Earthing devices and electrical safety

Any electrical appliance can break. If he just stopped working - it's half bad. Worse, if a fault causes an electrical voltage to fall on the elements of its design that the user considers to be safe. Carelessly touching such an object, a person will be subjected to an electric shock, may be injured or even worse ...

What is a protective ground?

With an internal break of the conductor, it becomes possible to touch the body of the electrical board or other device, and in this case the latter will be a deadly danger, invisible, and that is why the doubly terrible one. To avoid such situations, grounding devices are used. Mounted, they are very simple, but certainly must meet a number of requirements.

Outdoor equipment, as well as any equipment located in humid premises, must be grounded and nullified if the supply voltage exceeds 42 V AC, or 110 V DC. The same applies to all metal non-current parts of power tools, boxes, shields and structures in which the cable is carried.

What does grounding consist of?

Earthing devices consist of two main parts.

The first of these is called a grounding rod, and most often is a natural building element, such as fittings, buried pipelines and other parts that provide reliable and repeated contact with the ground. If, due to some circumstances, such structures are missing or inaccessible, artificial earthing devices are used. They are steel corners buried in the ground to a depth of at least 60 cm with a side dimension of 5 cm and a thickness of at least 4 mm. The length of each of these elements must be at least 3 meters, they go deep into the ground, then steel strips are welded to them, to which the conductors are fastened, that is, the second part of the structure providing electrical safety.

Grounding Requirements

The resistance of the grounding device should be minimal, so the requirements for reliability of the contact are very high. Its main purpose is to create the conditions for the power outage in case of contact of the live part with elements that under normal conditions should not be under voltage. On how quickly there is an emergency de-energization, often depends on human life.

Ground condition monitoring

In order to control the degree of electrical safety, a periodic earthing device is measured. The physical meaning of this procedure is to determine the actual resistance by which the current will flow in an emergency situation. To do this, special instruments are used, equipped with test probes and representing an accurate ohmmeter (for example, MRU-101).

At the enterprises for electrical safety, specific officials are responsible, usually the chief power engineer, the head of the labor protection service and, of course, the management. In their own apartment, cottage or private structure, grounding devices are controlled by the owners of the property.

Be careful and careful!