NEC 2020 (NFPA 70): Article 760 and Wiring Methods
NFPA 70 (NEC) 2020 Art. 760, Parts I through IV · NEC 2020 §90.3, §90.5, §110.12, §110.26, §250.4 · NEC 2020 §300.4, §300.11, §300.15, §300.21, §300.22, §314.16 · NEC 2020 Art. 770 (optical fiber) · Outline tasks 1.1.2, 1.3.1, 1.2.2
What NICET expects at Level I
Task 1.1.2 (install cabling and associated infrastructure) is one of the most heavily weighted tasks on the exam, and its main reference is NEC 2020 (NFPA 70), Article 760. A Level I technician does not design: you must choose the right cable for each space (plenum, riser, general use), support and protect it, keep it separated from power circuits, firestop penetrations, and know where the panel (FACU) gets its power and how that circuit is identified. Points go to whoever can navigate Article 760 in seconds, not to whoever memorized it.
Remember that Article 760 is in Chapter 7 and, per 90.3, it supplements or modifies the general rules. Key example: per 760.3, only the Article 300 sections that Article 760 itself references apply.
Structure of Article 760
| Part | Sections | What it contains |
|---|---|---|
| I. General | 760.1 to 760.35 | Scope, definitions (760.2), other articles (760.3), access (760.21), execution of work (760.24), abandoned cables (760.25), identification (760.30), circuits extending beyond one building (760.32), which Parts apply (760.35) |
| II. NPLFA | 760.41 to 760.53 | Power source and branch circuit, overcurrent protection, wiring methods, conductors, NPLF/NPLFR/NPLFP cables |
| III. PLFA | 760.121 to 760.154 | PLFA sources, marking, supply-side and load-side wiring methods, separation, circuit mixing, conductor size, support, cable applications and substitutions |
| IV. Listing | 760.176 and 760.179 | Listing and marking of NPLFA and PLFA cables (including the CI suffix) |
760.35 rule: NPLFA = Parts I and II; PLFA = Parts I and III. Most modern systems (SLCs, NACs, 24-V initiating circuits) are PLFA.
Definitions to master (760.2)
- Fire alarm circuit: the portion of the wiring and connected equipment powered and controlled by the fire alarm system; classified as PLFA or NPLFA.
- PLFA: a circuit powered by a source that complies with 760.121 (a listed PLFA or Class 3 transformer or power supply, or listed equipment marked as a PLFA source).
- NPLFA: a circuit powered by a source that complies with 760.41 and 760.43 (up to 600 V nominal).
- Abandoned fire alarm cable: cable that is not terminated at equipment and not identified for future use with a tag.
- Circuit integrity (CI) cable: cable that keeps critical circuits operating for a specified time under fire conditions.
Part I: general installation rules
- 760.3: points to other rules that apply, including 300.21 (firestopping penetrations of fire-resistance-rated construction), 300.22 (ducts, plenums, and other air-handling spaces), Article 725 for building control circuits not powered by the fire alarm system, Article 770 for optical fiber, and a few other listed Chapter 3 sections.
- 760.21: an accumulation of cables must not prevent removal of access panels, including suspended ceiling panels.
- 760.24(A): neat and workmanlike installation; exposed cables supported by the building structure using straps, staples, cable ties, hangers, or similar fittings that do not damage the cable; comply with 300.4(D) and 300.11. Nonmetallic cable ties and accessories used in plenums must be listed for low smoke and heat release.
- 760.24(B): CI cable supported at no more than 24 in. (610 mm); within 7 ft of the floor, fastened every 18 in. (450 mm); supports and fasteners of steel.
- 760.25: remove the accessible portion of abandoned cables; cable left for future use needs a tag durable enough for the environment.
- 760.30: identify fire alarm circuits at terminal and junction locations to prevent unintentional signals while testing or servicing other systems. The NEC does not require the color red.
FACU power supply (760.41(B) and 760.121(B))
- The branch circuit supplies no other loads.
- It may not be supplied through a GFCI or AFCI.
- The location of the overcurrent device is permanently identified at the FACU.
