How to choose household insurance and test switch?

Knife switch (Knife switch, referred to as KS), which uses a knife to switch on or off the connection between the power supply line and the load.

Above the knife, there is a fuse that can be melted at high temperature. When a short circuit occurs, the fuse can be blown to cut off the power supply.

The role of the knife switch

Knife switch is a kind of manual power distribution appliance. It is mainly used to isolate power or manually connect and disconnect AC and DC circuits. It can also be used to infrequently connect and disconnect loads below the rated current, such as small motors, electric furnaces, etc.

The biggest advantage of the knife switch is that there is an obvious disconnection point, and you can safely perform power outage maintenance by opening the knife switch.

Principles of Knife Switch Selection

The rated voltage of the knife switch must be consistent with the line circuit. The rated current is not less than the load circuit of the line.

For lighting loads, the rated current of the knife switch should be greater than 3 times the load current. In addition to operating purposes, the knife switch is mainly used for isolation.

How to choose household insurance and knife switch?

Calculate the total power of household appliances first, add up the power of all appliances including electric lights, and then divide by 220 to equal the current of A. For example, if it is 30A, then the current of buying a switch must be 40A-50A. For electrical appliances with high power, a sub-switch must be installed after the main switch. The current of the switch is selected according to the power and current of the electrical appliance it is connected to.

The main switch should be larger to prevent adding other electrical appliances in the future.

The knife switch has the advantages of the knife switch. The air switch is indeed more advanced, but it also has its shortcomings. The air switch is greatly affected by the environment. For example, if the air is humid, then it may oxidize and gradually break down, and this thing sometimes It will also malfunction. When the circuit has a short circuit and trips, if the short circuit below is not dealt with, the circuit breaker may be burnt out at the moment of closing. The knife switch will not be affected by the environment, and the short circuit will only burn the fuse. It will not cause damage to the knife switch.

The artile is reprinted from:https://www.amervolt.com/news/how-to-choose-household-insurance-and-test-switch