CITB CITB Electrical and Mechanical Services 1 — Questions and Answers
Question 1: What minimum distance must be maintained when working near overhead power lines on a US construction site?
- 3 feet
- 10 feet (Correct answer)
- 20 feet
- 50 feet
Correct answer: 10 feet
OSHA requires a minimum clearance of 10 feet from overhead power lines up to 50 kV.
Question 2: Which document governs electrical installations in US construction buildings?
- IBC
- NFPA 70 (NEC) (Correct answer)
- ANSI A10
- OSHA 1926
Correct answer: NFPA 70 (NEC)
NFPA 70, the National Electrical Code (NEC), sets the standard for safe electrical installations in US buildings.
Question 3: What color is the grounding (earth) wire in a standard US three-wire electrical circuit?
- White
- Black
- Green or bare copper (Correct answer)
- Red
Correct answer: Green or bare copper
In US wiring, the grounding conductor is identified by green insulation or bare copper.
Question 4: What is a Ground Fault Circuit Interrupter (GFCI) used for on construction sites?
- Boosting voltage
- Protecting against electrocution from ground faults (Correct answer)
- Measuring current draw
- Connecting three-phase power
Correct answer: Protecting against electrocution from ground faults
GFCIs detect small ground fault currents and quickly cut power to prevent electrocution.
Question 5: Which pipe material is commonly used for domestic cold-water supply in US residential construction today?
- Lead
- Galvanized steel
- PEX (Correct answer)
- Cast iron
Correct answer: PEX
PEX (cross-linked polyethylene) is the dominant choice for domestic cold-water supply due to flexibility and corrosion resistance.
Question 6: What does HVAC stand for in the construction and mechanical services trade?
- High Voltage Alternating Current
- Heating, Ventilation, and Air Conditioning (Correct answer)
- Hydraulic Valve and Coolant
- Hazardous Vapor and Chemical
Correct answer: Heating, Ventilation, and Air Conditioning
HVAC stands for Heating, Ventilation, and Air Conditioning, covering climate control systems in buildings.
CITB CITB Electrical and Mechanical Services 1
What minimum distance must be maintained when working near overhead power lines on a US construction site?