eGauge Installation

Covers topics related to the physical aspects of eGauge installation.


The EG4xxx series meters are capable of monitoring up to 7 single-phase units (EG4015) or 15 single-phase units (EG4030) with a single meter. Single-phase units require 2 CTs each, one for each phase.

Please visit for an overview of the physical installation and configuration process.

Example Wiring Diagram

Below is an example diagram of an EG4015 measuring 7 single-phase units on a distribution panel.

Ensure the meter's L1, L2, and L3 breakers are the same phases as the panels L1, L2, and L3 phases, or a phase-mixup will occur and recorded data will be incorrect. See this article for more information on phase checking.

The meter in the diagram shown below does not reflect the physical layout or dimensions of the eGauge meter.

Panel layout and installation will vary. The meter must be configured in software to match the physical installation before any data will be recorded.


A diagram showing the CT connections for the last 3 units from above may be found here.

Example Configuration

Sensors (CTs)

In most submetering installations the same model CT will be used on all breakers. In this example, all CTs are set as 100A 20mm AccuCTs. If using CTid CTs, please click the blue CTid button to configure CTid sensors.



Registers define the data points the Gauge meter records. Each power calculation consists of a sensor input (S1, S2, S3...) that has the CT, and the voltage phase it is on (L1, L2, L3). Since each single-phase unit uses 2 CTs, there are 2 power calculations in each register added together to define the total usage of that unit.

Note, while the phasing pattern for units is typically staggered as L1 and L2, then L3 and L1, then L2 and L3, and so on, in the above example this changes with Unit 5 because the breakers for Unit 5, 6, and 7 begin on the right-hand side of the panel.



Panel phasing and eGauge installation

Correct phasing (associating a CT with the correct voltage reference) is a critical component of the eGauge installation. Ideally, phasing should be verified using a handheld multimeter to determine the phase of a conductor monitored by a given CT. Generally this is less of a concern for split phase services, but three phase services will encounter severe accuracy issues if phasing is incorrect.

eGauge technical support can offer assistance with determining correct phasing. However, correct phasing cannot be guaranteed in this manner. Correct phasing requires on-site verification, performed by a licensed electrician. eGauge does not suggest phase testing or opening electrical panels for any reason unless qualified to do so. Below is a description of panel phasing and a diagram, and for further reading a document with additional examples is below.


The most common installation issue with retrofit energy metering is known as a phase mix-up, which will cause invalid power readings and often lower-than-expected power factor. In addition, the power readings may be the opposite of expected polarity (based on CT orientation).

In typical U.S. split-phase and three-phase panels, breakers alternate sequentially from top to bottom; three-phase services go A, B, C, A, B, C and so on. Breakers horizontally parallel are on the same phase; the top breakers on both sides are phase “A,” the next set of breakers are phase “B,” and so on. When monitoring incoming feeds of a 120/208-V panel, it’s generally expected for CT1 to measure phase A (black), CT2 to measure phase B (red) and CT3 to measure phase C (blue).

Often, the first unused or available breaker slot for a retrofit meter installation is not on the A phase, but instead may be on the B or C phase. For example, if the meter’s L1 voltage input is on a breaker using phase B, then L2 will land on C and L3 on A. Now there is an offset between the system’s true L1 and meter’s designated L1.

If the CTs are installed with CT1 on A (black), CT2 on B (red) and CT3 on C (blue), there is now a phase mix-up because CT1 is on the system’s A phase but the eGauge’s L3 phase. This issue is more likely to occur when the meter is not close to the CTs, so voltage connections cannot be directly traced between the eGauge and the panel.

The best method to confirm phasing is correct is to use a handheld voltmeter set for the AC voltage of the system. Place one probe on the L1 voltage terminal of the eGauge and the other probe to the conductor CT1 is around. A reading of 0 VAC indicates it is the same phase and CT1 is truly monitoring L1, while a reading of 208 V (or other phase-to-phase voltage) indicates they are different phases and CT1 is not on L1. This method can be used on any electrical service.

The eGauge Channel Checker tool and oscilloscope waveform viewer may be used to help identify phase mix-ups. If a phase mix-up is found, the software can be configured to apply the CT to the correct line without having to physically relocate the CTs.

We recommend this method be used in addition to other commissioning techniques on all retrofit energy meter installations to ensure correct readings and avoid problems that may require revisiting and inspecting the installation.

Extending the length of the CT leads

CTs may also be extended without splices or soldering using the eGauge Sensorhub as a CT extension kit.

Do not use wire nuts to connect CT extensions. Wire nuts will degrade and interfere with the low-voltage CT signals.

