Technical Brief for Installation of Consumption Monitoring

ManualsBrandsEnphase Energy ManualsSolar & Wind PowerEnphase Consumption Monitoring for Envoy

Table Of Contents

Assessing a Site for Installation of Consumption Monitoring

TECHNICAL BRIEF

Assessing a Site for Installation of Consumption Monitoring

For North America and Latin America

About the Enphase Envoy-S Metered

The Enphase Envoy-S Metered™ communications gateway enables performance monitoring and remote

software and firmware updates of an Enphase Microinverter System. In addition, the Envoy-S Metered

provides revenue-grade production data and allows for the monitoring of a site’s energy load, thus offering

significant advantages over other PV system monitoring equipment. Users can access energy production

and consumption data through Enphase Enlighten™ cloud based monitoring software.

To perform both revenue grade production and energy consumption monitoring, the Envoy-S Metered

requires current transformers (CTs). This document provides guidance on assessing a site’s potential for

monitoring and includes additional tips to help with CT installation. For assistance with revenue grade

production monitoring, please refer to the Enphase Envoy-S Installation and Operation Manual.

Enphase recommends that an installer or site assessor verify that the site can easily accommodate

consumption CTs before approving consumption monitoring as part of the project.

The Envoy-S installs in most single-phase photovoltaic systems. For sites where consumption monitoring

cannot be readily accommodated, this document provides a list of potential modifications to the service

wiring to allow for consumption monitoring.

About Consumption Monitoring

Consumption monitoring is not required for a typical Enphase System installation, although consumption

data is useful in helping a system owner better understand their energy usage related to their Enphase

System production. Determining energy consumption is critical for homes that require zero export of

Enphase System production to the grid or for potential customers of the Enphase AC Battery™.

Site energy consumption and production shown in MyEnlighten

• Dark Blue: Solar production exported to grid

• Light Blue: Solar production consumed on site

• Dark Orange: Energy purchased from the utility

• Light Orange: Consumption offset by solar

Consumption Current Transformers

Consumption monitoring requires installation of two consumption monitoring CTs on the main service

conductors feeding the site. At some sites, the conductors or bussing feeding the main breaker of the service

panel are not accessible or do not allow for adequate spacing.

Summary of content (13 pages)

PAGE 1
TECHNICAL BRIEF Assessing a Site for Installation of Consumption Monitoring For North America and Latin America About the Enphase Envoy-S Metered The Enphase Envoy-S Metered™ communications gateway enables performance monitoring and remote software and firmware updates of an Enphase Microinverter System.
PAGE 2
Installing Consumption CTs Site Assessment Form When considering consumption monitoring, first determine if the split-core consumption CTs can be readily installed around the service conductors or busbars. If the consumption CTs cannot be easily installed on the service panel, additional electrical wiring may be required to prepare the site. To complete the site assessment form, an electrician may need to remove electrical enclosure covers. This must be performed by a competent individual.
PAGE 3
Installing Consumption CTs Circuit Detail Form Use this form to calculate the total cross sectional area of all load conductors. Breaker Ampacity Line Conductors Conductor Type and Size L1 – Black Conductor Area L2 – Red Conductor Area Example (Oven) 50 1 and 2 2 - #6 THWN 0.0507in2 0.0507in2 Example (Lights 1) 20 1 1 - #12 THWN 0.0133in2 Example (Lights 2) 20 2 1 - #12 THWN Circuit Description 0.0133in2 Total CT 60% Fill Rating (Maximum Fill Rating) 3  2016 Enphase Energy Inc.
PAGE 4
Installing Consumption CTs 200A Consumption CT Dimensions The split-core consumption CTs open and clamp around an existing conductor or busbar without rewiring. The CTs accommodate conductors up to 4/0 RHW, 350MCM THWN, 350MCM XHHW, or busbars up to 0.75 inches, which is adequate for 200A services. 4  2016 Enphase Energy Inc. All rights reserved.
PAGE 5
Installing Consumption CTs Location of the Envoy-S Metered To simplify the wiring of the consumption CTs, locate the AC Combiner Box and/or Envoy-S Metered at or near the main service panel. If you are installing the Enphase AC Combiner Box, the Envoy-S Metered comes with the production CT and the Envoy-S prewired for power.
PAGE 6
Installing Consumption CTs Installing CTs in Eaton Service Panels / Solar Power Center In many of the Eaton Service Panels and in the Eaton Solar Power Center panels, it may appear that the consumptions CTs fit on one of the service entrance conductors, but not on both of the service entrance conductors or busbars. However, if you test the voltage across the main breaker, you will find that the line conductors are rotated inside the circuit breaker.
PAGE 7
Installing Consumption CTs Installing Parallel Connected CTs for 400A Services and Crowded Service Panels In many scenarios, it is difficult to install multiple conductors through a single CT, because some of the conductors may enter from the bottom of the service panel and others enter from the top of the service panel. Also, some service panels have 400A services that are provided by a set of two 200A conductors and parallel-connected 200A circuit breakers.
PAGE 8
Installing Consumption CTs The terminals of the Envoy-S are rated for two #18 CT wires on a single terminal or one #14-#16 conductor. Two #18 CT wires on a single terminal Concerns around installing parallel consumption CTs: • • • • • • • It is easy to make wiring errors It is critical to ensure that all of the conductors that pass through the line 1 CT terminate at circuit breakers on the black/line 1. Line 2 conductors must pass through the line 2 CT.
PAGE 9
Installing Consumption CTs Calculating Whether Multiple Conductors Fit Within a CT Use a conductor fill calculation to determine if a given number of conductors can be installed within a single CT. The NEC allows for a 60% fill calculation for conduit sections no longer than 24 inches. A 60% CT fill calculation provides a conservative basis for calculating the number of allowed conductors. Enphase consumption CT – cross-sectional area 100% Fill Enphase consumption CT 520mm2 0.
PAGE 10
Installing Consumption CTs Example Calculations for a Service Panel Suppose a service panel contains the following line conductors: Breaker Ampacity Line Conductors Conductor Type and Size L1 – Black Conductor Area L2 – Red Conductor Area Electric heating 50 1 and 2 2 - #6 THWN 0.0507in2 0.0507in2 Oven 50 1 and 2 2 - #6 THWN 0.0507in2 0.0507in2 Stove top 40 1 and 2 2 - #8 THWN 0.0366in2 0.0366in2 Air conditioner 30 1 and 2 2 - #10 THWN 0.0211in2 0.
PAGE 11
Installing Consumption CTs Retrofitting the Electrical Service for CT Installation In the case where CTs cannot be installed on the existing service conductors, additional wiring may allow the installation of consumption CTs. One option is to request access to the utility’s service conductors, and then connect the CTs in the utility side of the service panel. Another option would be to work with the utility to relocate the main service meter in a separate enclosure from the main service panel.
PAGE 12
Installing Consumption CTs Monitoring with the Installer Toolkit Mobile App The Installer Toolkit allows you to monitor and troubleshoot consumption monitoring once it has been configured. You can view production and consumption data from the Installer Toolkit Overview page, as long as the phone and Envoy-S are paired in AP Mode. This data is near real-time consumption data that updates every 60 seconds.
PAGE 13
Installing Consumption CTs Viewing Sites with Consumption Monitoring Actual Sites with Consumption Monitoring Enphase allows access to actual sites that use consumption monitoring. You can view these using the demo login info provided below: https://enlighten.enphaseenergy.com/pv/systems/67?osv=1 (Eich Residence) https://enlighten.enphaseenergy.com/pv/systems/283776?osv=1 (Brown Residence) You will be prompted to log in. Use the following email/password: • • email: demo@enphase.