Electrical equipment is effectively grounded 20, and electrical equipment is effectively grounded

The device is grounded. The amount of work is not small, but I am afraid that you will not care if you see it.

For plant equipment grounding.

If you want to reliably ground, do the ground net, find a vacant land, moist well, the area of 10 meters * 10 meters, you can divide this piece of land into the word "day", "eye" or "field" word, dig down 30 cm or less according to the frame, dig every 2-3 meters into a 2-meter-long angle iron, about 10 or so, and then use round steel to weld these angles with a welding machine, weld the dug up soil well, and the ground grid leads out a fixed as equipment grounding, If you want to know how big the grounding resistance of this ground grid is, find a grounding resistance meter (shake meter) to measure, if the grounding is good, the resistance should be less than 10 ohms, the smaller the better, after doing these work, you can connect all the equipment to this ground grid.

For household appliances, some power cords are two-ended plugs, and such appliances generally do not need to be grounded. When the electrical equipment without grounding terminals needs to be grounded, the grounding wire can be connected to the metal base of the equipment and other parts that do not affect the operation of the equipment, and the grounding point must be polished clean to ensure good grounding. In addition, the grounding resistance of the grounding electrode should be guaranteed to be less than 4 ohms, and the cross-section of the grounding wire should meet the technical requirements.

Standard Ground Resistance Specification Requirements:

1. The grounding resistance of independent lightning protection should be less than or equal to 10 ohms;

2. The grounding resistance of independent safety protection should be less than or equal to 4 ohms;

3. The independent AC working grounding resistance should be less than or equal to 4 ohms;

4. The independent DC working grounding resistance should be less than or equal to 4 ohms;

5. The anti-static grounding resistance is generally required to be less than or equal to 100 ohms.

6. The common grounding body (joint grounding) should not be greater than the grounding resistance of 1 ohm.

The grounding of electrical equipment belongs to safety grounding, if it is an independent equipment, it should not be greater than 4, and if it is a public grounding, it should not be greater than 1.

1. The part that should be grounded.

Metal housings or frames for motors, transformers, switchgear, lighting appliances, mobile electrical equipment, power tools.

Electrical drives.

Secondary coils for electric transformers and current transformers (unless otherwise required for relay protection).

Metal components such as indoor and outdoor power distribution devices, consoles, and metal fences and metal doors near live parts.

Cable termination box housings, cable metal sheaths and metal brackets.

Electrical equipment installed on distribution line towers, such as lightning arresters, protective clearances, fuses, capacitors and other metal shells and reinforced concrete towers.

2. The part that does not need to be grounded.

In a dry room with poorly conductive floors (wooden, asphalt, etc.), the metal casing of electrical equipment does not need to be grounded when the AC voltage is 380V and below and the DC rated voltage is 400V and below. However, when the maintenance personnel can reach other grounded objects in other electrical equipment at the same time for some reason, they should be grounded.

In dry places, when the AC rated voltage is 36V and below and the DC rated voltage is 110V and below, the electrical equipment shell does not need to be grounded, except in case of **sexual danger.

Metal frame in the battery chamber with a voltage of 220V and below.

If the electrical equipment and the base of the machine tool can be reliably grounded, only the base of the machine tool can be grounded.

Appliances that can be removed from grounded metal frames and power distribution units.

The grounding wire in the power system is a lifeline that protects people's lives to a certain extent, as long as the electrical facilities and equipment endanger the safety of human life, the grounding wire must be installed.

Generally, the metal shell must be grounded

The function of grounding protection of electrical equipment is to prevent electric shock, that is, to connect the metal shell of electrical equipment with the grounding body to prevent the operator from contacting the equipment shell and being electrocuted when the shell is energized due to damage to the insulation of the electrical equipment.

In a low-voltage system where the neutral point is not grounded, under normal circumstances, the exposed parts of the uncharged metal of various electrical installations should be grounded unless otherwise specified. Such as:

1) Housings of motors, transformers, electrical appliances, portable and mobile electrical appliances.

2) Transmission devices for electrical equipment.

3) The frame of the power distribution screen and the control panel.

4) The outer shell of the cable and the junction box and terminal box of the power cable.

5) Metal protection pipes for power lines, laying steel cables and crane tracks.

6) Towers equipped with lightning arrester power lines.

7) Housings and brackets of power devices such as switches and capacitors installed on power line towers.

