---
title: "Y28 Non-Contact Liquid Level Sensor: Selection, Wiring and Installation"
description: "## PPK-Y28 Non-Contact Liquid Level Sensor: Selection, Wiring and Installation The PPK-Y28 is an external capacitive sensor for detecting a liquid level at one fixed point through a compatible non-metallic pipe or flat container wall. It is available here with…"
url: "https://plugplaykit.com/docs/y28-non-contact-liquid-level-sensor-guide/"
updated: "2026-10-16"
category: Technical Support
---

# Y28 Non-Contact Liquid Level Sensor: Selection, Wiring and Installation

## PPK-Y28 Non-Contact Liquid Level Sensor: Selection, Wiring and Installation

The PPK-Y28 is an external capacitive sensor for detecting a liquid level at one fixed point through a compatible non-metallic pipe or flat container wall. It is available here with a 5 V, 12 V, or 24 V DC supply and a relay output.

## Choose the right output

| Option | When liquid is detected | Available supply |
| --- | --- | --- |
| Normally Open (NO) | The relay NO contact closes. | DC 5 V, 12 V, or 24 V |
| Normally Closed (NC) | The relay NC contact opens. | DC 5 V, 12 V, or 24 V |

Select the supply voltage that matches the DC power available in your system. The manual lists a 2 A relay output for the NO/NC versions. Confirm the connected load and all local electrical requirements before wiring a load.

## Check pipe diameter and wall thickness first

For non-metallic pipes, the outside diameter and wall thickness must be considered together. Pipes must have an outside diameter of at least 11 mm.

| Pipe outside diameter | Specified sensing wall or tube wall thickness |
| --- | --- |
| 100 mm or larger | 20 ± 3 mm |
| 80 to under 100 mm | 15 ± 2 mm |
| 60 to under 80 mm | 12 ± 1.5 mm |
| 40 to under 60 mm | 7 ± 1.0 mm |
| 30 to under 40 mm | 5 ± 1.0 mm |
| 20 to under 30 mm | 3 ± 1.0 mm |
| 10 to under 20 mm | 1.5 ± 0.5 mm |

Use a flat, uniform, insulating non-metallic installation area. Keep metal parts away from the sensing area.

## Install the sensor

1. Place the sensing sheet on the outside of the tank or pipe at the desired alarm point.
2. Attach it tightly with a suitable durable adhesive or secure it with a nylon tie for pipe installation.
3. Keep the gap between the sensing surface and the container wall below 0.5 mm; no gap is preferred.
4. Power the sensor, then adjust sensitivity only if detection is too weak or too strong for the installed container and liquid.

## Wire the relay output

**Brown** is DC positive, **blue** is DC negative, **yellow** is the signal output, and **black** is COM. For a PLC or MCU input, connect COM to GND for an NPN-style input or to VCC for a PNP-style input.

![PPK-Y28-NC wiring diagram showing brown VCC, yellow output, blue GND and black COM](https://plugplaykit.com/wp-content/uploads/2026/10/nc-wiring.png)
PPK-Y28-NC: the NC contact is on when no liquid is detected and opens when liquid is detected.

![PPK-Y28-NO wiring diagram showing brown VCC, yellow output, blue GND and black COM](https://plugplaykit.com/wp-content/uploads/2026/10/no-wiring.png)
PPK-Y28-NO: the NO contact closes when liquid is detected.

## Liquid and environment limits

- The manual specifies normal detection for dynamic liquid viscosity below 10 mPa·s.
- Detection may be affected from 10 to 30 mPa·s. Liquids above 30 mPa·s are not suitable because material can adhere to the container wall.
- Specified operating temperature is -20 to 105 °C; specified humidity is 5% to 100%; ingress protection is IP67.
- For outdoor installation, protect the sensor from direct sunlight, direct rainwater flow and excessive heat. Keep it clean and inspect it regularly.

## Technical specifications

| Detection type | External capacitive point-level detection |
| --- | --- |
| Compatible installation | Non-metallic pipes ≥11 mm outside diameter or flat containers |
| Supply | DC 5 V, 12 V, or 24 V for the NO/NC versions |
| Relay output | 2 A listed for NO/NC versions |
| Current consumption | 13 mA |
| Response time | 500 ms |
| Level accuracy | ±1.5 mm |
| Cable length | 500 ±10 mm |
| Connector | XH2.54-4P |
| Housing | PC+ABS-V0 |

See the [PPK-Y28 product page](https://plugplaykit.com/product/ppk-y-28-non-contact-liquid-level-sensor/) for the currently available voltage and NO/NC options.