Multiple Services with one eGauge*

EG4xxx and newer Meters Only!

This guide only applies to EG4xxx meters. Legacy EG30xx and eGauge2 meters do not support the Sensor Hub or the EV1000.

Example Wiring Diagram 277/480V Wye and 120/208V Wye

In the following example, the eGauge is monitoring two loads - one on a 120/208V service, and one on a 277/480V service. Note that the Neutral to loads A and B are not shown.

Example Configuration

CT settings and ports used are for demonstration purposes. Use the correct CT models and ports for your installation.

Notes:

  • The service with the lowest voltage should be connected directly to the eGauge, and the higher voltage service(s) should be monitored with the EV1000s. The eGauge can support a phase to neutral voltage of 277Vrms, while the EV1000 can support a voltage of up to 707Vac/1000Vdc, meaning the EV1000 is much more flexible than the meter itself.
  • Sensor Hubs must be powered. Up to 2 hubs can be powered directly from the eGauge via the USB ports on the meter. For installations where more hubs are required or the USB ports are in use (e.g., for Modbus RTU communication) the hubs can be powered directly from a generic 5Vdc power supply or a USB hub may be used. It is preferable to power all sensor hubs from the same 5V source to avoid any common-mode issues that may arise from utilizing multiple power sources.
  • All hardware must be installed in a suitably rated enclosure. eGauge Systems offers several powered enclosure kits which are suitable for this purpose. Most kits feature DIN rails (for mounting the eGauge meter and EV1000s securely) along with a powered receptacle and optional stepdown transformer (which can be used to power the 5Vdc supply for the sensor hubs and/or other supporting hardware).

Example Wiring Diagram 480V Delta and 208V Delta

In the following example, the eGauge is monitoring two loads - one on a 208V Delta service, and one on a 480V Delta service. Since no neutral is present, one phase on each service is effectively treated as a neutral - for the 208V service, C phase is connected to the N terminal, and for the 480V service, C phase is connected to the negative (-) terminals on the EV1000s. In this configuration, only two CTs are required - one on each phase which is not connected to the N or (-) terminal.

Caution!

480V delta services cannot be connected directly to the eGauge! Doing so will damage or destroy the meter. EV1000 sensors must be used to monitor a 480V delta service.

Example Configuration

CT settings and ports used are for demonstration purposes. Use the correct CT models and ports for your installation.

Notes:

  • The eGauge is a Blondel Compliant meter and will measure accurately the total load of a three-wire three-phase service using two CTs when correctly installed as outlined in this document.
  • This method of eGauge installation employs the Two-Wattmeter Method of power measurement which is based on Blondel's Theorem. Blondel's Theorem essentially states that you need one less CT than the number of current carrying conductors in your service to accurately meter the total load of the service. Further research on these topics, if needed is left to the reader.
  • When completing an installation of this type it's particularly important to adhere to the wiring diagram included in this document. CT orientation must be consistent and phase verification should always be performed to ensure that there is no phase mismatch between CTs and their respective Line voltages.

Did you find it helpful? Yes No

Send feedback
Sorry we couldn't be helpful. Help us improve this article with your feedback.