Intrinsically Safe Alarm connects to any simple apparatus like a float switch.  When triggered, gives a loud alarm and flashing LED.

  • Uninterruptible battery power is always on.
  • Replaceable lithium battery lasts for years.
  • Low battery alert.
  • Smart software allows continuous alarm for one month!
  • Very loud buzzer is 98 dB per 2 feet (like a smoke alarm)
  • Durable. Built for rough, wet and corrosive environments. IP65.
  • Additional relay output.
  • Class I, Div. 1. Groups C, D
  • 60079-0 and 60079-11. Zone 0.


Connects to a normally closed (or open) contact and converts it to a loud buzzer and a flashing LED. The 98 dB buzzer has a unique warbling sound that carries and cuts through factory noise. The enclosure is waterproof and suitable for outdoor locations. Bright LED can be seen for all angles. Runs from battery power so installation involves nothing more than mounting it.  No approvals or electricians required. 


When a switch contact (like a float switch) changes to “open” state, the buzzer sounds and the beacon LED flashes. When this happens, the buzzer can be silenced by pressing the front button. This will silence the buzzer for 30 minutes. (in the default operating mode) Meanwhile, the LED continues to flash until the liquid level is corrected. When the alarm condition is corrected, everything resets automatically. If the alarm is not actively alarming, then the front button tests the alarm.

There are different behaviors that can be selected using the DIP switches inside the box. Here are the modes to choose from:

  • 30-minute snooze alarm.  (buzzer sounds again 30 mins. after being silenced) This is the default mode.
  • Also in the default mode, the buzzer, LED, and relay are automatically reset when the liquid is corrected. However there is an option to require an operator to press the button to reset.
  • relay N.O./N.C.
  • relay output delayed 15 minutes. 


Durable PVC enclosure is certified to IP65 ingress protection. (NEMA 4X)  Suitable for outdoor use and aggressive corrosive conditions. Temperature range from + 60ºC to -40º C.

The battery is a high-capacity lithium battery with a remarkable lifespan of 20 years shelf life. In addition, intelligent software also conserves battery: if an alarm event persists for longer than 60 minutes, the IS-AB goes into a lowered output mode with only 20% duty cycle. This allows a single battery to continuously alarm for almost a month!  In addition, the alarm box has a low battery signal. When it is time to replace the battery, its as simple as plugging in a replacement, and this may be done in the hazardous location.


A popular option for the intrinsically safe alarm is to order with a liquid level probe. This allows the electronics enclosure to be located at ground level where it is convenient for an operator to reach, while the float-switch probe is at the top of a tall tank.   These level probes are available in various materials.  316 stainless steel is a popular option with the I.S. Alarm box. The available options are in the ordering section below which allow you to choose the best probe material and float switch type. More information on float switch selection and specifications.

The optional relay output sends a contact close, or contact open, to another device located in the non-hazardous location through an approved Intrinsically Safe barrier. The relay output can be ordered in the options section below.

The IS-AB is quite versatile and is not limited to float switches. Instead, the I.S. alarm box can be connected to any “Simple Apparatus” such as temperature switches, flow switches, pressure switches and more.

Intrinsically Safe Temperature Switch

Intrinsically Safe Alarm Box with Liquid Level
Intrinsically Safe Alarm Sounder
LABEL (click to enlarge)
Hazardous Location Alarm




Intrinsically safe alarm box for Class I, Div. I Hazardous Locations.


Stainless Steel FLOAT SWITCH Level ProbeFloat Switch Level Probe
Stainless Steel float

316 Stainless steel float switch mounted in a rigid 316 stainless steel pipe.  1 inch NPT SS tank mount is standard. Includes 10 ft. cable.

Float Switch Level Probe
BUNA float

BUNA rubber float switch mounted in a BUNA float switchrigid 316 stainless steel pipe.  1 inch NPT PVC tank mount is standard. Includes 10 ft. cable.



Relay output on Intrinsically Safe Alarm boxRelay Output

A relay output for signals sent to an approved I.S. barrier. 80mA max.  10ft cable is standard.
[IS-RLY] $54

Extra cable

Extra cable length over the standard length of 10 feet that’s included. Heavy 0.032″ jacket for superior durability. Four stranded conductors x 24 gage.
[C4] $1.28/ft

Stainless Rim MountRim mounting bracket for liquid level switch

Bracket secures a tank alarm to the rim of an open tank.   more info

Battery for Intrinsically Safe AlarmReplacement Battery

This is the only battery that may be used with GIZMO I.S. alarms
[BT-IS] $45