Norms of acceptance tests. Grounding devices

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 1 General Rules

Norms of acceptance tests. Grounding devices

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Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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1.8.39. 1. Checking the elements of the grounding device.

The check should be carried out by inspecting the elements of the grounding device within the scope of inspection. The cross-sections and conductivities of the elements of the grounding device, including the main grounding bus, must comply with the requirements of these Rules and design data.

2. Checking the circuit between ground electrodes and grounded elements.

The cross-sections, integrity and strength of the conductors, their connections and connections should be checked. There should be no breaks or visible defects in the grounding conductors connecting the devices to the ground electrode. The reliability of welding is checked by hitting a hammer.

3. Checking the condition of breakdown fuses in electrical installations up to 1 kV.

Breakdown fuses must be in good working order and correspond to the rated voltage of the electrical installation.

4. Checking the phase-zero circuit in electrical installations up to 1 kV with a TN system.

Verification is performed in one of the following ways:

direct measurement of single-phase fault current to the housing or neutral protective conductor;
by measuring the total resistance of the phase-neutral protective conductor circuit with subsequent calculation of the single-phase fault current.

The multiplicity of the single-phase ground fault current in relation to the rated current of the fuse or circuit breaker release must be no less than the value specified in Chapter 3.1 of the PUE.

5. Measurement of the resistance of grounding devices.

The resistance values of grounding devices with connected natural grounding conductors must satisfy the values given in the relevant chapters of these Rules and Table 1.8.38.

6. Measurement of touch voltage (in electrical installations made according to touch voltage standards).

Touch voltage measurement is carried out with connected natural ground electrodes.

Touch voltage is measured at control points at which these values are determined by design calculations (see also 1.7.91).

Table 1.8.38. The highest permissible resistance values of grounding devices

Type of electrical installation	Characteristics of the electrical installation	Resistance, Ohm
1. Substations and distribution points with voltages above 1 kV	Electrical installations of electrical networks with solidly grounded and effectively grounded neutral.	0,5
	Electrical installations of electrical networks with an isolated neutral, with the neutral grounded through an arc suppression reactor or resistor.	250 / I_р^*
2. Overhead power lines with voltage above 1 kV	Grounding devices for overhead line supports (see also 2.5.129 - 2.5.131) with soil resistivity, ρ, Ohm m:
	- up to 100	10
	- more than 100 to 500	15
	- more than 500 to 1000	20
	- more than 1000 to 5000	30
	- more than 5000	ρ 6 10^-3
	Grounding devices for overhead line supports with arresters at the approaches to switchgears with rotating machines	see chapter 4.2
3. Electrical installations with voltage up to 1 kV	Electrical installations with power supplies in electrical networks with a solidly grounded neutral (or midpoint) of the power source (TN system):
	- close to neutral	15/30/60 ^**
	- taking into account natural grounding and repeated grounding of outgoing lines	2/4/8 ^**
	Electrical installations in electrical networks with an isolated neutral (or midpoint) of the power source (IT system)	50 / I ^***, more than 4 ohms are not required
4. Overhead power lines with voltage up to 1 kV	Grounding devices for overhead line supports with repeated grounding switches PEN (PE) - conductor	30

* Ir - rated earth fault current;

** - respectively, at linear voltages of 660, 280, 220 V;

*** I - total earth fault current.

See other articles Section Rules for the installation of electrical installations (PUE).

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