Detection Technology
Field test method of ground resistance tester
The ground resistance tester is a portable ground resistance tester equipped with the necessary test accessories. The instrument is equipped with two pliers, voltage pliers and current pliers. The voltage clamp circuit has excellent induction potential E in the circuit under test and generates current I in the circuit under test. The instrument can measure the value of I by the current clamp. By measuring E and I, the value of R can be obtained according to ohm's law: R = E/I.
The specific field test method is as follows:
(1) when measuring the ground resistance of the two terminals ee, short connect the chrome-plated copper plate, then connect it to the 5m long pure copper wire attached to the instrument, and connect the other end to the ground test unit to be tested. When measuring the resistance of the shielding layer, loosen the chrome-plated copper plate and ground one E terminal and the other E terminal.
(2) the p-column is connected with 20m pure copper wire equipped with meter, and the other end is connected with a pin.
(3) the C column shall be connected with 40m pure copper wire equipped with instrument, and the other end of the wire shall be connected with pin 2.
Current technical requirements of ground resistance tester:
(1) the ground resistance tester shall be placed 1 ~ 3m away from the test point and shall be stable and easy to operate.
(2) the terminals of each terminal must be in good contact and firmly connected.
(3) the two ground electrode pins should be set at 20m and 40m respectively from the left and right sides of the measured ground body. If two pins are connected by a straight line and a wire, the ground to be tested should be essentially on that line.
(4) other wires shall not be used to replace the 5m, 20m and 40m long pure copper wires attached to the instrument.
(5) if the ground resistance tester is used as the center of the circle, the included Angle between the two pins and the tester should not be less than 120° at least, and should not be set in the same direction.
(6) the soil fixed with two pins must be firm and should not be placed near the mud ground, backfilled soil, trees, grass roots, etc.
(7) the ground resistance can only be tested after 7 consecutive sunny days after rain.
(8) the grounding body under test shall be derusted first to ensure a reliable electrical connection.
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