 5kV, use the earth contact tip
of the discharge rod to directly ground the item.
5.2
Wiring connection
i.
Preliminary work: disconnect the faulty cable with other devices and ground the metal
sheath. This is the Working Ground, the zero-volt reference point during the discharge
process.
ii.
Position the T-305E at about 2m away from the faulty cable, and put the cable fault
locator on the tray at the side panel for easy operation.
iii.
Connect the testing cables according to the figure shown below:
Note: The protection ground and the auxiliary ground must be grounded separately,
otherwise the system is not safe.
Figure 5.1 T-305 Connections
