The choice of cross-section of cables and wires is mandatory and very important point during installation and design of any circuit electrical installation. To correctly select the cross-section of the power wire, it is necessary to take into account the maximum current consumed by the load. Current values can be easily determined by knowing the rated power of consumers using the formula: I = P/220.
Knowing the total current of all consumers and taking into account the ratio of the permissible for the wire current load (open wiring) for wire cross-section:
- for copper wire 10 ampere on square millimeter,
- for aluminum 8 ampere per square millimeter, you can determine whether the wire you have is suitable or whether you need to use another one.
When performing hidden power wiring (in a tube or in a wall), the given values are reduced by multiplying by a correction factor of 0.8.
It should be noted that open power wiring is usually carried out with a wire with a cross-section of at least 4 square meters. mm based on sufficient mechanical strength.
The above ratios are easy to remember and provide sufficient accuracy for using wires. If you need to know with greater accuracy the long-term permissible current load for copper wires and cables, you can use the tables below.
The following table summarizes the data on power, current and cross-section of cable and conductor materials,
for calculations and selection of protective equipment, cable and conductor materials and electrical equipment.
Permissible continuous current for wires and cords
with rubber and polyvinyl chloride insulation with copper conductors
Permissible continuous current for wires with rubber
and polyvinyl chloride insulation with aluminum conductors
Permissible continuous current for wires with copper conductors
with rubber insulation in metal protective sheaths and cables
with copper conductors with rubber insulation in lead, polyvinyl chloride,
Nairite or rubber casing, armored and unarmored
Permissible continuous current for cables with aluminum conductors with rubber or plastic insulation
in lead, polyvinyl chloride and rubber casings, armored and non-armored
Note. Permissible continuous currents for four-core cables with plastic insulation for voltages up to 1 kV can be selected according to this table as for three-core cables, but with a coefficient of 0.92.
Pivot table
wire sections, current, power and load characteristics
The table shows data based on the PUE for selecting cross-sections of cable and wire products, as well as rated and maximum possible currents of circuit breakers for single-phase household loads most often used in everyday life
The smallest permissible cross-sections of cables and wires of electrical networks in residential buildings
Recommended cross-section power cable depending on power consumption:
- Copper, U = 220 V, single phase, two-wire cable
- Copper, U = 380 V, three phase, three-core cable
Load power depending on rated current
circuit breaker and cable section
The smallest cross-sections of current-carrying conductors of wires and cables in electrical wiring
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Core cross-section, mm 2 |
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Conductors |
aluminum |
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Cords for connecting household electrical receivers |
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Cables for connecting portable and mobile power receivers in industrial installations |
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Twisted two-core wires with stranded cores for stationary installation on rollers |
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Unprotected insulated wires for fixed indoor electrical wiring: |
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directly on the bases, on rollers, clicks and cables |
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on trays, in boxes (except for blind ones): |
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single-wire |
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stranded (flexible) |
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on insulators |
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Unprotected insulated wires in external electrical wiring: |
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on walls, structures or supports on insulators; |
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inputs from overhead line |
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under canopies on casters |
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Unprotected and protected insulated wires and cables in pipes, metal sleeves and blind boxes |
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Cables and protected insulated wires for stationary electrical wiring (without pipes, sleeves and blind boxes): |
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for conductors connected to screw terminals |
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for conductors connected by soldering: |
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single-wire |
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stranded (flexible) |
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Protected and unprotected wires and cables laid in closed channels or monolithically (in building structures or under plaster) |
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Conductor cross-sections and protective electrical safety measures in electrical installations up to 1000V
Click on the image to enlarge.
