Dutch to English Tech/Engineering Electronics / Elect Eng greenhouse automation

I'm currently translating an installation manual for a greenhouse environmental controller. The system includes switch boxes that are described as follows:

'Schakel paneel voor vermogensstap van motoren en andere apparaten.'

Any ideas how to translate 'vermogensstap' in this context?

I've currently translated this as follows (but I'm sure this is technically dodgy):

'Switch box for stepping up the output of motors and other equipment.'

Any input would be much appreciated!