The KOBOLD NEK is a compact conductive level switch that monitors the level of sufficiently conductive liquids in tanks. It applies a low AC voltage to a pair of 316-Ti stainless steel electrodes; when a conductive liquid bridges them, a small current flows and the switch changes state. With no moving parts and a solid-state design, the NEK is well suited to dirty, low-viscosity, or aggressive conductive liquids. Bodies are offered in PPS or polypropylene, with NPN open collector, PNP open collector, or SPDT relay outputs.
How the NEK conductive level switch works
The NEK operates on the conductive measuring principle. As soon as a conductive medium contacts both electrodes, a negligible alternating current flows and the output switches state. Switching occurs after a 0.5 second delay, and a built-in LED shows whether the switch is dry or wet.
Body materials, pressure, and temperature ratings
The NEK body is available in PPS or polypropylene, and the sensing electrodes are 316-Ti stainless steel. The PPS body is rated to 290 PSIG (20 bar) with a media temperature range of -10 to 185°F (-23 to 85°C). The polypropylene body is rated to 87 PSIG (6 bar) with a range of -10 to 140°F (-23 to 60°C). The minimum media conductivity is 100 µS/cm, and enclosure protection is NEMA 6 / IP68.
Electrical outputs and connection
Three output types are available: NPN open collector, PNP open collector, and SPDT relay. The open collector output is normally open when dry, rated 32 VDC and 100 mA maximum, and short-circuit protected. The relay output is rated 1 amp at 30 VDC maximum. The NEK runs on an 18-29 VDC supply and connects by a 6 ft (1.8 m) PVC cable.
Installation and dimensions
The NEK mounts in the top or side of a tank, horizontally or vertically, through a 3/4 inch NPT process connection, and is offered in 1-1/2 inch (38 mm) or 3 inch (76 mm) immersion lengths. During installation, keep mechanical pressure off the unit, avoid tensile or torsional stress, and check the fitting for leaks. If the NEK is mounted in a metallic, conductive container, connect the container to the NEK supply ground to prevent potential differences.
Suitable media and applications
The NEK is designed for economically monitoring sufficiently conductive liquids in tanks. Because it has no moving parts, it suits critical media with a high solids content or with negligible density or high viscosity. The 316-Ti stainless steel electrodes let it work with many compatible chemicals and aggressive conductive media in use today. The switch is maintenance-free; if the electrodes develop a non-conductive coating such as oil or grease, they can be wiped clean with a cloth.
The NEK is made in the USA.
Common Questions about NEK - Compact Conductive Level Switch
The NEK monitors sufficiently conductive liquids in tanks and needs a minimum media conductivity of 100 µS/cm. Its solid-state design copes with dirty liquids that carry a high solids load, and the 316-Ti stainless steel electrodes are compatible with many chemicals and aggressive conductive media.
The NEK is offered with a PPS or a polypropylene housing and 316-Ti stainless steel sensing electrodes. Housing choice fixes the pressure and temperature limits: PPS carries the higher ratings, while polypropylene suits less demanding service.
With a PPS body the NEK withstands 290 PSIG (20 bar) and media from -10 to 185°F (-23 to 85°C). With a polypropylene body it is rated for 87 PSIG (6 bar) and -10 to 140°F (-23 to 60°C).
Choose from three outputs: open collector NPN, open collector PNP, or an SPDT relay. Open collector models allow up to 32 VDC and 100 mA and are short-circuit protected, and the relay is rated for 1 amp at 30 VDC. Every model is powered from 18-29 VDC.
The NEK connects through a 3/4 inch NPT fitting and comes in two immersion lengths, 1-1/2 inch (38 mm) and 3 inch (76 mm). It is supplied with a 6 ft (1.8 m) PVC cable and carries a NEMA 6 / IP68 protection rating.
Install the NEK from the top of a tank or from the side, either horizontally or vertically. Avoid pressure and tensile or torsional stress during installation, then check the connection for leakage. Inside a metallic, conductive container, the container must be bonded to the NEK supply ground.
The LED reports the switch state. It stays off when there is no power. With power applied and the switch dry, or deactivated, the LED gives short on pulses. With power applied and the switch wet, or activated, the LED stays on.
Yes. This conductive level switch is maintenance-free. If the electrodes pick up a non-conductive film such as oil or grease, wipe them clean with a suitable cloth. Do not use a cleaner that would damage the plastic housing.
Order codes follow the example NEK-1136 N20 C. In the four-digit number, the first digit is the output (1 = NPN, 2 = PNP, 3 = SPDT relay), the second digit is the body (1 = PPS, 2 = polypropylene), and the last two digits are the immersion length (36 = 1-1/2 inch, 73 = 3 inch). N20 is the 3/4 inch NPT fitting and C is the 6 ft PVC cable.
Product Specifications
Compatible Media
For Conductive Liquids Only
Body Material
Polypropylene or PPS
Sensing Electrode Material
316-Ti SS
Max. Pressure
Polypropylene = 87 PSIG, PPS = 290 PSIG
Max. Temperature
Polypropylene = 140 °F (60 °C), PPS = 185 °F (85 °C)
Switching Output
PNP or NPN Open Collector or SPDT Relay
Product Features
Excellent for Dirty, Low-Viscosity or Aggressive Conductive Liquids
Transistor Switch or Relay Output
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