Energy consumption monitoring is not just a great way for homeowners to better understand their energy usage, it’s also a required element for home energy storage systems. For installers who are growing their business by offering their customers the Enphase Home Energy Solution, the Enphase Consumption Monitoring CT (current transformer) is the equipment that performs this important function. This is a new step in the installation process for some of our installer partners, and in this post we’ll answer some of the most common CT-related questions, like: can I install CTs without an electrical retrofit? (Good news, very often you can.) A little time spent building your best practices ahead of time will spare you and your crew from missed opportunities, and save you costly troubleshooting time later. Keep reading to learn how to build the most efficient consumption monitoring CT installation process.

First, let’s make sure everyone knows what CTs are. In a residential setting, CTs are small devices used throughout the electrical system, on distribution lines and at the circuit level, to efficiently measure electrical current. They measure current by wrapping a secondary winding around a live wire, inducing a secondary current that’s proportional to the current on the primary conductor.

In the Enphase Home Energy Solution, CTs perform both consumption monitoring and revenue-grade production monitoring. Current measurements are used to calculate power and energy, and used by the Envoy to control microinverter and storage system operation. Two consumption CTs must be installed alongside the Envoy-S Metered gateway. A production meter is preinstalled in the Enphase AC Combiner Box and is included with all Envoy-S Metered purchases. The Enphase Production Monitoring CT can’t be replaced with an off-the-shelf production CT, since each one is calibrated to and paired with an Envoy right at the factory. This also means that if you ever need to replace an Envoy-S Metered in the future, you’ll have to replace the CT as well.

Below are recommendations that will simplify and streamline the CT installation process. These tips are broken down into three categories: what to do before the install, during the install, and during commissioning with the Enphase Installer Toolkit mobile app. Continue to the bottom of this post for a detailed description of each step.

Before the install

• Verify that the site can accommodate consumption monitoring
• Find a location for the AC Combiner Box or the Envoy-S near the main service panel

During the install

• Be polarity correct
• Wire CTs into the appropriate terminal inputs on the Envoy and verify measurements with the Installer Toolkit
• Match voltage and current measurements on the same phase

Please think of these tips as a quick reference guide to complement the Enphase Consumption Monitoring CT installation manuals; they’re not a replacement for the installation manuals. At the bottom of this post you’ll find a few more resources, including production and consumption CT installation videos.

Commissioning with Installer Toolkit

• Use the Installer Toolkit mobile app

We recommend that all installers download the app to their Android or IOS devices and log in to Enlighten Manager before going to the job site.

Before the install

• Verify that the site can accommodate consumption monitoring

It’s important to make sure that the home where you’re installing the Enphase Home Energy Solution can easily accommodate the split-core consumption CTs before approving consumption monitoring as part of a project. At some sites, the conductors or the bussing between the utility meter and the main breaker of the service panel are not accessible or do not have adequate space to fit the consumption CTs.

One simple solution is to install consumption CTs directly around the load circuit conductors inside the main service panel. If consumption monitoring cannot be readily accommodated, consider potential modifications to the service wiring. These can include offering your customer a service upgrade with equipment that will accommodate the consumption CTs, or moving the electrical service utility meter socket, making room for the consumption CTs.

See the Enphase technical brief, Assessing a site for installation of consumption monitoring, for a Site Assessment Form to guide you through the process.

• Find a location for the AC Combiner Box or the Envoy-S near the main service panel

To simplify wiring of the consumption CTs, install the AC Combiner Box and the Envoy-S Metered at or near the main service panel.

During the install

• Be polarity correct

Polarity is determined by the direction of the secondary winding. If installed backwards, meter readings that should be positive will instead be negative. CTs are marked with an arrow that must point towards the load. Polarity errors are one of the most common (and easily avoidable) problems with CT installation.

• Wire CTs correctly and verify measurements

CTs must be fed directly into the Envoy-S Metered with correct CT orientation, and they must be connected to the correct terminals on the Envoy.

The Envoy has three terminal blocks: one for power, one for CTs, and one reserved for other uses, such as turning off systems operating in Zero Export mode. Consumption CTs must not be wired to the terminal block on the right side of the Envoy-S.

Enphase Consumption CT Envoy-S Metered Wiring.png

The Envoy cannot properly control the AC Battery if current is measured as part of solar photovoltaic (PV) current, or if the battery is not a load measured by the consumption CTs. Make sure the batteries are installed on the load side of the consumption CTs, not the load side of the production CTs. This is especially important when using a subpanel for PV and storage circuits. Finally, make sure that solar passes through the production CTs.

