Checking the ground loop in the socket with a multimeter

During commissioning, electrical appliances in apartments and houses provide normal conditions for the passage of current. In order to protect against electric shocks in the premises, grounding is arranged. The work is necessary so that the “land” and the potential of the housing of household appliances are equal. Self-checking of grounding is carried out using special equipment.

Grounding Overview

Grounding is a device that prevents the risks of electric shock when connecting devices to the ground. The system consists of a grounding conductor connected to the ground electrode, and is a metal plate or wire. By design, it happens:

• working - ensures the quality of the functions of the electric network;
• protective - prevents injuries from electric shock.

The average apartment is equipped with single-phase wiring with alternating current (positive and negative charge). Under conditions of voltage fluctuations, the current changes direction - the charge is transferred to the equipment, and not diverted from the line. A person may be shocked by touching an electrical appliance. Equipment in such cases fails. The device transfers electrostatic or electric charge to earth or to a zeroing device.

Technical standards of manufacturers of metal household appliances indicate the need to ground connection lines.

Why grounding is checked

Testing the grounding condition protects a person from electric shock. Special equipment is used in a private house or apartment, representatives of a service company are involved in the work. Based on the results revealed:

• the condition of the ground line and its performance;
• compliance with technical standards;
• condition of soil and electrodes, grounding conductors, tires, metal communications nodes;
• the need to replace circuit connections in the event of wear;
• the need to install an RCD in conjunction with the "ground".

Periodic planned measurement in residential buildings is made 1 time in 3 years.

Grounding Devices

To check the grounding in the house or apartment yourself, it is worth starting with the selection of equipment. Professional electricians use several devices:

• arrow - models with generators of small dimensions are used as autonomous power sources and rotate manually;
• arrowheads with power from a galvanic battery;
• digital - data is displayed on the LCD display, batteries and non-contact “pincers” are included.

Independently, the grounding line can be checked using the M-416 device. The arrow megaohmmeter of the old release allows you to get accurate data for a reliable assessment of the condition of the line. Measurement limits are set on a dial ohmmeter. The connection diagram is indicated under the cover.

Using the M-416, you can measure the contour resistance and soil performance.

Verification Methodology

Checking the ground loop is carried out according to a single algorithm:

1. Stripping the tire for good contact.
2. Driving into the ground for 50 cm 2 additional pins.
3. Connection of tires to pins with clamps of the device according to the scheme.
4. Taking measurements according to the instructions for the device.

Place the electrode “C” at a distance 5 times the length of the ground electrode of the vertical. Remove pins from underground utilities for data accuracy.

Technology of work with the M-416 device

If during the visual inspection on the ground line no breakages are detected, you can recognize the condition of the circuit using the M-416 device. The work is carried out as follows:

1. Checked power supplies. The device must have 3 batteries of 1.5 V each.
2. The device is placed horizontally on a flat surface.
3. Calibration in progress. The range switch is set to “5Ω Control”.
4. The arrow is set to the zero position. You need to press the red button and scroll the rechord knob. The scale displays 5 ± 0.3 ohms.
5. The meter is placed at a minimum distance from the ground electrode. This will help prevent the influence of the resistance of the connecting wires on the overall result.
6. A check is carried out according to the scheme under the cover of the device. The main and auxiliary electrodes will need to be driven into the soil to a depth of 50 cm.
7. Calculations are being made. With a resistance of less than 10 ohms, the total should be multiplied by 1, and the switch should be transferred to x1. If the total measurement is more than 10 ohms, the switch is switched to x5, x20, x100.

Remove paint from the connection point between the wires and the ground before measuring.

Grounding check in outlets

You can independently determine the grounding in the outlet in several ways. Before starting work, an indicator screwdriver will be needed - it identifies zero and phase wires. If a light comes on when contacting a terminal, this is a phase. If the indicator does not light, it is zero.

Multimeter check

Testing is carried out even if the colors match the standards. You need to work with a multimeter like this:

1. Turn on the power to the house in the switchboard.
2. Measure voltage at outlets. One probe is placed in phase, the second in zero.
3. Move the probe probe from zero to the ground conductor - PE.
4. See what the tester shows. If the result has not changed - everything is in order with the system. If the indicators are zero - the system must be grounded again.

Use tools that have insulation on their handles. If checking the bathroom, do not step on a damp floor.

Check by a control bulb

To make the control, you will need a light bulb with a cartridge and two copper wires attached to it. Between all the contacts of the home-made device, insulation is needed. Verification by control is carried out according to the principle of a multimeter:

1. The first probe is connected to zero, the second to phase.
2. The probe moves from zero to ground.
3. The serviceability of the circuit is indicated by a lit lamp.
4. Weak light indicates a malfunctioning circuit and the need to install an RCD.

