Why are relay contacts normally used to carry current to a solenoid?

• A. Relay contacts are designed to carry higher currents than pushbuttons
• B. They provide faster response times
• C. They are cheaper
• D. They have lower contact resistance

Answer: (A)

When energizing a solenoid you need to switch a fairly large current, and you’re dealing with an inductive load that can cause voltage spikes. Pushbuttons are meant as light, user-operated switches and are often rated for only small currents; using them directly to power a solenoid can heat, wear, or weld the contacts. Relay contacts, by contrast, are specifically built to handle higher current loads and to switch inductive loads safely. They act as a bridge between a low-current control circuit and the high-current load, allowing a small control signal to energize the solenoid without stressing the control device. This isolation and current-handling capability is why relays are normally used to carry current to a solenoid. While other factors like speed, cost, or contact resistance exist, the essential reason is the higher current rating and robustness of relay contacts for switching the solenoid.