Wiring Methods & Installation
Fire alarm cable types (FPL, FPLR, FPLP), conductor sizing, plenum-rated wiring, separation requirements, and shield grounding.
- Identify the three fire alarm cable types and where each is permitted
- Explain conductor sizing and voltage drop considerations for NACs
- Describe plenum space wiring requirements for fire alarm systems
- State separation requirements between fire alarm and power wiring
- Explain shield grounding practices for SLC wiring
Lesson 1
Fire Alarm Cable Types - FPL, FPLR & FPLP
Cable Type Classifications
Fire alarm wiring must use cables listed for fire alarm use. The NEC (Article 760) defines three types:
FPL (Fire Power-Limited)
Use: General purpose fire alarm
Location: Non-plenum, non-riser
Rating: Basic fire resistance
FPLR (Riser)
Use: Vertical runs between floors
Location: Risers and shafts
Rating: Flame spread resistance for vertical runs
FPLP (Plenum)
Use: Plenum spaces
Location: Air handling spaces above ceilings
Rating: Low smoke, low flame spread
Substitution Rules
FPLP can substitute for FPLR and FPL
FPLR can substitute for FPL
FPL cannot substitute for FPLR or FPLP
Exam Tip - Cable Substitution
Remember the hierarchy: FPLP > FPLR > FPL. Higher-rated cables can always substitute for lower-rated ones, but never the reverse. Plenum cable can go anywhere; general-purpose FPL cannot go in plenums or risers.
Power-Limited vs. Non-Power-Limited
Fire alarm circuits are classified as either power-limited or non-power-limited:
- Power-limited (most SLC and IDC circuits) - voltage and current are limited by the panel design
- Non-power-limited (most NAC circuits) - higher voltage and current capacity for powering notification appliances
This distinction affects wiring methods, separation requirements, and cable types.
Three fire alarm cable types exist: FPL (general), FPLR (riser), and FPLP (plenum). Higher-rated cables can substitute for lower-rated ones but not the reverse. FPLP is the most versatile - it can be used anywhere.