2-wire (Hot to Neutral) electrical systems can be 120 volts, 240 volts, or commonly in foreign countries they can be 230 volts (Hot to Neutral).  Metering of these systems can be done with any of our Omnimeter models.  Metering 120 volt 2-wire systems can also be accomplished using our EKM-XDSE or EKM-15E, but the instructions below will focus on our EKM Omnimeters.

The images and diagrams shown here are in no way exhaustive. These are just a few examples of how you might set up a metering system, and are simply intend to show what is possible. These are the options that you might consider for your metering setup:

  1. Do I want to read the meter(s) locally with computer or do I want a cloud based solution (EKM Push).
  2. What diameter and amperage rating will I need for the Current Transformers? You will need one CT for your 2-wire single phase electrical system.  
  3. Do I need to go wireless?
  4. Do I have a need to daisy chain multiple Omnimeters together? This allows you to connect multiple Omnimeters in series, which can then be connected to a single communication device.

The answers to these questions should help you narrow down your options and allow you to select the products that you will need for your particular application.

Connection Instructions:

For a 120 volt 2-wire system or a 230 volt 2-wire system (1 hot, 1 neutral) you will only need to use 1 CT.  You will have 1 hot wire (commonly black or red) and a neutral wire (usually white).  When you measure the voltage between these 2 wires you will get 120 volts, or 230 volts for those systems not in the U.S.

  1. Turn off power to the sub-panel.
  2. Connect the hot line voltage reference wire to port 7 on the Omnimeter and the Neutral line voltage reference wire to port 10 on the Omnimeter.
  3. Connect the CT so that the hot wire passes through it and the arrow on the CT points towards the load.  
  4. Connect the CT black wire to port 1 on the Omnimeter and the CT white wire to port 2 on the Omnimeter.  

This video tutorial provides an example of how to install an Omnimeter Pulse v.4 on a 120/240v electrical system. You can use this video to infer how a single phase, two wire installation might go. The only absolute difference is that there will only be one CT and one voltage reference wire:

Below are diagrams showing each Omnimeter model wired to a single phase 2-wire no-neutral electrical system, while also being RS-485 hardwired to a Push3 gateway (A to A, B to B).

Omnimeter I v.3:

Omnimeter II UL v.3:

Omnimeter Pulse v.4:

Omnimeter Pulse UL v.4:

See this model for reference of how to properly connect an Omnimeter to a 2-wire system:

Here is a link to a movable 3D model of the above diagram that you can use to see details of any side:  2-wire Single Phase EKM Omnimeter 3D Model

Please note that most of the diagrams above show a wireless connection using 485Bee Zigbee radios. The 485Bee radios are an option that should only be considered if a hardwire connection is not possible, as they will add significant cost and complexity which is not necessary in all systems.