Split core CTs can be extended with twisted pair wire to cover much longer distances. STP (shielded twisted pair) is recommended, as it will reduce noise and interference. If you need to extend a CT wire farther than approximately 100 ft (30m), voltage drop must be taken into account and a larger gauge wire should be used.

Note that CT leads longer than approximately 100ft (30m) can cause a decrease in accuracy. This is especially true of CTs with high maximum amperage ratings which are reading extremely low amperages. 

eGauge typically recommends 22 AWG to 18 AWG 600V rated CAT5 Ethernet cable, as it is generally easy to obtain and can be used to extend up to 4 CTs. However, any shielded twisted pair wire with appropriate insulation and wire gauge can be used. Be certain to use twisted pair wire that is appropriately rated for the location and panels it will be run in.

Connections should be made with solder and heat shrink tubing, or butt connectors. Wire nuts must not be used to extend CT leads.

Please see the CT selection guide for full details regarding CTs.

​Monitoring 480V and 600V delta systems

The eGauge is capable of directly measuring voltages up to 277V L-N (480V L-L). In the case of a delta system with no neutral, the maximum phase-to-phase voltage is 277V as the "N" terminal of the meter has one of the line voltages connected.

A 480V or 600V delta without a neutral may be monitored by the eGauge using EV1000 High Voltage Sensors.

The below diagram shows a 480V delta system. 600V delta systems may be measured in an identical manner.



EV1000 high voltage sensors are CTid-compatible. See this article for instructions on configuring CTid-compatible sensors.

The register configuration for the example shown above is simply S1xS4 + S2xS5. Note that your configuration may differ depending on which ports are used.


Proper CT/phase pairing is required for accurate readings.


Protecting the eGauge with inline fuses

As long as it is permitted by code, an inline fuse can be used to protect the eGauge. We suggest using a quick disconnect fuse block to allow the eGauge to be power cycled for troubleshooting if needed. A rating of 15A is suggested, but a larger or smaller fuse (between 5A and 50A) is also acceptable.

It is important to provide the end user with a reliable means of power cycling the eGauge.  This is generally the first step in any sort of troubleshooting process.  A fuse block which exposes the end user to line voltages is generally not adequate.

Connecting directly to the eGauge


The eGauge is most commonly accessed through the proxy server, using an address in the form or The eGauge may also be accessed via its IP address or hostname over the local network (commonly done to make configuration changes). However, both cases rely on a router or other networking hardware to establish a link between a computer and the eGauge.

In cases where it is not practical to connect the eGauge to a router, it is possible to connect to the eGauge directly using an Ethernet cable and a laptop or desktop computer with an Ethernet port. Connecting directly is often used for troubleshooting purposes, applying a device configuration prior to installation, or when leaving a device at a remote location where internet access isn't available. Tablets used in conjunction with USB to Ethernet adapters are not officially supported, but may work.

Introduction to connecting directly

By default, the eGauge will attempt to obtain an IP address and associated information through a service called Dynamic Host Configuration Protocol (DHCP). If you cannot or do not wish to run this service on your LAN, or there is no LAN or network environment, the device will default to using IP address, so the device can be accessed at:

The eGauge can be directly connected to a laptop or computer via an Ethernet to the built-in Ethernt port (EG4xxx and EG30xx), or to the HomePlug adapter (EG301x or older model eGauge2). This is often useful in environments with no local network, or where access to the network is restricted. In these scenarios, the eGauge can be configured and commissioned locally and directly; at a later time the eGauge can be retrieved and the data can be viewed and exported. On EG4xxx meters, data can also be exported to a USB thumb drive.

Please refer to the proper walkthrough for setting up your device to communicate with the eGauge, based on the operating system of the computer used to connect. These instructions assume that the eGauge is configured to use DHCP (not a static IP address).

Microsoft Windows 10

Microsoft Windows 8

Microsoft Windows 7

Mac OS X (tested on Mountain Lion 10.7)

Linux/Unix (advanced)

For advanced/experienced users:

Connect a computer to the same network as the eGauge, or directly to the HomePlug adapter or EG30xx/EG4xxx Ethernet port as stated above.

On the computer, set an IP address of, with a netmask of Connect to the eGauge via device hostname, default IP of, or current static IP (if set). Note that a different IP address may need to be used on the computer if the eGauge's static IP address is not in the range. 

Microsoft Windows 10

1. Open the Start menu and click the Settings icon (gear).


2. In the "Find a Setting" search bar at the top of the page, type "control panel" without quotes.


3. Once in the control panel, click "Network and Sharing Center".