- The disconnecting means has red identification, is accessible only to qualified personnel, and is identified as 'FIRE ALARM CIRCUIT'; the red identification must not damage the breaker or obscure the manufacturer's markings.
NFPA 72 (Ch. 10) has parallel requirements for the branch-circuit disconnect, including an approved breaker locking device (NFPA 72 §10.6.5.4). If a question cites the NEC, answer with 760.41/760.121; if it cites NFPA 72, look in Chapter 10.
Key numbers
| Requirement | Value | Section |
|---|---|---|
| Maximum NPLFA source voltage | 600 V nominal | 760.41(A) |
| NPLFA overcurrent, 18 AWG / 16 AWG | 7 A / 10 A | 760.43 |
| Ampacity of 18 and 16 AWG NPLFA | Table 402.5 (6 A / 8 A) | 760.49(A) |
| NPLFA conductor insulation | not less than 600 V | 760.49(B) |
| Supply-side overcurrent for a PLFA source | not over 20 A | 760.127 |
| PLFA cable voltage rating | not less than 300 V (and 60°C) | 760.179(C) |
| Single PLFA conductor | not smaller than 18 AWG (26 AWG only with listed connectors or equipment) | 760.142 |
| Exposed PLFA cable within 7 ft of the floor | fastened every 18 in. (450 mm) max. | 760.130(B)(1) |
| PLFA passing through a floor or wall | metal raceway or RNC up to 7 ft (2.1 m) | 760.130(B)(2) |
| PLFA in hoistways | in raceway (RMC, IMC, RNC, LFNC, or EMT), or per 620.21 for elevator equipment | 760.130(B)(3) |
| PLFA separation from power/Class 1/NPLFA (open runs) | 2 in. (50 mm) | 760.136(G) |
| Separation inside enclosures (associated equipment) | 1/4 in. (6 mm) | 760.136(D) |
| CI cable support | 24 in. max., steel | 760.24(B) |
| Cable parallel to wood studs | 1¼ in. from the edge or a 1/16 in. steel plate | 300.4(D) |
| Working space, 0 to 150 V to ground | 3 ft deep, 30 in. wide, 6½ ft high | 110.26(A) |
| Box volume per 14 AWG conductor | 2.00 in³ | Table 314.16(B) |
Cable types and substitutions
| Space | PLFA | NPLFA | PLFA substitutes (Table 760.154(A)) |
|---|---|---|---|
| Plenum: other space used for environmental air (300.22(C)) | FPLP | NPLFP | CMP |
| Riser: vertical runs between floors | FPLR | NPLFR | CMP, FPLP, CMR |
| General use | FPL | NPLF | CMP, FPLP, CMR, FPLR, CMG, CM |
Core idea: you can always use a cable higher in the hierarchy, never a lower one. Table 760.154 says where each type goes; for example, in a plenum FPLR and FPL are permitted only inside metal raceway that complies with 300.22(C). When a substitute is used, Parts I and III still apply. The -CI suffix (FPLP-CI, FPLR-CI, FPL-CI) indicates 2-hour circuit integrity cable. For optical fiber (Art. 770): OFNP/OFCP in plenums, OFNR/OFCR in risers, and OFN/OFNG for general use.
Mixing circuits
- 760.48: Class 1 and NPLFA may share a raceway if all conductors are insulated for the maximum voltage present; power and fire alarm conductors only where connected to the same equipment.
- 760.136(A): PLFA may not share a cable, box, raceway, or cable tray with light, power, Class 1, or NPLFA conductors, except with a barrier (B), a raceway within the enclosure (C), or associated equipment with 1/4 in. separation (D), among other cases.
- 760.139: multiple PLFA circuits together, yes; Class 2 with PLFA, yes, if its insulation is at least that required for PLFA; audio circuits (640.9(C)) with PLFA, no.
- 760.130(A), Exception No. 3: a PLFA circuit may be reclassified as NPLFA if the 760.124 markings are eliminated and the entire circuit is installed with Part II wiring methods and materials.
- 760.143: never strap or tape PLFA cable to the outside of a raceway as a means of support.
