Protective grounding represents deliberate electric connection with the earth or metal not current carrying details which can appear energized owing to short circuit on the building. Grounding is intended to eliminate danger of defeat with current from touch to the case, it reduces tension between the building and the earth to safe value. According to rules the measurement of resistance of the grounding device is periodically taken.
It is required to you
- Grounding measuring instrument
Instruction
1. Choose the device for measurement of resistance of a contour of the grounding device. For an example the sequence of actions when using the measuring instrument of grounding of M416 is given. It is intended for measurement of resistance of grounding, active resistance and determination of specific resistance of soil. Measurement range of the device is from 0.1 to 1000 Ohms.
2. Before carrying out measurements it is necessary to reduce quantity of the factors causing an additional error. Install the measuring instrument strictly horizontally, far from powerful electric fields, use only sources food provided by the instruction, define and consider existence of possible sources of hindrances. Hindrances of alternating current and high-frequency radio interferences come to light on fluctuations of an arrow of the device.
3. Install food in the device. Are the power supply three consistently connected galvanic cells of 1.5 V everyone.
4. Set the switch to the position "Control of 5 Ohms", press the button and rotation of the rheochord handle achieve installation of an arrow of the indicator in a zero mark of a measuring scale.
5. Connect connecting wires to the device, previously having examined them and having checked integrity of isolation.
6. Deepen additional auxiliary electrodes (ground wire and the probe) on depth of 0.5 m and connect to them connecting wires.
7. Install the switch in a position of "X1".
8. Press the button, and then rotation of the handle of "rheochord" bring an arrow of the indicator to zero. Increase result of measurement by a multiplier.