Simplex 2081-9028 — Isolated Loop Circuit Protector (ILCP) for Simplex circuits carrying up to 5 A.
Any fire alarm conductor that leaves the building — a NAC to a detached structure, an SLC crossing a yard — sees lightning and power-line transients that will take out panel drivers. This epoxy-encapsulated protector installs where the circuit crosses the envelope and clamps line-to-line and line-to-earth in under a nanosecond, with series resistance low enough for a high-current NAC or audio run.
- 5 A continuous DC or audio; 38 VDC / 28 VAC RMS line-to-line, 48 VDC / 33 VAC RMS to ground
- 0.1 Ω/line, 68 µH/line, 0.017 µF shunt
- Surge 2000 A (8 × 20 µs) line-to-line and line-to-earth
- For DC NACs, 25 VRMS speaker circuits, IDNAC and TrueAlert SLCs
- 3-3/8" × 2" × 1"; 18 AWG color-coded leads; UL 497B certified
This is an isolated loop circuit protector, not an overvoltage protector — for UL 864 overvoltage duty order 2081-9044, and under 200 mA order 2081-9027. Needs a dedicated 4" square metallic box.
Documents
FAQ
Where should the 2081-9028 be installed?
As close as possible to the point where the circuit leaves or enters the building, in a dedicated metallic 4 in. square box at least 2-1/8 in. deep.
Which circuits can it protect?
DC notification appliance circuits, 25 VRMS speaker circuits, and IDNAC and TrueAlert SLCs, at up to 5 A.
Is it an overvoltage protector?
No. It is an isolated loop circuit protector; for overvoltage protector duty Simplex specifies the 2081-9044, and for loads up to 200 mA the 2081-9027.
Are there wiring distance limits?
Yes. IDNAC and TrueAlert SLC runs are limited to 1000 ft with at most two ILCPs per branch, and total wiring must stay on one property and under 3270 ft (1 km).