Frequent traps:
- Confusing 7 A / 10 A (maximum protection, 760.43) with the Table 402.5 ampacity.
- Believing the NEC requires red conduit or red boxes: the mandatory red is the identification of the branch-circuit disconnect.
- Assuming a FACU may be fed from a GFCI/AFCI circuit or from a circuit shared with other loads.
- Thinking FPL can never enter a plenum: it can, inside metal raceway that complies with 300.22(C).
- Mixing up 2 in. (open runs, 760.136(G)) and 1/4 in. (inside enclosures, 760.136(D)).
- 300 V (PLFA cable) vs. 600 V (NPLFA conductors). And the voltage is not printed on PLFA cables (760.179(I)).
- Using the suspended ceiling grid or its wires as support (prohibited by 300.11(B)).
- Older guides cite '760.154(D)'; in NEC 2020 the substitutions are in 760.154(A) and Table 760.154(A).
How to find it fast in the printed code
- First decide whether the question is about PLFA (Part III, 760.121 and up) or NPLFA (Part II, 760.41 to 760.53).
- Article 760 sits in Chapter 7 of the NEC; place a permanent tab at 760.1 and another at Table 760.154 / Table 760.154(A), the most-used pages of the article.
- In the NEC index, look under "Fire alarm systems" and "Power-limited fire alarm circuits," and for terms such as "Abandoned cable," "Plenums," and "Circuit integrity cable."
- For Article 300, confirm in 760.3 that the section is referenced; if it is not, it probably does not apply to the fire alarm wiring.
- Highlight the key numbers in your book: 7 A/10 A (760.43), 18 in. and 7 ft (760.130), 2 in. and 1/4 in. (760.136), 24 in. steel (760.24(B)). Informational Notes are explanatory, not requirements (90.5(C)).
Edition note: NEC 2023 created Article 722 (cables for power-limited circuits) and moved part of the cable installation and listing requirements there, and it added a surge-protection requirement for the FACU. The NICET exam uses NEC 2020: answer with the 2020 numbering.
What to tab in your books
| Section | Why |
|---|---|
| NEC 2020 §760.2 | Definitions: PLFA, NPLFA, abandoned cable, CI cable |
| NEC 2020 §760.3 | Other articles that apply (300.21, 300.22, Art. 725, Art. 770) |
| NEC 2020 §760.21 | Access: cables must not prevent removal of ceiling panels |
| NEC 2020 §760.24 | Workmanship, support, plenum cable ties; CI supported every 24 in. with steel |
| NEC 2020 §760.25 | Abandoned cables and future-use tags |
| NEC 2020 §760.41 / §760.121 | FACU branch circuit: no other loads, no GFCI/AFCI, red, 'FIRE ALARM CIRCUIT' |
| NEC 2020 §760.43 | NPLFA protection: 7 A (18 AWG), 10 A (16 AWG) |
| NEC 2020 §760.49 | NPLFA conductors: Table 402.5, 600 V insulation |
| NEC 2020 §760.53 | NPLFA cables: NPLF, NPLFR, NPLFP |
| NEC 2020 §760.127 | Supply side of a PLFA source: 20 A max. protection |
| NEC 2020 §760.130 | PLFA load-side methods: 18 in. below 7 ft, floor/wall penetrations, hoistways, splices, reclassification |
| NEC 2020 §760.136 | Separation from power: barriers, 1/4 in. in enclosures, 2 in. in open runs |
| NEC 2020 §760.139 | PLFA with Class 2/3 and communications; audio prohibited |
| NEC 2020 §760.143 | Do not use the outside of raceways as support |
| NEC 2020 Table 760.154 and 760.154(A) | PLFA cable applications and substitution hierarchy |
| NEC 2020 §760.179 | PLFA listing and marking: 300 V, FPLP/FPLR/FPL, CI, no voltage marking |
| NEC 2020 §300.4 and §300.11 | Protection against nails (1¼ in., 1/16 in. plate) and support above suspended ceilings |
| NEC 2020 §300.21 and §300.22 | Firestopping penetrations and environmental air spaces (plenums) |
| NEC 2020 Table 110.26(A)(1) | Working space in front of the FACU (3 ft at 0–150 V) |
| NEC 2020 Table 314.16(B) | Volume allowance per conductor for box fill |
Chapter vocabulary
- Fire alarm circuit
- The portion of the wiring and connected equipment powered and controlled by the fire alarm system; PLFA or NPLFA.
