Point at or tap any part to name it. Tap the person, the breaker, or the worn spot in the pole to change them.
Amber dots show the light's normal current. Red diamonds show fault current and current through the person. Current under 1 mA is not drawn.
Dot speed shows how much current flows, on one scale. Currents under 1 A are drawn at a slow minimum speed so you can see them.
On AC the current turns around 120 times a second. The dots show where it flows and how much. Real electrons drift slower than a snail.
The fault and the trip are shown 100 times slower than real life.
The ground wire and the main bonding jumper give fault current a low-resistance path back to the transformer, so the breaker trips, 250.4(A)(5) and 250.24(C).
The earth is never that path, 250.4(A)(5)(c). A rod at the pole is allowed as an extra, never in place of the ground wire, 250.54.
The ground rod ties the system to the earth. It limits voltage from lightning and surges and keeps the system near earth voltage, 250.4(A)(1). It does not trip a breaker.
One rod of 25 Ω or less to earth needs no second electrode, 250.53(A)(2) Exception. Both rods here are drawn at 25 Ω.
With only a rod, the pole reads 102 V, not 120 V. The other volts drop across the house and utility grounds. A worse rod puts the pole closer to 120 volts.
12 AWG copper on a 20 A breaker, 240.4(D)(6), with a 12 AWG ground wire, Table 250.122. 100 ft to the pole at 1.98 Ω per 1,000 ft, Chapter 9, Table 8.
Teaching model. The transformer and service drop are 0.02 Ω, the utility's grounds 5 Ω, a solid fault 0.01 Ω, and the 60 W light 240 Ω.
A typical 20 A breaker trips on its magnet in about one cycle, 17 ms, at 10 times its rating or more. That is maker data, not code.
The person is drawn as 1,000 Ω from hand to feet, with wet skin on wet grass. Shock effects are typical OSHA figures, not code. The real shock depends on where they stand.
The pole's concrete base is not counted as a path to earth. Yard lighting outlets need no GFCI, 210.8(F) Exception No. 1.
The drop is dead-ended on an insulator below the weatherhead and spliced to the service-entrance wires in drip loops, 230.54(C) and 230.54(F).