In the following overview you will find important information on the correct handling of electrical cables and lines.
Thermal influences
Cables have to be chosen, layed or installed in a way that the expected current heat emission is not impeded and thus does not create any fire risk for adjacent materials. The limit temperatures of the individual cable types are shown in the catalogue. The indicated values shall not be exceeded by the combined effects of internal current heat and environmental conditions.
Mechanical stress
Any possible mechanical stress which could lead to a mechanical damage of the layed cable has to be considered before installation.
Torsional stress
Flexible cables are generally not appropriate for torsional stress. In cases where torsional stress cannot be avoided, the construction of the cable and the way of laying have to be agreed upon between the user and SAB Bröckskes.
Tensile load
The following values for the tensile load of each conductor shall not be exceeded. This is valid for a max. value of 1000 N for the tensile load of each conductor, as far as no other deviating values have been accepted by SAB Bröckskes. 50 N/mm² for the installation of cables for fixed laying. 15 N/mm² static tensile load for flexible cables and for fixed laying in case that the cables are used for fixed installed electric circuits.
Wherever those values are exceeded, it is recommended to use separate strain relief elements or similar. The connection of such a strain relief element with the cable has to be executed without damaging the cable. In case that flexible cables are exposed to dynamic tensile load (including tensile load due to mass reactance, for example on unwinding spools), the allowed tensile load or the duration of wear of the cable have to be agreed upon by the user and SAB Bröckskes. Instructions for the vertical laying of cables without any intermediate fixing are shown under EN 50656-1 pos. 5.6.2.
Bending load
The inner bending radius of a cable has to be chosen in a way that any damage of the cable is avoided. The inner bending radii for the different cable constructions are indicated in table 6 of HD 516. The choice of smaller bending radii than indicated in the cable catalogue has to be agreed upon with SAB Bröckskes.
The stripping of the cable sheath shall not cause any damage to the conductor as otherwise there will be a considerable deterioration of the bending characteristics. The indicated bending radii are valid for ambient temperatures of (20 ± 10) °C. For other ambient temperatures please contact SAB Bröckskes.
Bendings directly beside external of internal fixing points have to be avoided.
Compatibility
For the choice and laying of cables the following points have to be considered:
| Mechanical and electrical impacts between adjacent electric circuits have to be avoided. |
| Heat loss of cables or chemical/physical influences of the cable materials on adjacent materials, for example construction or decoration materials, in sulating tubes and fixing device. |
| The influence of the current heat on the conductor material and connections has to be considered. |
For further indications please see tables 3A, 3B, 4A and 4B of HD 516.
Room types
| Electric shops of the factory are rooms which are generally used for the operation of electric equipment and the access is only allowed to instructed staff members, for example switch rooms. |
| Closed electric shops are rooms which are only used for the operation of electric equipment and are generally locked up. The access is only allowed for instructed staff members, for example closed switch and distribution systems. |
| Dry rooms are rooms without any condensation water in which the air is not saturated with humidity, for example living rooms and hotel rooms. |
| Damp rooms are rooms in which the safety of the operational devices is affected by humidity, condensation water, chemical or similar influences, for example in large kitchens. |
General notes
Rooms can only be classified in one of the above mentioned types by a careful inspection of the rooms and operational conditions. If there is only much humidity in a certain area of a room but the room is nevertheless dry due to good ventilation, there is no need to classify the room as a damp one.
Application in rooms and in the open air
General:
These terms have to be understood in connection with the boundary conditions (for example min. and max. operating temperatures, influence of ambient temperatures) defined by the construction and the intended application.
Terms for application types:
Application in rooms:
The cable is installed or connected to a device which is normally located in a building within „a planned surrounding”. The building can be used for business, industrial or living purposes.
Limited application in the open air:
The cable is appropriate for a short-time use in the open air, „planned surrounding” for example lawn mower.
Permanent application in the open air:
The cable has been constructed for different conditions which can occur in the open air „planned surrounding” (including different weather conditions).
Stress classification
The term „stress“ describes the use of cables in certain areas, connected to or installed in devices and for certain combinations of external influences which can occur in those areas. On the base of mechanical influences and general expressions the term „stress“ has been divided into four categories:
Very light stress: | Application areas, in which the risk of mechanical damage and stress is very small, for example electric razor. | |
Light stress: | Application areas, in which the risk of mechanical damage and stress is small, for example hair dryer. | |
| Normal stress: | Application areas, in which the cables are exposed to small mechanical stress and the risk for mechanical damage is small, for example small stoves. | |
| Heavy stress: | Application areas, in which the risk of mechanical damage or mechanical stress is of medium impact, for example machines on construction sites. | |
| (only multi-core cables): Application as before, however in connection with parts of production systems including machine tools and manual mechanical devices, for example in connection with switch boards of a production machine. | ||
Storage as well as handling/transport
Cables that are not appropriate for outdoor use have to be stored inside in dry rooms. Some flexible cable constructions are especially prone to humidity. The cable ends that are stored outside or are expected to be stored in the open air have to be sealed in order to keep humidity outside.
During storage the maximum recommended storage temperature of 40 °C shall not be exceeded and the minimum laying or handling temperature has to be observed. Cable manufacturers are allowed to indicate a higher maximum storage temperature and lower minimum laying and handling temperature for certain construction types.
Wherever no minimum laying and handling temperature is indicated and no recommendation of the manufacturer is given, a min. temperature of 5 °C shall be assumed.
During the handling or transport any mechanical stress especially by vibration, impact, bending and torsion has to be minimized. In case that the temperature of the cable falls below the minimum laying temperature or exceeds the maximum storage temperature of 40 °C, additional provisions have to be taken if the probability of a cable deterioration increases. You can get additional advise from the cable manufacturer.
For cables on drums and wrapped ones appropriate provisions have to be taken to guarantee a safe handling and avoid any damage of the cable as well as any danger for other people.