What are Control Cables?
Control cables are electrical, interconnecting cables designed to send signals to control functional equipment. They are also designed in automation control for measurement and regulation. Due to the environment they are often used in, they are designed to be flexible enough for hassle-free routing and cabling. Depending on their construction properties, these flexible cables can be suitable for use under light, medium or high mechanical stresses. One key benefit of control cables is that they do not generate any electromagnetic interference (signal noise), which reduces the chance of your system or equipment experiencing a potentially hazardous malfunction. This also makes them ideal for sending low-voltage signals.
They’re used across many industries, especially in quality control, where precision is vital, and equipment must function properly every time including:
- Production centres.
- Assembly lines.
- Automated systems.
- Robotic technology.
- Power distribution.
What Does Current Regulation say about the Different Types of Control Cable?
Under the IET Wiring Regulations BS 7671 in the UK, YY, SY, and CY control cables are not currently recommended for use as part of a fixed installation stating, “For the purposes of ensuring compliance with BS 7671, the installation and use of non-standard cables, such as SY, CY and YY cables is discouraged.”
Differences Between Control and Power Cables:
Power and control cables are often mistaken for each other as they are both used as electrical cables. However, they serve different purposes for instance, power cables are specifically for sending energy from a source to equipment, whilst control cables are used to transmit signals that control equipment. Other key differences include:
- Application – Power cables are mainly used for power generation, distribution, transmission, transformation, and power supply lines. On the other hand, control cables are specifically designed to directly transmit electrical energy from the power distribution point to different electrical equipment and appliances.
- Cable Type – Power cables are used to transmit and distribute high-power electrical power in trunk lines of power systems while control cables offer superior resistance to interference (signal noise). This makes them ideal for sending low-voltage signals whilst power cables are capable of transferring higher energy.
- Voltage – Power cables usually have a higher voltage of 0.6/1KV or higher and can even reach up to 500KV. While Control cables usually operate at 300/450/600/750V.
- Construction – Control cables are typically in pairs, feature multiple cores, and have a robust sheathing that is also resistant to a variety of external factors like corrosion and temperature. On the other hand, the insulation and sheathing of power cables are generally thicker.
- Cores – Power cables have 1, 2, 3, 4, and 5 cores while control cables have a range of 2 to 61 cores, as they are often multi-cored.
Types of Control Cables:
CY Control Cables:
They are used as interconnecting cables for measuring, controlling or regulating control equipment. They are multicore-screened flexible cables with Polyethylene terephthalate (PETP) for electromagnetic interference free-transmission.
NYY-J Control Cables:
They can be used in industrial wiring installations in air or cable management systems embedded in cement and masonry. They are VDE-approved, solid conductor, black PVC jacketed and insulated, 600/1000-volt, control and power cables.
e.g. the NYY-J2.53C 2.5mm 3 Core PVC Power & Control Cable which is PVC insulated with a bedded and PVC tuff-sheathing, unscreened flexible control cable. It also features solid annealed copper conductors.
SY Control Cables:
The SY control cable is also known as an armoured flex, shielded flex, or armoured control cable. As it is a control cable, it is specifically designed to control and send signals to industrial equipment where there is a medium to high level of mechanical stress. This is supported by the flexible shielding and galvanised steel wire braid which offers mechanical protection and ensures no loss of flexibility. These are also typically used in control, signalling, protection, and measurement systems within industrial computer programming applications.
These can also be used for indoors, fixed installations, protected outdoors, drainage, water treatment and severe industrial environments.
In addition, whilst SY cables are ideal for industrial, domestic and commercial applications, they are not suitable for use outdoors as the braid may melt if exposed to heat from a short circuit. The PVC sheathing of SY is also not UV resistant so is liable to damage and decay over time if used outdoors.
SY Cable Structure:
- S = steel wire braid, and Y = PVC polymer.
- Copper conductor.
- 70-degrees Celsius working temperature.
- Most common voltage rating – 300/500V.
- PVC insulation and galvanised steel wire braiding.
- 0.5-10mm2 cross-sectional area.
- Multi-core – 2 to 61 cores.
As noted above, SY cables come in a wide variety of sizes and with varying numbers of cores.
2.5mm 3 Core SY cable
The SY2.53C 2.5mm 3 Core SY Steel Wire Control Braid Flexible Cable is an SY control cable with a 2.5mm² conductor size, 3 cores, a class 5 flexible copper conductor, and a black PVC outer sheath insulation material.
It can be used for indoor, fixed, protected outdoors, drainage, water treatment, and severe industrial applications thanks to its incredible flexibility and ability to withstand weather, oils, and mechanical or thermal stress. The SY cable also be used as an interconnecting cable for measuring, controlling, or regulating control equipment for production lines, conveyors, and computer units.
Overall, it is specifically designed for use in applications where it may be subjected to medium mechanical or thermal stress.
2.5mm 5 Core SY cable
The SY2.55C 2.5mm 5 Core SY Steel Wire Control Braid Flexible Cable is a black PVC outer sheathed and insulted SY control cable with a 2.5mm² cross sectional area/conductor size, 5 cores, a flexible, class 5 copper conductor. Thanks to its flexible construction, it can be used in flexible installations, where free movement is required without tensile stresses (or where light mechanical stress may occur) and without forced guidance systems.
The SY2.55C cable is used to control and regulate conveyors, instrumentation, assembly lines, production lines, and similar process automation equipment. It can also regulate air conditioning systems. This cable can also be used outdoors (but should be protected); however, it is best suited to dry or moist conditions indoors.
6mm 5 Core SY cable
The SY6.05C 6mm 5 Core SY Steel Wire Control Braid Flexible Cable is a 6mm² plain copper conductor constructed SY cable with a clear PVC, transparent outer sheathing insulation material. It is rather flexible making it ideal for indoor use where there are medium to high levels of mechanical stress. The flexible shield and galvanised steel wire braid also ensure a high level of mechanical protection and effective screening.
This makes the SY6.05C SY cable suitable for a wide range of applications including control applications, production lines, assembly lines, air conditioning systems etc. Unfortunately, as the sheathing is not UV-resistant, it is not suitable for use in direct sunlight as it can become damaged or decay over time. However, it can still be used in protected outdoor applications with the correct outer protection.
To summarise, the YY cable (unscreened, flexible control cable) can be used in indoor dry and wet conditions and is ideal for use in applications with light mechanical stress; the CY cable (screened, flexible control cable) is ideal for interference-free transmissions; whilst the SY cable (galvanised steel wire braid, PVC control cable) is most suited for applications which require more reliable mechanical protection as it is the toughest type of control cable.
Control cables are essentially designed to send signals (low-voltage electrical signals) to control the functioning of equipment. They are ideal for use in a wide range of automation and instrumentation industries and applications thanks to their high specifications and qualities.
Some of these include:
- High-quality construction with a variety of sheathing and braiding.
- High strength which makes it suitable for use in harsh environments.
- Lightweight.
- Flexible to suit any structure or environment.
- Safe & reliable.
- Can cut to length.
- Safe and reliable in production environments.
- Most importantly, low interference which allows for clear signal transmissions.
In general, without a control cable, it would not be possible to get electrical energy to your buildings or to power your appliances.