Introduction: Power and Control Cable
KVVG and VVG are two copper cables that look similar but solve opposite tasks. VVG is a power cable, created for transmitting electricity to sockets, lighting, and machine tools. KVVG is a control cable; its element is circuits of control, alarm and automation, where currents are measured in milliamperes and the voltage rarely exceeds 660 volts. Confusion between them arises due to the common PVC insulation and similar marking, however, GOST standards and design differences separate them into different corners of electrical installation.
Power VVG is standardized according to GOST 31996, control KVVG — according to GOST 26411-85. The conductors of the first one start from 1.5 mm² and go up to 240 mm², while the typical range of the second is from 0.75 to 2.5 mm² with a large number of conductors. The letter “K” at the beginning of the designation precisely indicates the control purpose. A detailed comparison of VVG characteristics with other conductors is given in the review about VVG, and the features of choosing control types are analyzed in the article about KVVG.
Comparative Table of KVVG and VVG
| Parameter | KVVG | VVG |
| Type | Control cable | Power cable |
| GOST | 26411-85 | 31996-2012 |
| Number of conductors | 2–37 | 1–5 |
| Conductor cross-section, mm² | 0.75; 1.0; 1.5; 2.5 | 1.5–240 |
| Conductor material | Solid or stranded copper | Copper, aluminium (AVVG), solid or stranded |
| Rated voltage | 660 V or 1000 V AC | 660 V or 1000 V AC |
| Insulation and sheath | PVC compound, ng, ng-LS versions | PVC compound, ng, ng-LS, FRLS versions |
| Flexibility | Moderate, conductor class 1 or 2 | Moderate, conductor class 1 or 2; flexible versions — class 5 |
| Permissible continuous conductor temperature | 70 °C | 70 °C |
| Bending radius | Not less than 6 outer diameters | 7.5–10 diameters depending on the cross-section |
| Main application | Control, alarm, automation, telemetry circuits | Distribution and supply networks, equipment connection |
| Cost relative to VVG | Lower for the same cross-section, but higher due to the number of conductors | Basic price level for power copper cables |
Purpose and Application Logic
VVG transfers energy: from the service entrance panel to distribution boxes, from the circuit breaker to the boiler, from the substation to the workshop. Its task is to pass a current of tens and hundreds of amperes with minimal heating and losses. The cross-section is calculated based on the power of consumers; for a typical apartment it is 1.5 mm² for lighting and 2.5 mm² for sockets; for a three-phase service entrance — 10–16 mm². KVVG never powers a socket or a stove. Its destiny is to transmit a signal from a sensor to a controller, connect a button to a starter, lay communication between automation cabinets. Currents here rarely exceed 5–10 A, and the main enemy is electromagnetic interference, from which the control cable is not protected unless the shielded analogue KVVGE is chosen.
Confusion arises when an electrician, out of habit, takes VVG for connecting limit switches or thermocouples. It will work, but with reservations: the power cable is stiffer, takes up more space in the terminal block, costs more at small cross-sections, and most importantly — is not designed for frequent bending and vibrations typical of machines. And vice versa, KVVG is unacceptable in power circuits: its thin conductors are not rated for high currents, and the insulation under overload softens faster than that of VVG. The catalogue of power wires is presented in the VVG cable section, control ones — KVVG cable.
Design: Conductors, Insulation, Sheath
Both types have PVC conductor insulation and an overall PVC sheath. The difference lies in the number and cross-section of the conductors. VVG is produced with 1–5 conductors of a large cross-section; the shape can be round or flat. KVVG is multi-conductor, from 2 to 37 conductors, all thin, with a cross-section of no more than 2.5 mm². It is precisely the large number of conductors that makes it possible to connect dozens of sensors and signal lamps with one compact bundle. The marking contains the letter “K” at the beginning, and after a hyphen, fire safety indices may follow: ng, ng-LS, which stands for non-flammable with low smoke emission. VVG’s fire-safe versions are just as diverse: VVGng, VVGng-LS, VVGng-FRLS.
