The electrical accidentes is produce by the contact of a person with active parts in tension and can be of two types:

- Direct contact.

- Indirect contact.

 

The electrical accidents os accidentes eléctricos they are a type of very frequent accident in Spain.

 

DIRECT CONTACTS

They are the contacts of people with active parts of materials and equipment. Denominating active part to the set of conductors and conductive pieces under in good condition normal tension.

The direct bondings can settle down of three forms:

- Direct bonding with two active conductors of a line.

- Direct bonding with conductive assets of line and mass or earth.

- Unloading by induction. They are those accidents in which an electrical shock without the person has touched physically metallic part or in tension of an installation takes place.

 

The protection against direct bondings can be obtained of three forms:

1 - Distance of the active parts of the installation.

One is to move away the active parts from the installation to a distance of the place where the people habitually are or circulate, of such form that is impossible a fortuitous contact with the hands.

The volume of security and distance of protection are 2,5m in height and 1m in horizontal.

 

2 - Interposition of obstacles.

Obstacles will interpose that prevent all accidental contact with the active parts of the installation. These must be fixed of safe form and to resist the mechanical efforts that they are put under.

They can be: Insulating partitions, grates, screens, boxes, covers, etc.

One of the best insulators is the wood.

 

3 - Covering of the active parts of the installation.

It will be made by means of an isolation appropriate, able to with time conserve his properties and that the current of contact limits a value nonsuperior to 1mA.

 

Complementary measures:

- The use of naked conductors will be avoided.

- When they are used, effectively they will be protected.

- Is prohibited the use of switches of blades that properly are not protected.

- The fuses will not be in the open.

Habitually domestic accidents with our electrical apparatuses take place.

 

INDIRECT CONTACTS

He is the one that takes place by effect of a failure in a receiver or accessory, turning aside the electrical current through the metallic parts of these. Being able by this cause to make contact the people with enemy with some element that does not comprise of the electrical circuit and that in normal conditions must not have tension like:

- Current of derivation.

- Situation within a magnetic field.

- Electrical arc.

For the election of the measures of protection against indirect bondings, the nature of the premises will consider or locations, the conductive masses and elements, the extension and importance give the installation, that will force in each case to adopt the measurement of adapted protection more.

Las medidas de protección contra contactos indirectos:

1 - Ground of the masses.

To ground the masses means to unite to the terrestrial mass a point of the electrical system (housing of machines, tools, etc).

 

2 - Trafos. of 24V.

It consists of the use of small tensions of security that as it is specified in the R.E.B.T will be of 24V for the humid or wet premises and 50V for the dry premises.

This system of protection gives to take others against the indirect bondings in the circuit of use.

The use of security tensions is advisable when it is about facilities or apparatuses whose active parts have functional isolation and must very be used in places conductors. This it is the case of:

- Portable lamps.

- Electrical tools.

- Toys driven by electrical motor.

- Apparatuses for the treatment of the hair and the skin.

- Works in boilers, containers or deposits, pipes of conduction, etc.

Portable lamp TECNOCEM made acording to the effective norms of the CEE.

 

3 - Separation of circuits.

The neutral one consists of even separating the circuits of use of the power plant by means of transforming isolated earth maintenance all the conductors of the circuit of use.

This system is advisable in boilermaking, naval construction, metallic structures and in general in conditions of work where the contact of the individual with mass is very good for being raises, together or inside metallic pieces of great dimensions.

This system of protection gives to take other measures against indirect bondings.

 

4 - Double isolation.

It consists of the use of materials that have isolation of protection or reinforced between their active parts and their accessible masses.

It is an economic system since it demands the installation of protection conductor. Its effectiveness does not diminish with time when not seeing itself affected by corrosion problems. All the apparatuses with double isolation take the symbol.

Between its ample ones and varied applications we can mention: Manual, small switchboards, tools household-electric (beaters, molinillos, exprimidores, etc.), machines of offices, (calculating electrical, typewriters electrical, etc).

Portable lamp specially design by the work in mechanical factories.

 

5 - Interrupting differential.

It protects against indirect bondings the people, by lack or failure of isolation