This issue's questions:

Q. A person makes contact with the hot wire and the return wire at the same time. Will this trip the GFCI?

A. No. A ground-fault circuit-interrupter protects against electric shock from an energized conductor or from energized metal parts that are not effectively grounded. It operates on the principle of monitoring the imbalanced current between the ungrounded (hot) and grounded (neutral) conductors. In a typical 2-wire circuit, the current in amperes returning to the power supply will be the same as the current leaving the power supply (except for small leakage). If the difference between the current leaving and returning through the current transformer of the GFCI protection device is 5 milliamperes (+1 or -1 milliampere), the solid-state circuitry activates the shunt trip feature to open the switching contacts of the GFCI, there by de-energizing the circuit.

Severe electric shock or death can occur if a person touches the energized line (hot) and neutral conductor at the same time, even if the circuit is GFCI protected. This is because the current transformer within the GFCI protection device does not sense an imbalance between the departing and returning current and the switching contacts remain closed.

Q. Can a single equipment grounding conductor be used for a nonmetallic raceway that contains one 20 ampere, multi-wire circuit and one 30 ampere, 2-wire circuit?

A. Yes. This issue is covered in section 250-122(c) of the NEC book, which states that when multiple circuits are installed in the same raceway, a single equipment grounding conductor can be used for all of the circuits, sized to the largest overcurrent device protecting the conductors in the raceway. According to Table 250-122(c), the equipment-grounding conductor for a 30-ampere over current protection device is No. 10.

Q. Is it a code violation to wrap a stranded No. 12 wire around the post or a wiring device screw?

A. No. This is not directly covered by the NEC, but 110-3(b) requires all equipment to be installed in accordance with manufacturer instructions. According to wiring device manufacturers, the screws on wiring devices are listed for the termination of either solid or stranded No. 14 or No. 12 wires.