Selection of core cross-section for cable line SOUE
General Comparative characteristics cables for local network
| Cable type (10 Mbps = approx. 1 MB per second) |
Data transfer rate (megabits per second) | Max official segment length, m | Max unofficial segment length, m* | Possibility of restoration in case of damage / extension of length | Susceptibility to Interference | Price |
| twisted pair | ||||||
| Unshielded Twisted Pair | 100/10/1000 Mbit/s | 100/100/100 m | 150/300/100 m | good | Average | Low |
| Shielded twisted pair | 100/10/1000 Mbit/s | 100/100/100 m | 150/300/100 m | good | Low | Average |
| Field cable P-296 | 100/10 Mbit/s | -- | 300(500)/>500 m | good | Low | High |
| Four-wire telephone cable | 50/10 Mbit/s | -- | No more than 30 m | good | High | Very low |
| Coaxial cable | ||||||
| Thin coaxial cable | 10 Mbit/s | 185 m | 250(300) m | Poor Requires soldering | High | Low |
| Thick coaxial cable | 10 Mbit/s | 500 m | 600(700) | Poor Requires soldering | High | Average |
| Optical fiber | ||||||
| Singlemode optical fiber |
100-1000 Mbit |
Up to 100 km | -- | Specialist required equipment |
Absent | |
| Multimode optical fiber |
1-2 Gbit | Up to 550 m | -- | Specialist required equipment |
Absent | |
*- Data transmission over distances exceeding standards is possible when using high-quality components.
Characteristics of radio frequency cables type RK - RG
| Cable brand | Int. diameter | Diam. isolation, |
External conductor | Shell | Weight, kg/km |
Attenuation- nie, |
Recommended length up to video cameras, no more, m |
Recommended connector for connection video cameras |
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| math rial |
n*d, mm | d, mm | math rial |
d, mm/% | math rial |
d, mm | ||||||
| RK-75-1.5-11 | M | 1*0,24 | 0,24 | 1.5 PE | OM | 0,08/60% | PE | 2,4 | 8,4 | 0,32 | 50 | BNC RG-58 soldering |
| RK-75-2-11 | M | 1*0,37 | 0,37 | 2.2 PE | OM | 0,1/92% | PE | 3,3 | 16 | 0,22 | 300 | BNC RG-58 soldering |
| RK-75-2-11a | M | 1*0,37 | 0,37 | 2.2 PE | OM | 0,1/75% | PE | 3,3 | 14 | 0,23 | 200 | BNC RG-58 soldering |
| RK-75-2-13 | LM | 7*0,12 | 0,36 | 2.2 PE | AML | 0,1/92% | PE | 3,3 | 14,7 | 0,2 | 350 | BNC RG-58 soldering |
| RK-75-3-32 | M | 1*0,6 | 0,6 | 2.7 VPE | OM | 0,1/90% | PVC | 4,6 | 28,4 | 0,12 | 450 | BNC RG-58, RG-59 |
| RK-75-3.7-322a | M | 1*0,6 | 0,8 | 3.7 VPE | AL+OML | 0.1/lm65% | PVC | 6 | 37,3 | 0,085 | 600 | BNC RG-59 |
| RK-75-4-11 | M | 1*0,72 | 0,72 | 4.6 PE | OM | 0,15/92% | PE | 7±0.2 | 63 | 0,08 | 600 | BNC RG-6 soldering |
| RK-75-4-11a | M | 1*0,72 | 0,72 | 4.6 PE | OM | 0,15/75% | PE | 6.2±0.3 | 40 | 0,13 | 600 | BNC RG-6 soldering |
| RK-75-4-12 | M | 7*0,26 | 0,78 | 4.6 PE | OM | 0,15/92% | PE | 7±0.2 | 63 | 0,09 | 600 | BNC RG-6 soldering |
| RK-75-4-15 | M | 1*0,72 | 0.72/td> | 4.6 PE | OM | 0,15/92% | PVC | 7±0.2 | 72 | 0,08 | 600 | BNC RG-6 soldering |
| RK-75-4-16 | M | 7*0,26 | 0,78 | 4.6 PE | OM | 0,15/92% | PVC | 7±0.2 | 72 | 0,09 | 600 | BNC RG-6 soldering |
| RK-75-4,9-322a | M | 1*1,1 | 1,1 | 4.9 PE | AL+OML | 0.15/lm65% | PVC | 7,15 | 51 | 0,06 | 750 | BNC RG-6 |
| RK-75-9-12 | M | 1*1,35 | 1,35 | 9 PE | OM | 0,2/90% | PVC | 12.2±0.8 | 189 | 0,06 | Trunk | - |
| RK-75-9-13 | M | 1*1,35 | 1,35 | 9 PE | OM | 0,2/90% | PE | 12.2±0.8 | 169 | 0,06 | Trunk | - |
| RG-59 | M | 1*0,81 | 0,81 | 3.66 VPE | AL+OML | 0,15/67% | PVC, PE | 6 | 31 | 0,085 | 600 | BNC RG-59 |
| RG-6U | coolant | 1*1,02 | 1,02 | 4.4 VPE 4.7 VPE |
