🔍 Key Concepts

• Electrical arcing when contacts open or close • Effect of speed and pressure of contact movement on heat and pitting • Difference between what happens when contacts open vs close under load

💭 Think About

• When is an electrical arc more likely to be long-lasting and destructive: during a fast, firm contact action or a slow, gentle one? • How does breaking current under load affect the surface of contacts compared to just making the connection? • Which condition would most increase heat at the contact point and tend to weld metal surfaces together?

✅ Before You Answer

• Identify which options involve slow vs. fast movement of the contacts • Determine which action is happening under load (current flowing) and whether the load is being made or broken • Consider which situation would create sustained arcing and heat right at the contact faces