- Power-limited fire alarm (PLFA) circuit
- Circuit powered by a source that complies with 760.121; installed per Parts I and III of Article 760.
- Non-power-limited fire alarm (NPLFA) circuit
- Circuit powered by a source that complies with 760.41 and 760.43, up to 600 V; Parts I and II.
- Abandoned fire alarm cable
- Cable not terminated at equipment and not identified for future use with a tag; its accessible portion must be removed.
- Circuit integrity (CI) cable
- Cable listed to keep critical circuits operating for a specified time under fire conditions; carries the CI suffix.
- Other space used for environmental air (plenum)
- Space, such as above a return-air suspended ceiling, that forms part of the air-handling system (300.22(C)).
- Riser
- Vertical cable run penetrating more than one floor or in a vertical shaft; requires riser-type cable (FPLR) or better.
- Cable substitution
- Using a cable with equal or better fire performance in place of the one required, per Table 760.154(A).
- Firestopping
- Approved sealing of penetrations in fire-resistance-rated walls, floors, or ceilings (300.21).
- Branch circuit
- Conductors between the final overcurrent device and the outlets; the FACU branch circuit must not supply other loads.
- Overcurrent protective device (OCPD)
- Breaker or fuse that protects the conductors; for the FACU circuit, its location is identified at the FACU.
- Disconnecting means
- Device that disconnects a circuit from its source; for fire alarm it has red identification and is labeled 'FIRE ALARM CIRCUIT'.
- Qualified person
- Person with the skills, knowledge, and safety training to install and operate the equipment; only such persons may access the fire alarm disconnect.
- Raceway
- Enclosed channel designed to hold conductors or cables, such as EMT, RMC, or rigid PVC conduit.
- Electrical metallic tubing (EMT)
- Thin-wall metal raceway; FPL and FPLR are permitted inside it in plenums (Table 760.154).
- Equipment grounding conductor (EGC)
- Conductor that connects the metal parts of equipment back to the source so ground faults are cleared.
- Effective ground-fault current path
- Low-impedance path that allows the overcurrent device to operate; the earth is not considered one.
- Working space
- Clear space in front of equipment examined or serviced while energized (110.26): 3 ft deep at 0–150 V.
- Box fill
- Calculation of the minimum box volume based on the conductors and devices it contains (314.16).
- Barrier
- Fixed divider that allows PLFA and power conductors in the same enclosure (760.136(B)).
- Informational note
- Explanatory NEC material that is not an enforceable requirement (90.5(C)).
- Listed
- Equipment or material included in a list published by a certification organization acceptable to the AHJ, showing it meets defined standards.
- Neat and workmanlike manner
- Quality of workmanship required by 110.12 and 760.24(A): cables orderly, supported, and undamaged.
- Cable tie
- Cable fastener; nonmetallic ties used in plenums must be listed for low smoke and heat release.
- Optical fiber cable (OFNP/OFNR/OFN)
- Cable installed per Article 770; OFNP for plenums, OFNR for risers, OFN/OFNG for general use.
50 practice questions cover this chapter, each with an explanation and the code section. Get lifetime access or try the free practice exam.
More Level I study guides
- 8-week study plan
- Fundamentals and Definitions
- Initiating Devices
- Notification Appliances
- Circuits, Systems, and Control Functions
- NEC 2020 (NFPA 70): Article 760 and Wiring Methods
- Basic Electricity and Calculations
- Inspection, Testing and Maintenance
- Troubleshooting, Repair and Device Replacement
- Job Site Safety: OSHA 1910/1926 and First Aid
- Technical Documents, Drawings, and Submittals
- Community-Reported Topics
- Level I tabbing guide for your printed code books
- Strategy with printed code books
- Key numbers (NFPA 72 · NEC · OSHA)
- Formulas and conversions
- Fire alarm glossary for the NICET exams