The exposed conductive parts of electrical equipment must be grounded, including but not limited to the exposed conductive parts listed below: (1) metal bases and shells of motors, transformers, electrical appliances, portable electrical appliances and mobile electrical appliances. (2) The metal box of the box-type substation, the shell of the generator neutral point cabinet, the shell of the generator outlet cabinet, and the closed bus shell.

3) The metal shell of the junction box, terminal box and expander of AC and DC power cables and the metal sheath of the cable, the metal trunking and cable tray of the steel pipe laying cable that can be touched and threaded; electrical equipment transmission devices; Exposed conductive parts of metal lighting fixtures. (4) Metal frames and bases of screens, cabinets, boxes and operating consoles for power distribution, control and protection, and metal shells of fully enclosed combined electrical; Metal and reinforced concrete frames for indoor and external power distribution installations, as well as metal fences and metal doors near live parts. (5) metal towers and reinforced concrete towers of overhead power lines; Exposed conductive parts and brackets of switchgear, capacitors, and other electrical devices installed under power line towers.

Protective grounding of electrical equipment is one of the important measures to ensure the safety of equipment and working environment. Here are some common grounding guidelines for electrical equipment protection:

1.Equipment Grounding: All electrical equipment should be properly grounded, including power outlets, power switches, distribution boxes, motors, etc. Grounding can be connected to a grounding rod or grounding grid by a grounding wire.

2.Grounding resistance: Grounding resistance refers to the resistance value of the grounding system, which should comply with relevant national or industry standards. The lower ground resistance effectively directs the fault current underground, reducing the hazard to equipment and personnel.

3.Grounding Lines: Grounding lines should be copper or aluminum wires with sufficient conductive cross-sectional area and should maintain a continuous, reliable grounding path.

4.Grounding marking: The docking point is marked, and obvious grounding signs are used to ensure that the personnel can easily find the grounding point.

5.Integral grounding: The equipment should be grounded as a whole to prevent the generation of residual voltage of electrical equipment to ensure that the equipment does not pose a risk of electric shock to personnel.

6.Equipment grounding lead: In order to facilitate equipment maintenance and overhaul, it is necessary to set up a reliable grounding lead on the equipment to facilitate personnel grounding operation.

7.Regular Testing: Regularly check the resistance and connectivity of the grounding system to ensure the effectiveness of the grounding system. This can be achieved by using a professional test instrument for measurements.

To be able to be you, a little bit of attention, a little like, thank you!

In the TN-S system, the PE of the equipment can be directly connected to the electrical PE, and it is the recommended practice. This guarantees the equipotential of the device. Lightning protection and grounding is a system for buildings and electrical equipment, communication systems to prevent damage caused by lightning strikes, including lightning connectors, down conductors and grounding, as well as surge protection and other equipment.

The grounding system can be shared with the grid grounding system, and it can also be set separately. Working grounding is the grounding of electrical appliances, which mainly refers to the measures to connect transformers, generators and other shells and center lines with the earth to ensure the safety of the power supply system and electrical safety.

Working grounding is to ground the neutral point of the transformer. Its main function is the stability of the system potential, that is, to reduce the danger of overvoltage caused by the low-voltage system due to one-phase grounding, high-voltage and low-voltage short circuit, etc., and to prevent insulation breakdown.

Protective grounding refers to connecting the metal part of the electrical device that is not charged under normal conditions with the grounding device to prevent the part from suddenly being charged in the case of a fault and causing harm to the human body.

1. The definitions are different.

In order to ensure the reliable operation of electrical equipment under normal or fault conditions, grounding a certain point in the power system is called working grounding.

Grounding the exposed conductive portion of a device that may present a dangerous voltage to ground in the event of a fault is called protective grounding.

2. The role is different.

Working grounding: It can maintain the non-fault relative ground voltage unchanged; It can ensure the accuracy of relatively low voltage measurement in the primary system; When lightning strikes, lightning current is discharged to the ground.

Protective grounding: In order to ensure personal safety and avoid or reduce the hazard of accidents, protective grounding is often used in electrical engineering.

3. The scope of application is different.

Working grounding: the neutral point of the power supply (generator or transformer) is directly grounded (or through the arc suppression coil), the neutral point of the primary side coil of the voltage transformer is grounded, and the lightning protection equipment is grounded.

Protective Grounding: A metal enclosure on electrical equipment that is insulated from a dotted part.