Grounding, Bonding & Electrical Protection Flashcards
7 cards from real CPCT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Grounding, Bonding & Electrical Protection flashcards as text
What is the minimum cross-sectional area specified by TIA-607 for the TMGB?
Answer: 6 mm × 100 mm
TIA-607 specifies the TMGB must be at minimum 6 mm thick by 100 mm wide (with length as required) to provide adequate surface area for bonding connections.
During a grounding system inspection, a technician finds a high-resistance connection between the TGB and the TMGB. What is the most likely cause?
Answer: Oxidation or a loose mechanical connection on the conductor terminations
High resistance in grounding connections is most commonly caused by oxidized surfaces or loose lugs at termination points, not conductor sizing or installation order.
A lightning protection system on a building must be bonded to the telecommunications grounding system because:
Answer: NEC and TIA standards require all metallic systems to share the same grounding reference to prevent potential differences during a lightning strike
Bonding all grounding systems together prevents dangerous potential differences between metallic systems during a lightning event, which could cause arcing or equipment damage.
Which tool is used to measure the resistance of a grounding electrode to earth?
Answer: Earth ground resistance tester (fall-of-potential method)
Earth ground resistance testers using the fall-of-potential method inject current between auxiliary electrodes to accurately measure the resistance of a grounding electrode to earth.
What is the correct installation practice when the TBB must pass through fire-rated walls or floors?
Answer: The penetration must be sealed with an approved firestop system rated for the wall or floor assembly
All penetrations through fire-rated assemblies, including grounding conductors, must be sealed with UL-listed firestop materials rated to match the assembly's fire rating.
When installing telecommunications equipment racks, the grounding lug on each rack should be connected to:
Answer: The TGB in the telecommunications room using an insulated copper conductor
Equipment racks must be bonded to the TGB using an insulated copper conductor to maintain a single common ground reference for all telecommunications equipment.
What is the purpose of applying anti-oxidant compound to aluminum conductor terminations in a grounding system?
Answer: To prevent oxidation that would increase contact resistance at the termination point
Aluminum rapidly oxidizes when exposed to air, and aluminum oxide has high resistance; anti-oxidant compound prevents oxide formation and maintains a low-resistance termination.