The ratings and all specifications have to be considered before making the final selection, but the main points are the Switch size, the maximum operating current of the contact, the operating force, the actuator type, and the degree of protection.
First, choose a Switch size that can be mounted in the desired equipment. You can select from among Z-size General-purpose Basic Switches, V-size Miniature Basic Switches, S-size Subminiature Basic Switches, J-size Ultra Subminiature Basic Switches, and Special-purpose Basic Switches. Z-size General-purpose Basic Switches are available as an X-model direct-current switch with magnetic blowout, a DZ-model DPDT Basic Switch for controlling two independent circuits, and a TZ-model high-temperature Basic Switch for operation up to 400°C. V-size Miniature Basic Switches are available in a D2MC-model low-torque Basic Switch with rotary-action operation. Special-purpose Basic Switches are designed for specific applications, so they are limited to use, for example, as power switches for doors.
Next, select the maximum operating current of the contact based on the load to be switched. You can choose a model with a maximum value of 3 A to 21 A for large-capacity loads, a maximum value of 1 A for medium-capacity loads, or a maximum value of 0.1 A for microloads. This selection is necessary because contacts have appropriate current ranges. The maximum operating current of the contact is roughly proportional to the Switch size, so it is sometimes automatically determined by choosing the size.
The operating force and actuator type should be selected according to the mechanism and structure of the machine or device that will operate the actuator of the Basic Switch. There are two or more operating forces that you can choose from for each model. Some actuators are an integral part of the Basic Switch, and others, such as those in the Z-size General-purpose Basic Switches and V-size Miniature Basic Switches, are purchased separately. Note that the operating force is roughly proportional to the Switch size, so it is sometimes automatically determined by choosing the size. Also, larger-size Switches have a larger number of actuator types available.
Select the degree of protection by considering the environment in which the Basic Switch will be used. The degree of protection for most models is IP00, but there are also IP67 sealed models for the V-size Miniature Basic Switches, S-size Subminiature Basic Switches, and J-size Ultra Subminiature Basic Switches. The Z -model drip-proof degree of protection is equivalent to IP62.
When you have come up with an actual model number, confirm its ratings and other specifications to make your final decision.