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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
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