AL+OML AL+OML |
0,15/32% | PVC, PE PVC, PE |
7 | 36 | 0,09 | 650 | BNC RG-6 crimp |
| RG-11 | coolant | 1*1,63 | 1,63 | 7.11 VPE | AL+OML | /60% | PVC, PE | 10,3 | 166 | 0,05 | Trunk | - |
Electrical resistance of two copper conductors of a loop depending on the core diameter and length
Calculations using formulas more accurate than tables, and are necessary in cases where the tables do not contain the necessary data.
Ohm's law allows us to display characteristics electrical circuits through the interrelation of four main components:
- A - current (in Amps)
- V - voltage (in Volts)
- R - resistance (in Omaha)
- P - power (in Watts)
The relationship between these components is shown on the so-called “classical wheel” (see figure below)
This simple and easy to use diagram helps us understand the fundamental relationships in electrical circuits.
Wire resistance (in ohms) is calculated using the formula:
Where ?
- specific resistance (according to the table);
I
- wire length, m;
S
- cross-sectional area of the wire, mm 2;
d
- wire diameter, mm.
The length of the wire from these expressions is determined by the formulas:
The cross-sectional area of the wire is calculated using the formula
S = 0.785*d2
Resistance R2 at temperature t2 can be determined by the formula:
R2 = R1,
Where ?
- temperature coefficient of electrical resistance (from the table);
R 1
- resistance at a certain initial temperature t 1.
Typically, t 1 is taken to be 18°C, and all the tables above indicate the value of R 1 for t 1 = 18°C.
The permissible current strength at a given current density rate A/mm 2 is found from the formula:
I = 0.785*?*d2
Required diameter wires for a given current strength are determined by the formula:
If the load norm? = 2 a/mm 2, then the formula takes the form:
The melting current for thin wires with a diameter of up to 0.2 mm is calculated using the formula
Where d
- wire diameter, mm;
k
- constant coefficient equal to 0.034 for copper, 0.07 for nickel, 0.127 for iron.
The diameter of the wire from here will be:
d = k * Ipl + 0.005
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Material |
Resistivity, Ohm x mm2 |
Specific gravity, g/cm3 |
Temperature coefficient of electrical resistance |
Melting point, °C |
Maximum working temperature; °C |
| Copper | |||||
| Aluminum | |||||
| Iron | |||||
| Steel | |||||
| Nikelin | |||||
| Constantan | |||||
| Manganin | |||||
| Nichrome |
Testing internal power wiring
Before energizing electrical installations and putting them into permanent operation, it is necessary to check whether the installation work and whether the wiring is ready for normal operation.
To do this, carry out an external inspection of the mounted installation, check the correctness of the connection diagrams, and then evaluate the condition of the electrical insulation by measuring its resistance with a megger.
The megohmmeter consists of a ratiometer and a direct current generator with a manual drive or with a rectifier for connecting the device to the network.
When measuring insulation resistance, the device is turned on in a de-energized circuit and the generator handle is rotated, bringing the rotation speed to the nominal speed, i.e. 120 rpm. Without reducing the indicated frequency, the handle is rotated until the instrument needle stops moving along the scale. The arrow shows on a scale the insulation resistance of the circuit connected in series with the device.
