EmonPi Install Guide

The following guide provides an quick overview of how to setup the hardware part of an emonPi energy monitoring system for monitoring up to two AC circuits.

emonpi install digram

emonpi install


Please read the CT installation guide before installing. Your safety is your responsibility. Clip-on current sensors are non-invasive and should not have direct contact with the AC mains. However, installing the sensors will require working in close proximity to cables carrying high voltage. As a precaution, we recommend ensuring the cables are fully isolated; i.e., switch off the power prior to installing your sensors and proceed slowly with care. If you have any doubts, seek professional assistance.

1. CT sensor

  • Clip the CT sensor around either the Line or Neutral cable

  • Connect jack plug into either CT1 or CT2 socket on the emonPi

  • If the power reading is negative, reverse the CT sensor orientation

  • CT sensor cable should not be extended to avoid induced noise

  • For Solar PV install see Solar PV Application page

  • Learn more about how CT sensors work…


The clip-on CT sensors must be clipped round either the Line or Neutral AC wire. NOT BOTH

CT sensor installation

2. AC-AC Adapter

3. DC 5V USB Adapter

  • Plug the DC 5V USB adapter into a power outlet

  • Plug the mini-B USB connector into the emonPi

  • High quality minimum 1.2A power supply recommended

4. Optical Utility Meter LED Pulse Sensor (optional)

  • See Optical Pulse Sensor setup page

  • Connects to emonPi / emonTx via RJ45 connector

  • Self-adhesive velcro attachment to utility meter

  • One optical pulse sensor per emonPi/emonTx

  • Can be used in conjunction with temperature sensors using RJ45 Breakout

5. Temperature Sensors (optional)

6. Installation Examples

home energy

home energy2

The included clips can be used to mount the emonPi / emonTx on a wall.

See Solar PV Application Note for emonPi solar PV install guide & images.

7. Power Up


Ensure all sensors are connected before powering up.

a.) Switch on DC & AC power

b.) Check CT sensor(s) & AC Wave are detected:


c.) emonPi should remember WiFi network and re-connect


8. Shutdown

Optional: Shut down the emonPi, hold down the shutdown button for 5 seconds, then wait 30 seconds for unit to fully shut down.



Unplugging power from the emonPi without following the correct shutdown procedure can result in a corrupted SD card.

9. Video Guide