There are some household messes that even the best vacuums can't handle alone. I'm talking about muddy footprints that get tracked inside on rainy days, soda that gets knocked onto the floor ...

The load is now a boiler. (See Figure 4, page 20.) This wiring diagram shows 120 V coming from L1 of a circuit breaker, through a switch, powering a boiler control and returning through L2, back to ...