The insulation resistance of circuits and distribution boards (for each section) with all devices and instruments connected to the network is measured with a megger 500 …1000 V. The insulation resistance must be at least 500 kOhm.
Insulation resistance of electric motors measured with a megger 1000 Volt, must be no lower 0.5 MOhm.
In lighting electrical wiring, the insulation resistance is determined with a megohmmeter. 1000 Volt, before screwing in the lamps and connecting the neutral wire to the lamp body. At each section, the insulation resistance is measured between the wires and relative to the ground. It should be no lower 0.5 MOhm.
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To ensure smooth operation fire alarm The sensors are connected to warning devices and the dispatcher's console via wires (loops). The cables also transmit control messages, optical signal, etc. The types of fire alarm loops are divided according to their structure; the requirements for them are specified in SNiP and Federal Law No. 123.
Requirements for fire alarm wires
All basic requirements for fire alarm loops are to ensure the system is operational in the event of a fire for the required time. Ideally, the cable should have the same degree of fire resistance as the room.The terminal device of the loop is provided with structural additional or any other fire protection.
According to the Federal Law, cable standards are regulated by decree dated July 10, 2012. In particular it is stated:
- The resistance of the fire alarm loop must withstand exposure to an open flame for a specified amount of time. The functionality of the warning and alarm systems is maintained in full until employees and visitors leave the building.
- It will help you choose cables that comply with GOST. The designation of fire alarm loops is regulated by the Federal Law, therefore the wire marking must be present on the winding.
- Horizontal and vertical are protected by non-combustible structures and fire protection. Standards for laying fire alarm cables require the use of a wire with a heat-resistant winding. Inside the ceiling walls, voids and niches, installation is carried out in a corrugated pipe. When laying open fire alarms, non-flammable wire is used.
- The passage of cable lines through walls requires mandatory treatment fire retardant compounds. During the work, sealing of joints and others is carried out. The method of laying through the walls is determined taking into account technical characteristics building, its fire hazard. The necessity of laying in boxes is determined by the degree of fire hazard of the room.
- Laying with other cables is permitted provided that there is a thermally insulating winding.
- Fire alarm maintenance must be carried out by a specialist, a representative of the company that installs the warning systems.
To determine the location of a fire, it is necessary that all systems are in in working condition. For fire alarms, a cable resistant to open fire must be used. The fire resistance limit is calculated according to the PPB requirements for load-bearing structures in room.
Types of loops for fire alarms
Selection of cable cross-section, maximum length PS loop and many other aspects are calculated after selecting the sensor connection diagram. There are several basic ways to accomplish this task:- Threshold systems with radial loop. One control device, a monoblock, is able to service no more than ten lines and sensors. Increased capabilities are achieved by installing another loop control unit. The system received its name due to the operating principle used. Each sensor has its own sensitivity threshold. When it is reached, an alert is triggered.
The disadvantage of the threshold system is a large number of false signals. Laying together with other cables only aggravates the situation. Another disadvantage is the impossibility precise definition fire places. The system only notifies about a line break, so you have to check the entire radial type loop.
The advantage of the solution is the low cost of equipment and installation work. - Threshold structures with modular loop. Practically no different from the previous scheme. The difference is that the module used can control the operation of many lines simultaneously. The loop parameters allow you to duplicate the alert signal by connecting two-threshold structures.
- Addressable analog lines. Control over the system is exercised by the module to which it is connected ring loop. The difference between an addressable analog device is that the sensor itself does not make a decision about the presence of a fire, but simply transmits necessary information to the remote control.
A system with a ring construction of loops allows you to filter out unnecessary information. The signal is duplicated and transmitted to the control panel. The analysis makes it possible to distinguish fire cases from cable breaks and other loop faults. Transit installation allows the use of cable lengths up to 2000 m. - Combined systems. To output a signal to the dispatcher, both threshold and analog equipment are used. Modern signaling, which takes into account all the shortcomings of previous lines. The loop troubleshooting algorithm is simplified thanks to the use of a ring circuit.
