NWSA Electrical Safety and Grounding 2 — Questions and Answers
Question 1: What is the maximum acceptable ground resistance for a properly installed communication tower grounding system?
- 1 ohm
- 5 ohms
- 10 ohms (Correct answer)
- 25 ohms
Correct answer: 10 ohms
Industry and TIA standards generally require tower grounding resistance to be 10 ohms or less for effective lightning and fault current dissipation.
Question 2: Arc flash rated PPE must be worn when a worker is:
- Climbing any communication tower structure
- Within the arc flash boundary of energized electrical equipment (Correct answer)
- Using any cordless battery-powered tool
- Installing coaxial cable on a grounded antenna mount
Correct answer: Within the arc flash boundary of energized electrical equipment
Workers must wear arc flash rated PPE whenever they are within the arc flash boundary established by the site's hazard analysis for energized equipment.
Question 3: Temporary protective grounds must be installed on de-energized electrical conductors:
- Before any work begins to protect against accidental re-energization (Correct answer)
- Only at the end of each workday
- Only during active lightning storms
- Only by state-licensed electricians
Correct answer: Before any work begins to protect against accidental re-energization
Temporary grounds must be applied before work begins on de-energized conductors to protect against inadvertent re-energization from any source.
Question 4: What is the minimum copper conductor size typically required for a communication tower grounding conductor per industry standards?
- 14 AWG solid copper
- 10 AWG stranded copper
- 2 AWG solid copper
- 6 AWG copper (Correct answer)
Correct answer: 6 AWG copper
A minimum of 6 AWG copper is typically specified for tower grounding conductors to handle the high-current demands of lightning events.
Question 5: An assured equipment grounding conductor program (AEGCP) on a construction site is an acceptable alternative to:
- Lockout/tagout procedures
- GFCI protection for cord-connected equipment (Correct answer)
- Arc flash PPE requirements
- Personal fall arrest systems
Correct answer: GFCI protection for cord-connected equipment
Under OSHA 1926.404(b)(1)(ii), a written and enforced AEGCP is an approved alternative to GFCI protection for cord-connected tools and equipment on construction sites.
Question 6: Capacitors in recently de-energized electrical equipment are dangerous because they:
- Prevent the equipment from restarting after service
- Cause interference with nearby communications equipment
- Can still deliver a lethal shock even after the power source is disconnected (Correct answer)
- Only pose a risk to the equipment itself, not to personnel
Correct answer: Can still deliver a lethal shock even after the power source is disconnected
Capacitors store electrical charge and can release it as a dangerous or lethal shock even when the power supply has been disconnected.
NWSA Electrical Safety and Grounding 2
What is the maximum acceptable ground resistance for a properly installed communication tower grounding system?