Moulded case circuit breakers are also commonly referred to as air switches. As the name implies, an air switch is a circuit breaker that uses air as an insulating medium. It can break normal load currents, which also depend on the good performance of the moulded case parts, and can also break a range of overload and short circuit currents. Unlike moulded case circuit breakers, vacuum circuit breakers, sulphur hexafluoride type circuit breakers and other types of circuit breakers, the main difference between these moulded case circuit breakers and moulded case circuit breakers is that the arc extinguishing medium and the insulating medium has been changed from ordinary air to other media, which we will have the opportunity to discuss later on. This topic focuses on the manual operation of ordinary circuit breakers with a rated voltage of 400V and a rated current of not more than 800A. I generally choose from the following three aspects.

1、Grade positioning: According to your budget situation, choose a suitable grade. Domestic, foreign or joint venture, domestic brands are more. If the budget is ample want to choose a better foreign brand

2, choose a product series: each enterprise brand company has improved their own products within the applicable tier division, procurement, we must distinguish, choose suitable for their own needs to use.

3. choose the grade of plastic shell parts, rated current, breaking capacity: here need expertise, try to invite professionals to match, to avoid selection errors, resulting in unnecessary losses.