What each wire does

What to try

1. 1On Healthy drill, set Hand to On the drill. The hot and the neutral carry the same current, and the ground wire carries none.
2. 2Pick Fault, three-wire. The hot touches the metal case, and the ground wire carries a large current back to the panel so the breaker trips.
3. 3Pick Fault, two-wire and set Hand to On the drill. There is no ground wire, so the current goes through the person and the breaker stays on.

NEC 2026 sections it covers

250.4(A)(5)

The ground wire gives fault current a path back so the breaker trips. The earth is not that path.

250.114

A hand-held power tool at a home needs a ground wire unless it is double-insulated.

406.12(A)

Receptacles on 15 and 20 A circuits have a ground hole.

406.12(D)(2)

On an old two-wire circuit, you may put in another two-slot receptacle or add GFCI protection.

406.12(D)(3)

In a garage, the replacement also needs GFCI protection.

406.12(D)(1)

Running a ground wire is another fix for an old two-wire circuit.

250.130(C)

It lists where that new ground wire may connect.

210.8(A)

New garage receptacles at a home need GFCI protection.

240.4(D)

12 AWG copper gets a 20 A breaker at most.

Table 250.122

A 20 A circuit gets a 12 AWG copper ground wire.

Section numbers only. Read the full text in your code book. Temperatures and times in the visual are teaching models.

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