Control cable selection guidelines

Date of publication: 16-05-2019 Update date: 24-03-2026 🕒 6 min read

Control cables are used to transfer data to machines and equipment operated in production process lines. As a result of constant development of automation systems and structural solutions control cable manufacturers face more and more stringent requirements.

Highlights at a glance

Control cables are used to transmit data and control signals between Automation devices.
Resistance to electromagnetic interference - the use of shielding is key when selecting cables.
The conductor material (usually copper and often tinned wire) determines mechanical strength and conductivity.
The insulation affects the cables' resistance to mechanical factors, chemical, UV, oils and fire.
The presence of halogens in the insulation is important in terms of fire safety.

How do control cables work?

The operation principle of control cables is based on control signal transfer or data transmission, i.e. transferring analogue or digital signals between a control device and an industrial automation system element. This requires a certain level of resistance and specific properties characterising the cables, so that they can be used as intended and ensure long-lasting safety and stability of operation.Thus, there are certain properties that must be taken into account while selecting the best solution. A broad scope of requirements related to the variety of working conditions or loads results in the fact that the choice of proper cables is not always a straightforward and obvious task.

How to select proper control cables?

Control cable properties to be taken into account:

Shielding – this term is closely related to electromagnetic interference that may be caused by industrial automation lines and equipment. However, it is not easy to image an industry in which cables are routed far away from equipment, as it increases the length of such cables and generates additional costs. Thus, a shield provides protection against interference and safeguards the signal. Obviously, unshielded cables are still used in certain industries. They are installed on those sites in which no interference occurs or where interference does not affect the quality of data transmitted. The most popular shielding materials include: aluminium foil, braids of tin plated copper wires or braids of galvanised steel wires. In order to enhance cable protection against interference, a few shields are often used simultaneously. In such cases, not only a cable itself is shielded, but its cores as well.
Cable core structure and material – control cables most often come with cord-like copper cores (sometimes additionally tin plated), as such a solution ensures considerable conductance. A proper choice of materials also ensures that a core is resistant to mechanical damage. Cables with nickel plated or silver plated cores are also available. This design results in higher strength and resistance to chemical processes.
Insulation material – is responsible for a number of properties and cable resistance. High-class insulating materials prevent malfunctions and extend the lifetime of the entire system. The external coat determines such properties as cable flammability, resistance to oil, chemical agents, UV radiation or mechanical damage, i.e. abrasion, cutting or crushing. Moreover, the insulating material determines the cable flexibility class and makes it possible to manufacture products for mobile applications. The most common insulating materials include: PVC (polyvinyl chloride), PUR (polyurethane), FRNC (Flame Retardant, Non Corrosive) or LSZH (Low Smoke Zero Halogen), i.e. a material which does not emit any harmful gases in contact with fire.

Halogen content – information regarding the halogen content is important in the context of fire protection. During combustion, halogen cables generate toxic gases, and halogen-free cables only emit slight amounts of non-toxic smoke.Selection of cable characteristics which are appropriate for operational conditions results in minimising any risk of malfunction and extending the lifetime of the entire system. New control cables by Alpha Wire (Pro-Met series) and Belden (MachFlex series) are a good response to the current market needs. Both series include flexible cabling in the locations where installation space is limited.

Parameter	Belden	Alpha Wire
Cable type	Control	Control
Cable type	MachFlex	Pro-Met
Insulation material	PVC	PVC
Rated voltage	300/500V 450/750V	300/500V
Insulation colour	Grey, transparent	Grey, transparent
Shielded	Depending on a series	Depending on a series
Operating temperature	Depending on a series	-30…70 deg. C
	-15…70 st. C ; -5…70 deg. C
Protective core	Yes	Depending on a series
Core marking	Black, numbered;	Black, numbered
	Colour marked, without repeated colours
Core type	Copper	Copper
Core cross-section	0,75…4mm²	0,5…1,5mm²
Core structure	Cord	Cord
Number of cords	3…15	2…12
Shield structure	Braided, tin plated copper wires;	Braided, tin plated copper wires
	braided, galvanised steel wires
Outer diameter	5,6…21,4mm	4,77…15,06mm
Packaging content	50m; 100m	50m; 100m
UV resistant	YES	YES
Flame retardant	YES	YES

Standard conductor sizes in control cables typically range from 0,5mm² to 4mm². Typical number of conductors ranges from 2 to even 15, which provides the flexibility to customize cables for specific industrial applications.

The basic types of control cables are YY (unshielded), CY (copper braid shielded) and SY (steel braid shielded). YY work well in environments without the risk of electromagnetic interference, CY are used in devices sensitive to interference, and SY in applications requiring high mechanical strength.

The selection of control cables is governed by international IEC standards and national electrical standards such as the NEC (National Electrical Code). These standards specify requirements for safety, fire resistance and material compatibility of cables.

Cables used in intralogistics must meet specific requirements for flexibility, durability and resistance to continuous motion, such as. in conveyor systems or automated warehouses. Cables are most often shielded cables, resistant to frequent bending.

Yes, many types of control cables are designed, to be resistant to the effects of chemicals. Insulating materials, such as PUR or PVC, provide resistance to oils, greases and solvents, making them ideal for chemical or petrochemical industries.

The term "control cable" refers to an assembly of insulated conductors in one common sheath, intended for the transmission of control signals. "Control cable" usually refers to a single insulated conductor, which can be used individually or in a set of several conductors.

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