The simple answer is no, they don’t – but they can be installed in hazardous locations. You just need to use an appropriately rated and installed safety barrier.
How does it work?
KA float switches are simple contact closure devices with no active electronic components. A simple device uses very little power, far less than what is required to ignite an explosion. Therefore, they can be used in hazardous locations provided they are operated in conjunction with appropriately rated and installed intrinsic safety barriers.
With intrinsic safety, special circuits and barriers are built into the external equipment (modules or relays) so that any wiring in the hazardous area does not carry sufficient voltage or current to cause an explosion. In other words, a safety barrier controls the power source, limiting voltage and current to a safe level.
How do I wire float switches for a hazardous location?
Below are two typical intrinsically safe installation configurations for Dual Level and Single Level installations.
The drawing shows an intrinsically safe relay with multiple inputs. If you don’t have one of these, you can use a safety barrier. You will need one input per switch point – which can mean multiple safety barrier modules.
This can get very expensive if you have multiple switch points. It will likely be worth looking at another measurement solution at this point – such as the PT-500 submersible pressure transducer, or the LPU-2428 ultrasonic sensor.
Please contact us with any questions or for technical help concerning the hazardous location installation of any KA float switch model.