🔍 Key Concepts

• Understand the difference between a single-throw and a double-throw safety switch • Relate the number and arrangement of contact sets inside the box to the options on the external handle (e.g., ON‑OFF vs ON‑OFF‑ON). • Match an exterior view (handle positions/markings) with the correct interior mechanism (how many directions the blades can be thrown).

💭 Think About

• Looking closely at each exterior view, which one shows more than one ON position or clearly indicates two different source/load positions? • On the interior views, which one has switching parts arranged so the moving blades can connect to either of two different stationary contact sets? • If a switch can connect a circuit to either of two different sources, what must the internal layout of its contacts look like compared with a simple ON/OFF disconnect?

✅ Before You Answer

• Identify which exterior switch faceplate has three distinct positions (ON‑OFF‑ON or similar) instead of just ON and OFF. • For the interior views, look for two separate sets of terminals/contacts that a single operating handle could connect to, rather than just one line/load set with fuses. • Before choosing, be sure the pair you select could realistically be the same physical device seen from outside and then with the cover open (hinge/handle side should also make sense).