Stranded conductors are found in both families. Soft stranded VVG is marked with an additional letter “G” at the end or a mention of flexibility class 5. KVVG is usually made with solid conductors, which simplifies termination in terminals, but there are also flexible versions. The bending radius of KVVG is smaller — 6 diameters, while VVG’s is 7.5–10, therefore the control cable is easier to lay in a cramped cabinet. The outer dimensions and weight per metre depend on the cross-section and the number of conductors; for KVVG 10×1.5, the diameter will be about 15 mm, weight — around 350 g/m. For VVG 5×1.5, the diameter is slightly smaller, weight about 200 g/m.
Electrical Parameters and Permissible Loads
The continuous permissible current for VVG with copper conductors is: 1.5 mm² — 19 A, 2.5 mm² — 27 A, 4 mm² — 35 A when laid in air. This allows transmitting up to 4–6 kW of power through a single 2.5 mm² conductor. Control KVVG has the same current values for similar cross-sections — PVC insulation operates at 70 °C regardless of the purpose. However, using KVVG at 25 A is unwise: its conductors are thinner, there are more of them, and overheating of one leads to an avalanche heating of the entire bundle. The normative documentation directly prohibits the use of control cables in power circuits, except in cases where the current does not exceed a few amperes.
The operating voltage for both types is 660 or 1000 V AC. For 220 V control circuits, KVVG is suitable without restrictions. Neither VVG nor KVVG is suitable for outdoor use without UV protection — the PVC sheath degrades. For underground installation, armoured VBbShv is used or VVG is laid in an HDPE pipe. KVVG is not used in the ground. The requirements for certificates are standard: VVG — according to GOST 31996, KVVG — according to GOST 26411. The passport for the coil contains the actual conductor diameters, insulation resistance and the manufacturing length.
When to Choose KVVG
- Control and automation circuits: connection of contactors, relays, push-button posts, starters.
- Alarm, dispatching, telemetry systems, where many pairs are required in one cable.
- Internal connections in panels and consoles — when one wire must gather dozens of signals.
- Connection of sensors with low currents: resistance thermometers, limit switches, position sensors.
- Facilities where compactness is important and the budget does not allow laying many individual wires.
When to Choose VVG
- Power supply of socket and lighting groups in residential, office and industrial buildings.
- Connection of powerful consumers: water heaters, stoves, air conditioners, machine tools.
- Distribution networks from floor panels to end points.
- Laying in the ground in a protective pipe, in trays, cable ducts — wherever energy transfer is needed.
- Wooden houses and fire-hazardous premises: VVGng-LS is mandatory.
Typical Mistakes in Selection and Installation
- Replacing VVG with control KVVG in a socket network. The thin conductors overheat, the insulation melts, short circuit.
- Laying VVG in control circuits with a large number of signals. This results in a bulky bundle of several cables; installation is more expensive and complex.
- Using KVVG without taking into account the minimum bending radius. Although it is smaller than that of VVG, a sharp bend still tears the insulation.
- Connecting stranded KVVG in a screw terminal without a ferrule. The wires fray, the contact heats up.
- Buying a cable without a certificate: ordinary PVC, which smokes and burns, is sold under the guise of VVGng-LS.
- Laying KVVG outdoors without protection. The PVC sheath cracks in the sun within a season.
Frequently Asked Questions
What is the difference between KVVG and VVG?
KVVG is control, VVG is power. The first has many thin conductors for signals, the second has a small number of large cross-section conductors for energy transfer. Different GOST standards and areas of application.
Can KVVG be used for sockets?
No, its cross-section and design are not rated for the currents of domestic sockets. VVG with a cross-section of 2.5 mm² is intended for sockets.
How is the marking KVVGng-LS deciphered?
K — control, V — PVC insulation, V — PVC sheath, G — bare (without armour), ng — non-flammable, LS — low smoke emission.
What power can KVVG 2.5 mm² withstand?
The same as VVG 2.5 mm² — about 5–6 kW per conductor. But KVVG must not be used in power circuits according to the standards.
What is the difference between KVVG and VVGng?
VVGng is power non-flammable, KVVGng is control non-flammable. The difference is in the cross-section of the conductors, the number of conductors and the purpose.
Conclusion
KVVG and VVG are two copper instruments, confusion between which can be costly. Power VVG delivers energy, control KVVG transmits information. Each has its own GOST, dimensional range and area of trouble-free operation. An installer who understands this difference will not put a thin control bundle on a socket and will not pull a rigid power cable to a dozen sensors. The correct choice between KVVG and VVG is the key to the safe and predictable operation of an electrical installation for decades.
