What is Derating? Why is this necessary? It is the same for all drives, motors, and wires

What is Derating?

The current currying of cables will vary according to the place of installation temperature (location of site), kind of run (duct, trench, buried, etc.), the number of trays, depth of trench, and distance between cables. Derating occurs when the actual present currying capacity of a cable is less than the current currying capacity (as specified in the cable catalogue).

Derating is an engineering method that may significantly enhance reliability. Electrical & electronic components loses some of their reliability when they are forced to operate under extreme stress.

are the primary stress factors.

Derating is the process of operating a component (or) device at a capacity (or) rating that is less than its maximum capability. This is done to assure the component’s dependability, safety, and longevity, especially in demanding (or) forceful settings. Derating is necessary because working components towards their maximum limits for lengthy periods of time can result in overheating, decreased efficiency, increased wear & tear, and, in extreme cases, failure.

Derating does not apply to all sorts of components, such as


  • Environmental circumstances,
  • Duty cycle,
  • Ambient temperature,
  • Installation layout, and
  • Intended usage

all influence derating factors for each component.

Let’s observe how each of these elements is affected by derating:

1). Drives

Derating is required in the case of electronic drives (such variable frequency drives, or VFD’s), as these components generate heat while in use. The performance & lifespan of electronic drive components can be impacted by high temperatures.

Derating recommendations might suggest lowering the drives maximum load carrying capability or adding more cooling techniques to keep it working at a safe temperature.

2). Motors

Depending on variables like ambient temperature, duty cycle, & altitude, motors may need to be derated. Continuously operating a motor close to its maximum load capacity might cause overheating and early failure.

Derating helps in maintaining the motor’s working temperature within safe limits, promoting longer life and dependable performance.

3). Cables

The conductor resistance & the current-carrying capacity effects cause cables to get overheated, hence cables are graded to avoid this from occurring.

  • Overheating,
  • Deterioration of the insulation, and
  • Potential fire risks

can result from current levels that are greater than the wires can withstand.

Derating factors for cables include things like the surrounding temperature, the way they are installed, and how many cables are bunched together.

Necessity of Derating in Industry

Various manufacturers and systems may have various derating values for each component. To find the right derating factors for particular applications, designers and engineers must refer to the manufacturer’s datasheets, instructions, or industry standards. By decreasing the possibility of unanticipated breakdowns and downtime, according to derating standards assures the dependable and safe functioning of electrical & electronic devices.