Connecting two industrial switches in parallel allows either switch to independently activate the same load, effectively creating an OR logic control.

How Parallel Switches Work

When two switches are connected in parallel, each switch provides an independent path for current to flow to the load. This means that closing either switch will complete the circuit and energize the connected device, such as a motor, solenoid, or indicator light . The voltage across each switch remains the same as the supply voltage, ensuring proper operation of the load .

Electrical Implications

• Current Distribution: Each parallel path reduces the total equivalent resistance, increasing the total current drawn from the power source. The power supply must be capable of handling this increased current .
• Voltage Consistency: All devices in parallel receive the full supply voltage, which is critical for industrial devices that require precise operating voltages .
• Load Activation: Parallel switches provide multiple ways to activate a single load, which is useful for safety, convenience, or redundancy in industrial control systems .

Practical Applications

• OR Logic Control: Parallel switches implement a digital OR function, where the load is activated if any one of the switches is closed .
• Multiple Start Points: Common in industrial machinery, allowing operators to start a motor or process from different locations.
• Redundancy and Safety: Ensures that if one switch fails, the other can still control the load.
• Load Switch Paralleling: In electronic circuits, paralleling load switch channels can reduce ON resistance, distribute power dissipation, and improve thermal performance .

Key Considerations

• Avoid placing multiple loads in series when using parallel switches, as this can reduce voltage to each device and impair operation .
• Ensure the power supply can handle the increased current demand from parallel paths .
• In PLC-controlled systems, parallel connections are less common due to potential overloading of input/output terminals; diodes or other protective measures may be required for inductive loads . In summary, connecting two industrial switches in parallel provides multiple independent control points for a single load, implements OR logic, and ensures consistent voltage to the load while increasing current demand, making it a practical solution for industrial control and safety applications.