Combined systems can be used both indoors and outdoors. In the second case, a shielded outdoor cable is used.
For some categories of premises, PPB establish certain restrictions on loops. Installation of exclusively non-flammable wire, inadmissibility hidden wiring, installation in a cable tray - these and other restrictions are described in SNiP 3.05.06-85 and VSN 116-87.
What cable is needed for PS?
The brand of wire for installation is determined by the fire hazard category of the building and installed system alerts. The decision to use thermal cables and other types of materials is made during the development of design documentation. When choosing a cable, the following indicators play an important role:
- Section calculation. Insufficient power and throughput can lead to inaccurate sensor readings. When threshold systems low-current cable can cause constant false alarms.
- Sufficient cable protection. In addition to thermal insulation and the presence of a non-flammable winding, it may be necessary to reduce the sensitivity of the loop. In a normal situation, you can immediately use a protected wire. But if, due to oversight or other reasons, the substation malfunctions due to the sensitivity of the cable, the insulation resistance of the loop is measured.
- Marking. The fire resistance limit of the cables, the presence of cable shielding and other indicators must be indicated on the wire winding. The rules for marking cable lines also require indicating the coefficient of smoke and flammability.
- NG - non-flammable - has a classification according to fire resistance from A to D.
- LS – recommended for installation in hazardous areas, as well as in a group tray. They do not emit harmful fumes during combustion.
- HF – when burning, they do not emit substances with high corrosive properties. Laying in a cable tray together with other alarm wires is allowed.
The standards for laying loops depend on the alarm system used and the current requirements of the safety regulations. The list of cables acceptable for use is given in SNiP and PUE. Violations of the recommendations lead to a malfunction of the PS.
If the cable does not comply with the standards, upon discovery of this, the inspector of the Ministry of Emergency Situations will write an explanatory note and bring to administrative responsibility indicating the timing of replacement of existing cables.
Methods for laying PS cables
Installation and maintenance of the alarm system is described in VSN 116-87, additional requirements are found in SNiP 3.05.06-85. Among all the instructions, the following can be highlighted:
Fire alarm cable
5 (100%) 1 voteIf a fire occurs in various types buildings, the fire alarm is activated (if installed). Next, fire extinguishing devices are automatically turned on. In this case, the quality of the elements that provide energy supply for extinguishing and life support devices in the premises plays an important role.
First of all, we are talking about such complexes as:
- main and spare power supply lines for pumps;
- mechanisms to prevent unauthorized access to protected locations;
- electric lighting;
- ventilation systems;
- emergency stations to turn off the gas supply;
- water supply.
Today, the role of fire alarms is appreciated
Requirements for fire alarm cables
All technical requirements for the parameters of fire-resistant wire are set out in Law No. 123-FZ of July 22, 2008. Russian Federation. The document lists the characteristics that ensure the strength of energy transmission lines when exposed to hazardous factors, for example, during firefighting various objects. The required parameters of the lines used provide protection in emergency situations, ensuring the preservation of life and health of people, as well as the property of protected buildings.
IN technical requirements The following parameters are described for fire-resistant wires:
- cable characteristics;
- requirements for horizontal and vertical channels of cable lines;
- properties of connectors.
Electrical capacity of wires for fire and burglar alarm, as well as the level of signal attenuation in them at frequencies up to 1 kHz must comply with established standards.
There are the following types of electrical cables:
- The frost-resistant version can be used at temperatures down to -70˚С.
- The heat-resistant type of wires is designed for use in enclosed spaces, as well as in tubular or box-shaped cable channels. It is designed for operation in the operating temperature range from -40 to + 105 degrees, provided that the physical and electrically conductive qualities remain unchanged.
- Basic version, intended for use in conditions of operating temperatures ranging from -40 to + 70˚С.
It is necessary to pay due attention to the selection of cables, because it is through them that an important alarm signal is transmitted
Wire wiring fire alarm With throughput up to 60 V can be laid together with the following lines:
- warning and telecommunications;
- power supply for automatic alarm devices.
