If you have ever stared at a submittal and wondered why the spec calls for a PC2WLED when you have a box of P2WLED on the truck, you are not alone. System Sensor L-Series part numbers pack mounting, color, wiring, environment and lens marking into six or seven characters. Once you know the structure, you can read any of them at a glance.
This guide breaks down the pattern using the L-Series notification appliances we stock. It covers what the part number tells you, and just as importantly, what it does not.
The structure
Every L-Series part number follows the same order:
[device type] + [mount] + [size] + [color] + [environment] + [series] + [light source] + [suffixes]
Not every position is used on every model. Letters that are absent carry meaning too, which is the part that trips people up. No C means wall mount. No K means indoor.
Device type: the first letters
| Prefix | Device |
|---|---|
| H | Horn only, no strobe |
| S | Strobe only, no audible |
| P | Horn strobe, combination audible and visual |
| SP | Speaker only |
| SPS | Speaker strobe |
| CH | Chime only |
| CHS | Chime strobe |
| MH | Mini horn |
This is the single most useful distinction to get right. An HWL is a horn. An SGWL is a strobe. A P2WLED does both. Ordering a horn when the drawing called for a horn strobe is the most common reason a notification order comes back.
The middle letters
| Letter | Meaning | If absent |
|---|---|---|
| C | Ceiling mount | Wall mount |
| G | Compact housing | Standard housing |
| 2 / 4 | 2-wire or 4-wire | Not applicable to that device |
| W / R | White or Red | — |
| K | Outdoor, weatherproof | Indoor only |
| L | L-Series | — |
The 2-wire versus 4-wire choice is a circuit decision, not a preference. A 2-wire appliance takes audible and visual power from the same pair. A 4-wire appliance separates them. Mixing them on one circuit is a design change, not a substitution.
Light source: LED or not
A part number containing LED uses an LED light source. One without it does not. Compare two otherwise identical ceiling-mount white horn strobes in our catalog:
- PC2WL — horn strobe, 2-wire, ceiling, white
- PC2WLED — the same configuration with an LED strobe
These are not interchangeable on a submittal. If the spec names one, order that one.
Suffixes after the dash
| Suffix | Meaning |
|---|---|
| -LF | Low frequency sounder, for sleeping areas |
| -P | Plain lens, no lettering |
| -SP | Marked FUEGO, Spanish |
| -ALERT | Marked ALERT instead of FIRE |
| -CLR | Clear lens |
| -TILE | Ceiling tile mount |
| -BP10 | Bulk pack, sold as a multi-unit case |
Two of these deserve attention when you are buying.
-LF means low frequency. These are audible appliances intended for sleeping areas. Note that an HWL-LF is a sounder with no strobe, while a P2WL-LF is a sounder combined with a strobe. The -LF suffix changes the audible characteristic; it does not add a strobe.
-BP10 is a bulk pack. The price you see is for the case, not a single device. On a large notification rough-in this is usually what you want, but it is worth confirming before you order a single replacement.
Worked examples
| Part number | Reads as |
|---|---|
| P2WLED | Horn strobe, 2-wire, wall, white, indoor, LED |
| PC2RLED | Horn strobe, ceiling, 2-wire, red, indoor, LED |
| P2GWKLED | Horn strobe, 2-wire, compact, wall, white, outdoor, LED |
| SCWLED-P | Strobe only, ceiling, white, indoor, LED, plain lens |
| SPSCWLED | Speaker strobe, ceiling, white, indoor, LED |
| HGRL-LF | Horn only, compact, wall, red, low frequency sounder |
What the part number does not tell you
This is the important part. The part number identifies the configuration. It does not give you the electrical or performance data you need to finish a design. For any given model, the following must come from the manufacturer's current datasheet:
- Candela settings available on the appliance and how they are selected
- Current draw at each candela setting and operating voltage
- Sound output ratings and tone options
- UL listing numbers and the listed applications
- Mounting requirements and compatible back boxes
Never size a notification appliance circuit from a part number alone. Candela selection and spacing are governed by NFPA 72 and the authority having jurisdiction, and the current draw at the selected candela is what determines how many appliances a circuit will carry. Pull the datasheet for the exact model, and confirm the selected setting matches the approved drawings.
Finding the right part
We stock the L-Series line across horn strobes, strobes, horns, speakers and speaker strobes, in wall and ceiling, red and white, indoor and outdoor, standard and compact. If you have a part number from a submittal and want to confirm availability, or you need help matching an obsolete device to a current equivalent, our team works with these every day.
Browse horn strobes and notification appliances or contact us with your part list.