With all the advantages of electrical wiring it is a means of high-risk and poses a real threat to the life of all members of the household, without exception, in the event of faults.
To reduce the risk of electric shock grounding apply: compulsory connection to the land and buildings other metal parts of electrical equipment, while using the voltage of 50 V AC current. When an insulation fault voltage is shorted to ground potential, and the housing is reduced to a safe level.
To perform the grounding cable is introduced into an electric wire with an additional characteristic yellow-green insulation.
An example is shown in Figure 1.
Grounding functions effectively only when a serviceable condition corresponding circuits. Their test can be performed with simple means.
Preliminary testing stages
All the procedures described below can be performed only at the disconnected network. The easiest way to de-energize it with the introduction of shield machines.
First the visual assessment of the existence and serviceability of grounding.
To do this with any of the outlets remove the lid and check:
- connect the wires to the earthing contact;
- the integrity of the wires;
- the absence of its connection to any other wire of the same cable.
In the presence of the compound in the latter case the network is built from vanishing, whose efficiency is markedly lower.
Checking tester
This kind of test tool provides the most objective results on the state of the ground loop.
Check itself is performed as follows:
- include automatic opening flap;
- tester is converted into AC voltage measurement mode in the range 750 - 1000 B;
- determining voltage phase - zero (should differ little between 220 - 235 V, as shown in Figure 2);
- the second measurement is performed between the earthing contact socket and phase readings tester must change slightly.
The big difference in the testimony talks about ground loop fault: high resistance or even rupture.
Checking lamp-control print
Under the lamp-control print understand conventional 220 volt lamp, which is provided with two wires of approximately 30 cm with the contacts at the free ends, see Figure 3. These wires are for convenience often attach to the contacts of the cartridge and a light bulb screwed into it already.
When such a method is necessary to identify the probe screwdriver-phase wire. Then, contact the probe connected to the zero and phase conductor, the lamp should illuminate brightly. When you transfer contacts from one of the neutral wire to the ground when the ground brightness proper circuit should not be changed.
Verification of RCD
Modern apartments and houses are often equipped with residual current circuit breaker. RCD is implemented as a module that is mounted on the output of the input automaton and its circuit is triggered by the appearance of even a small leak to the ground point.
This property is used for verification. The leakage current appears when connecting two wires tester or bulb-control print between earth and phase conductor. Thus, the trip limit indicates the health of the grounding circuit.
conclusion
Protective earth performs important functions and should be serviceable. Check its performance is not a big problem and can be done even the simplest means at hand.
Ground it is advisable to check when buying a new living space, repeating after about five years of prophylactic reasons.