Final answer:
True, GFCIs are required for 120v power tools on all NCF project sites to provide safety against electric shocks by interrupting circuits with leakage currents above 5 mA.
Step-by-step explanation:
True, a Ground Fault Circuit Interrupter (GFCI) is required for the use on 120v power tools on all NCF project sites. A GFCI is a safety device designed to prevent electrical shock by breaking the circuit whenever there is a difference in currents between the live/hot and neutral wires. This typically happens when leakages occur, indicating current is following an unintended path possibly presenting a hazard.
The GFCI is effective in detecting and interrupting leakage currents greater than 5 mA, which is the accepted maximum harmless shock threshold. Therefore, it's in place to prevent the risk of electric shock hazards on construction sites, effectively ensuring a safer work environment. Its use is especially critical around areas where electrical equipment might come into contact with water or damp conditions.