Fire Alarm Cable Substitution Hierarchy
Which cables the NEC permits in place of a required fire alarm cable, per Table 760.154. The rule is one-directional — a higher-rated cable may always replace a lower-rated one (plenum over riser over general), never the reverse. Confirm the NEC edition your jurisdiction enforces; the substitution content has been stable across recent editions.
Permitted substitutions
| Required cable | May be replaced by |
|---|---|
| FPLP | CMP |
| FPLR | CMP, FPLP, CMR |
| FPL | CMP, FPLP, CMR, FPLR, CMG, CM |
Rank order (highest to lowest)
| Rank | Cable group |
|---|---|
| 1 | Plenum (FPLP / CMP) |
| 2 | Riser (FPLR / CMR) |
| 3 | General (FPL / CMG / CM) |
How to use it
Find the cable the design requires in the left column and read across — any cable listed may be pulled in its place. The pattern is always the same: plenum outranks riser, which outranks general, and the equivalent communications cables (CMP, CMR, CMG, CM) sit alongside their fire alarm counterparts. Because FPLP and CMP sit at the top, they can go anywhere; FPL at the bottom can be replaced by the most cables but can itself replace nothing.
This hierarchy is why contractors often stock a higher-rated cable than a given run strictly needs — one plenum-rated reel covers riser and general runs too. The cable type designations themselves are on the cable types chart.
Common questions
Can I use plenum cable in place of riser or general fire alarm cable?
Yes. A higher-rated cable can always replace a lower-rated one, so plenum-rated FPLP may be used anywhere FPLR or FPL is required, and riser-rated FPLR may replace general-purpose FPL. It never works the other way — you cannot drop FPL into a plenum or riser. This is the plenum-over-riser-over-general hierarchy of NEC Table 760.154.
Can communications cable be used for fire alarm?
Per NEC Table 760.154, the equivalent communications cables may substitute: CMP for FPLP, CMP/CMR for FPLR, and CMP/CMR/CMG/CM for FPL — always following the same plenum-over-riser-over-general rule. A CMP (plenum communications) cable, being the highest-rated, may stand in for any of the power-limited fire alarm cables.
Does the substitution go both ways?
No. Substitution is strictly one direction: higher-rated for lower-rated. FPL (general) may be replaced by five higher cables, but FPLP (plenum) may only be replaced by CMP — because almost nothing outranks a plenum cable. Using a lower-rated cable where a higher one is required is a code violation, not a substitution.
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