What is the difference between a control cable and a motor cable?

igu-blog-adm | 22. April 2020

There are different types of cables which are manufactured for very different applications. In one of our last articles we took a closer look at the servo cable and the motor cable.

Today we clarify the question: what is the difference between a control cable and a motor cable?

What is the difference between a control cable and a motor cable?

The main difference between a control and a motor cable lies in the voltage class. While a control cable usually has a voltage class of 300V/500V, the voltage class of a motor cable is 600V/1000V.

The reason for this lies in the strength of the core insulation. This is stronger with a motor cable than with a control cable despite the same conductor cross section. As a result, the core insulation achieves a higher capacity, which in turn gives the cable the higher voltage class.

Furthermore, motor cables are only available from a conductor cross section of 0.75mm². A control cable on the other hand is already available with a cross section of 0.25mm². Differences can also be found in the upper limit of the cross section. In most cases, control cables are only offered up to a cross-section of 6mm². However, motor cables with a cross section of 50mm² and more are not uncommon in larger systems.

Another difference can be found in the number of cores. While motor cables are typically offered with four cores (L1, L2, L3, PE) or as single core, a control cable often consists of many more cores. The requirement for a motor cable is always the same. Namely the supply of a motor with electricity. Therefore they always have the same core combination: 3 phases and a protective conductor. Control systems, on the other hand, are often much more complex and therefore require more cores to transmit the various signals to the appropriate locations.

What does the data 300V/500V or 600V/1000V mean?

These specifications describe the permissible nominal voltage of a cable, specified in volts. The first value is the maximum permissible effective value between conductor and protective conductor. The second value is the maximum permissible effective value between two conductors of the same voltage system, i.e. L1-L2.

What are the typical applications of the two types of cable?

The classic control cable is often found in the same installations as the motor cable. However, they have a different function. Control cables are used for signal transmission and as energy supply for smaller applications.

Motor cables, as the name suggests, are used wherever a lot of energy (current & voltage) has to be supplied to a consumer, such as motors. An example of this is the motor of a harbour crane.

Since in many areas a voltage class of 300/500V is completely sufficient, the control cable is used more often. If a motor is supplied via a standard household socket, there is no reason why a control cable should not be used instead of a motor cable. This is possible because the motor is only operated at the nominal voltage of 230V/400V.

The motor cable with its voltage class of 600/1000V is required if the motor speed is controlled by a frequency converter and voltage peaks occur due to the pulse width modulation.

Would it not be easier to produce all cables with a higher voltage class?

This step would simplify some things. With the result that a cable can do both. However, motor cables are more expensive and thicker than control cables due to the more complex core insulation. They are often not needed.

Since in many areas a voltage class of 300V/500V is completely sufficient, both cable types are justified. If, for example, a motor is operated with a nominal voltage of 230V, there is no reason why a control cable cannot be used instead of a motor cable for the power supply. This would be the more cost-effective alternative.

Conclusion

Although control and motor cables show some parallels, they are used for different purposes. In addition, the use in different voltage classes and also the varying cross section show the necessity of both cable types on the market.

Both cable types are available with and without shielding.

Do you also want to save costs? Reduce costs and improve your technology with our price check. We would also be pleased to advise you personally and find the right cable for your application.