NABCEP Building and Fire Codes 5 — Questions and Answers
Question 1: The 2021 IFC allows PV systems to be exempt from roof access pathway requirements if the building is protected throughout by an approved automatic sprinkler system AND the array is less than what size threshold?
- 50% of the roof area (Correct answer)
- 33% of the roof area
- 2,000 square feet
- The sprinkler exemption does not exist; pathways are always required
Correct answer: 50% of the roof area
The 2021 IFC allows a pathway exemption when the building is fully sprinklered and the array covers less than 50% of the roof area.
Question 2: Under the IBC and ASCE 7, ground-mounted solar arrays in seismic design categories D, E, or F must use which load combination approach?
- ASD (Allowable Stress Design) only
- LRFD or ASD load combinations incorporating seismic effects per ASCE 7 Chapter 12 (Correct answer)
- Simplified seismic loads per IBC Section 1613.2 only
- No seismic analysis is required for ground-mounted arrays under 15 feet tall
Correct answer: LRFD or ASD load combinations incorporating seismic effects per ASCE 7 Chapter 12
In high seismic categories, arrays must be designed using full LRFD or ASD load combinations that include seismic effects per ASCE 7 Chapter 12.
Question 3: What label must appear at the utility revenue meter of a PV-interconnected system per the NEC to alert utility workers?
- 'CAUTION: DUAL FEED — DO NOT OPEN UNDER LOAD'
- 'WARNING: PHOTOVOLTAIC SYSTEM CONNECTED' (Correct answer)
- 'DANGER: INTERACTIVE SYSTEM — CONTACT UTILITY BEFORE SERVICING'
- 'NOTICE: RENEWABLE ENERGY SOURCE PRESENT'
Correct answer: 'WARNING: PHOTOVOLTAIC SYSTEM CONNECTED'
NEC 690.64 requires a label reading 'WARNING: PHOTOVOLTAIC SYSTEM CONNECTED' at the utility meter for any grid-interactive PV system.
Question 4: Under NFPA 855, what minimum separation distance is required between individual ESS units in a Group B occupancy to qualify as separate units rather than an aggregate system?
- 1 foot
- 3 feet (Correct answer)
- 10 feet
- 6 feet
Correct answer: 3 feet
NFPA 855 requires a minimum 3-foot separation between individual ESS units to prevent thermal runaway propagation and qualify each as an independent unit.
Question 5: Which code section requires that the main service panel have a label indicating the presence of a backfed PV circuit breaker and that the breaker be positioned at the opposite end from the main breaker?
- NEC 705.12(B)(2) — load-side connection and maximum breaker position (Correct answer)
- NEC 690.64 — utility meter labeling
- NEC 230.82 — service entrance equipment
- NEC 408.36 — panelboard overcurrent protection
Correct answer: NEC 705.12(B)(2) — load-side connection and maximum breaker position
NEC 705.12(B)(2) requires the PV supply breaker to be at the opposite end of the bus from the main breaker and limits total bus loading to 120% of the bus rating.
Question 6: When a PV system is installed on a building in a high-fire-hazard severity zone (HFHSZ) in California, which additional requirement applies beyond standard IFC provisions?
- All wiring must be in rigid metal conduit
- Modules must carry a Class A fire rating per California Fire Code Chapter 49 (Correct answer)
- A defensible space of 100 feet must surround ground-mounted arrays
- Array inverters must be located in a fire-rated enclosure
Correct answer: Modules must carry a Class A fire rating per California Fire Code Chapter 49
California Fire Code Chapter 49 requires that PV modules installed in HFHSZs carry a Class A fire rating to reduce ignition potential from airborne embers.
Question 7: A PV system's utility-interactive inverter must comply with which standard to ensure automatic anti-islanding and grid disconnection during a utility outage?
- UL 1741 and IEEE 1547 (Correct answer)
- ANSI C12.20 and NEMA MG-1
- UL 508A and IEEE 519
- IEC 61730 and UL 2703
Correct answer: UL 1741 and IEEE 1547
Grid-interactive inverters must be listed to UL 1741 and comply with IEEE 1547, which together mandate anti-islanding protection and automatic disconnection upon loss of utility voltage.
NABCEP Building and Fire Codes 5
The 2021 IFC allows PV systems to be exempt from roof access pathway requirements if the building is protected throughout by an approved automatic sprinkler system AND the array is less than what size threshold?