When the room is wired without color indicators, you can find out the grounding as follows:

1. To determine the zero and phase, one trailer is output to the ground terminal, the second - in turn to other connections.
2. The phase is at the tanning point of the light indicator.
3. If the lamp does not light, PE does not work.

If the lamp does not light up due to phase contact, the power supply to the switchgear and the lamp itself are checked. Sometimes it does not work due to a broken phase or zero circuit.

Indirect evidence of lack of PE

There are several points by which we can judge the absence of PE. Owners of apartments and houses should be alert:

• stable electric shocks from a boiler, washing machine, dishwasher, refrigerator;
• column noise when playing music;
• the presence of a large amount of dust near old batteries.

Call specialists immediately - in case of serious short circuits on the lines there are risks of death from electric shock.

Testing with an arrow (digital) voltmeter

Checking the voltage and its presence is carried out using AC voltmeters.Switch devices operate without a power source, while digital devices function in any position and are not damaged by mechanical stress.

The correct algorithm for using a voltmeter:

1. The maximum permissible measurement value for the device is determined by the largest number on the scale.
2. Refinement of the unit of measurement of the device - microvolts, volts, millivolts.
3. Connecting a voltmeter parallel to a section of the electrical network and polarity control with a wire.
4. Screwing the wires of the switch device to the nuts and screws. Constant voltage models have the plus and minus signs.

For mains voltages greater than 60 V, work with dielectric gloves and use insulated probes.

Features of checking in an apartment and a private house

The technology of grounding testing for a house and an apartment has several differences.

Testing in the apartment

It is necessary to ground all objects made of metal - radiators, a bathtub, household appliances. It is also worth protecting the sockets and clarifying whether the third contact is included in the circuit. There are several tricks.

Screwdriver + tester + insulated wire

Used wire with probes at both ends. They work like this:

1. Check the voltage at the outlet using a tester, a desk lamp, charging for a smartphone. Insert the plug into the outlet very carefully.
2. The working outlet is turned off through the RCD of the shield, switching the machine.
3. Remove the cover from the outlet and inspect the connection of the ground contact. It connects to a separate cable or zooms out with terminals.
4. Assemble the outlet and turn on the RCD.
5. If there is ground, make a check with a tester or indicator screwdriver. The contact must not be connected to the phase.
6. Check the grounding of the wire - find the phase, remove the finger from it and place the probe on the sensor. It should not burn.

The serviceability of the "earth" is indicated by a tanning or increased brightness of the indicator.

Careful check with a long wire

You will need an indicator screwdriver, a tester and a long probe. The work algorithm is as follows:

1. The electrical panel is opened, an indicator-screwdriver inspects the yellow-green wire for the absence of voltage of the ground loop.
2. Find "zero" (blue wire) and attach to it a probe of the conductor. Another probe touch the yellow-green wire. By the operation of the machine, you can judge the serviceability of the wire.
3. Return the RCD handle to the platoon. One end of the wire remains at zero, the other touch all outlets and metal products in the room. With a good circuit, the machine is triggered.
4. Checked bathroom. At 50 cm from the floor there is a SOU box with a metal bus and wires. There should not be stress.

After checking the voltage in the bathroom, tighten the connections of all the bolts.

Check in a private house

The measurement procedure for a private house has significant differences from work in the apartment.

Testing the health of soil and metal bonds

Activities include visual inspection and the use of special devices:

1. For visual inspection, it is necessary to hit the contacts with a hammer with an insulated handle. The conductor should rattle.
2. Checking the resistance of metal components with an ohmmeter or multimeter. The permissible result limit is 0.05 ohms.
3. Grounding terminal on another site with a difference in measurements with normative.

Check the soil and metal connections in summer or spring - at this time there is less rainfall.

Testing without a tester and voltmeter

Using a light bulb and a cartridge with two wires, you can determine the presence of grounding in the country:

1. Strip the ends of the wire from the insulation and insert into the socket - the lamp will light up.
2. Correctly measure the grounding probe: remove one of the wires and touch the grounding point.In the absence of lamp ignition, the wire is removed from another hole.
3. If the RCD works, the grounding is of good quality.
4. Look at the glow of the lamp. When connecting the phase and ground, it is brighter than when connecting the phase and zero.

Using indicators for Euro outlets, you can detect all the flaws in the connection.

Solving connectivity issues

If checking the ground loop with home-made control, a voltmeter or multimeter does not give a result, you will need:

• Connect the appliance to the network without touching the contact and see if it will work.
• Turn off the power in the switchboard, remove the plug from the outlet.
• Disassemble the socket and inspect the wires, the connection points of the contact. No ground if no connection.

Independent work with the electric network in violation of the algorithm can cause injuries and fires as a result of a “zero” break. To prevent this, use the services of electricians.