This type of wire must have only copper conductors. Intrinsically safe lines are also required to comply with parameters that do not violate the technical conditions listed in the above law.
Fire hazard classes of protected wire
When laying lines that are part of the fire alarm system, you can only use marked cables, where the flammability class will be indicated.
They have the following letter markings:
- NG- This is a non-flammable wire. It can be classified according to its fire resistance. The letters A to D are used for this.
- HF– these are cables that, when ignited, do not release elements that have increased corrosion characteristics. They can be laid next to the rest of the alarm system wires.
- L.S.- these are lines that are usually drawn in areas that have high level explosion hazard. They don't highlight harmful substances during the combustion process and can be laid in a group tray.
Cable products are usually divided into categories according to the method of execution
Types of fire-resistant and fire-resistant cable
Non-flammable cable for fire alarm systems, among other things, used for power supply important devices, used in fire extinguishing, and control panels.
Today, non-flammable wires of several standardized types are used:
- FRLS- This is an energy conductor with a rubber silicone insulating winding equipped with a polyvinyl chloride coating. Such a current transmission product can be used in conditions high temperatures. It is protected from combustion, and its shell does not emit smoke. Evaporating elements released into the air during combustion are characterized by the absence of toxic and corrosive properties.
- FRHF is a thermal cable that has a sheath made of halogen-free, non-flammable polymer material. When heated, the covering composite does not release harmful components into the atmosphere. The fire resistance of such wires falls into the classifications FE180/E30 and FE180/E90.
Lines for security and fire alarm systems must meet the same requirements.
The Russian market of fire protection products has a wide range of different cables. Based on the required qualities, you can easily select a wire that will be used in alarm systems.
The first and, perhaps, main thing is fire resistance - the ability of a cable to transmit a signal when exposed to open fire.
4.33. The selection of wires and cables for fire alarm loops and connecting lines should be made in accordance with the PUE, taking into account the requirements of this section and technical documentation for specific types of plant equipment.
4.34. Fire alarm loops and connecting lines must be made with the condition of ensuring automatic monitoring of their integrity along their entire length.
This requirement does not apply to equipment whose operating principle does not allow automatic control.
4 . 36. Fire alarm loops should be made with independent wires and cables with copper conductors.
Fire alarm loops with voltages up to 60 V should be made with communication wires.
4.36. Connecting lines with voltages up to 60 V must be made using telephone cables with copper conductors of an integrated communication network, provided that communication channels are allocated.
If it is impossible to use an integrated communication network, it is allowed to make connecting lines with independent wires and communication cables with copper conductors.
4.37. The diameter of the copper core of wires and communication cables must be at least 0.4 mm.
4.38. The power supply circuits for fire alarm stations and control panels, as well as the control circuits for automatic fire extinguishing installations, should be carried out using separate wires and cables. It is not allowed to lay them in transit through premises controlled by automatic fire detectors, with the exception of laying heat-resistant wires and cables or in voids building structures with zero fire spread limit.
4.39. The laying of wires and cables should be carried out in accordance with PUE, SNiP III-33-76*, technological design standards VNTP 116-80 of the USSR Ministry of Communications "Wired communications. Linear cable structures" and taking into account the requirements of this section.
4.40. It is not allowed to lay circuits with voltages up to 60 V together with circuits with voltages over 60 V in one pipe, one sleeve, box, bundle, closed channel of a building structure or on one tray.
The joint laying of these chains is allowed only in different compartments of boxes and trays. having continuous longitudinal partitions with a fire resistance limit of at least 0.25 hours made of fireproof material.
4.41. Wires and cables of intrinsically safe circuits should be laid in accordance with the PUE and technical specifications for fire alarm devices.
4.42. In case of parallel open installation, the distances between the wires and cables of fire alarm loops and connecting lines with power and lighting wires must be at least 0.5 m.
If it is necessary to lay these wires and cables at a distance of less than 0.5 m from power and lighting wires, they must be protected from interference.
It is allowed to reduce the distance to 0.25 m from wires and cables of fire alarm loops and connecting lines without interference protection to single lighting wires and control cables.
4.43. In rooms where electromagnetic fields and interference exceed the level established by GOST 23511-79, fire alarm loops and connecting lines must be protected from interference.
4.44. If it is necessary to protect loops and connecting lines from electromagnetic interference, shielded or unshielded wires and cables should be used, laid in metal pipes, sleeves, boxes, etc. In this case, the shielding elements must be grounded.
4.45. External wiring of fire alarm installations is not allowed to be carried out using overhead lines, with the exception of wiring in installations With single-loop receiving and control devices in rural areas, as well as registering on cables between buildings when it is impossible to lay underground routes.
4.46. Mutually redundant cable lines supplying electricity to fire alarm installations should be laid along different routes, eliminating the possibility of simultaneous loss of mutually redundant cable lines during a fire. Laying them in one cable structure is prohibited.
The joint laying of the specified cable lines is allowed, provided that one of them is laid in a box (channel) made of fireproof materials with a fire resistance rating of at least 0.75 hours.
4.47. Connecting pins must have a reserve margin of 20% for cable conductors and telephone box terminals, respectively.
The principle of operation of fire and security alarm systems is to monitor attempts of unauthorized entry by unauthorized persons or the appearance of fire points with subsequent transmission of a signal to control and warning units. The connection of the main components (control panel, control panel, sensors, power supply, etc.) is provided by wires and cables for security and fire alarms. The products contain a copper core made of one or more wires; the insulating coating can be made of PVC plastic ( security systems) or plasticizer ( fire protection systems). Some types have an aluminum foil screen located under the insulating sheath: this element allows the wire to be used at a point with high degree interference during the transmission of information, ensures high reliability of the system both in outdoor conditions during a thunderstorm, and protection from electromagnetic interference.
The modern market offers products for installation in buildings, underground structures, door/window openings, ventilation ducts, outdoor conditions. The choice is made based on the compliance of the technical characteristics of the wire with the purposes of operation.
Basic requirements for a security alarm cable
Products for fire systems must meet the following criteria:
- Fire resistance, ability to work in case of fire
- Low smoke emission
- No halogen particles in the composition
- Copper core diameter from 0.5 mm (when working indoors)
Requirements for wires for security alarms:
- High strength to mechanical stress, influence of moisture, chemicals (especially important when laying wires in open areas)
- Fire resistance (when installed in a hazardous area)
- No toxic substances inside the insulating layer
- Section diameter from 0.22 mm
Cable production Russian production must meet the requirements of GOST R 53315-2009. The marking contains the type of design with the corresponding index (ng-FRLS or ng-FRHF), fire safety class. Foreign products have the designations H and E180 in the marking: this means the use of a polymer composition for core insulation, which is not subject to ignition and corresponds to a fire resistance class with a period of 180 minutes. A high-quality cable for fire alarm systems has a certificate containing information on compliance with international technical standards fire resistance, insensitivity to the spread of fire, the amount of volatile substances released by halogen acids, changes in smoke density.
Types of wires and cables used
| Cable marking | Core cross-section | Application area |
| SHVVP | 2x0.5mm 2 2x0.75mm 2 |
Power cable for connecting electrical appliances to a 220V network |
| NYM | 3x1.5mm 2 or more | Power cable for connecting electrical appliances to a network with a supply voltage of up to 660V |
| KSPV, KSPEV | 4x0.4mm 2 8x0.4mm 2 4x0.5mm 2 8x0.5mm 2 |
A cable with single-wire copper conductors is intended for laying security alarm loops. With and without shielding. |
| KVVGng-FRLS and others | 2x0.5mm 2 2x0.75mm 2 |
Fire-resistant cable intended for laying warning systems and fire automatic control systems |
| KPSVV and others | 2x0.5mm 2 2x0.75mm 2 |
Fire-resistant cable intended for laying fire alarm systems |