• Match voltage and current on the same phase

As noted above, consumption CTs will report negative current measurements if installed backwards. They will also report negative measurements (or a zero measurement) if the two consumption CTs are not wired to the correct terminals on the Envoy. The CT that is placed around Line 1 must be wired to Consumption Terminal A in the Envoy, and the CT that is placed around Line 2 must be wired on Consumption Terminal B. For this reason, we recommend marking the physical CT housing and the CT’s sense wire ends with black or red tape. These markings will indicate the appropriate service conductor that each CT measures, avoiding confusion once you’ve pulled wire through the conduit.

Commissioning with Installer Toolkit

• Use the Installer Toolkit mobile app

With Installer Toolkit, you can quickly and easily confirm that CTs are operating and enable production metering. Remember to enable production metering first, then confirm proper metering while onsite. With the solar energy system turned off, confirm that CTs are operating, and make sure your readings are positive. Then enable consumption metering and turn solar on. Select consumption meter type based on whether CTs are wired on load circuits only or on circuits with load and solar production. After five minutes, load-only readings should be greater than readings with load and solar. Test CTs using a known load source, such as a hair dryer at its highest setting.

Resources

Enphase has many resources available to prepare you and your installation team for success with the Home Energy Solution.

Assessing a site for installation of consumption monitoring technical brief

This 13-page document covers CT installations in Eaton service panels and Eaton solar power centers, as well as other challenging scenarios, such as installations with multiple conductors in a single CT, parallel-connected CTs for 400A service, and crowded service panels.

Production CT installation video

This 5-minute video includes step-by-step instructions for installing a production CT for systems that do not use the AC Combiner Box with a pre-installed production CT, and how to verify installation using Installer Toolkit.

Consumption CT installation video

This 8-minute video includes pictures of consumption CT installations, step-by-step installation instructions, and directions on how to verify installation using Installer Toolkit.

Meter installation checklist

This 2-page document helps assure that metering is always wired and configured correctly. It also includes some helpful troubleshooting steps.

When Enphase set out to develop the IQ System, the sixth-generation microinverter system, we accepted a challenge to not only streamline the product for better performance within the smallest package yet but also to streamline the installation process for a quicker and more effective install. For a true measure of the intelligence built into the system, watch an install in action and note some of the ways we are revolutionizing the rooftop electrical install.

The IQ System saves time before you even reach the job site, simplifying inventory management, packing more lightweight microinverters per box to reduce trips up the ladder, and bundling cables so they can be easily slung over the shoulder. It helps that the two-wire Q Cable uses half the conductors and weighs 50 percent less than its predecessor, the trunk cable.

As the IQ System rolls out to distributors in the US and Canada, we credit the installers who have helped install over 13 million microinverters so far, providing critical feedback that Enphase has implemented in the latest evolution of the Enphase technology platform. None of this would be possible without you. Here are some of the ways IQ will improve your installation process.

IQ improves design flexibility

One of the inherent limitations of string inverter systems is the need to always complete a loop in the electrical design. With these DC power systems, there’s no opportunity to branch off to islanded arrays on complex rooftops or in response to on-the-fly design changes.

The field-wireable connectors in the IQ System allow for safe and simple connections from any open connector and the ability to center feed any section of cable up to a 20-amp limit allowing the system to be built as a tree with branches rather than a constricted linear design. The lighter two-wire Q Cable also makes it easier to handle wire management, whether that means fastening cable to rails or to the module frame using standard clips in a rail-less mounting system. To streamline the installation process even further, eliminating field wiring of the microinverter to the module, look for the introduction of  Enphase Energized AC Modules from multiple partners at your distributor this summer.

IQ enables faster commissioning

A new generation of Line to Line power line communications made it possible to remove the neutral conductor from the Enphase cabling system and results in new Envoys and Combiners for the IQ System. This, along with new embedded software, results in a notable improvement in microinverter detection during commissioning. Because the neutral line shares a circuit with other electrical devices in the house, devices that carry a lot of noise on the line, detection could take as long as 15-20 minutes. During beta testing, the IQ Envoy detected a full set of 20 microinverters in less than 5 minutes. Detection might not always be so fast, but we expect the new communications to cut the time in half.

All the process improvements in the IQ System build upon an industry-leading home energy solution that comes with built-in compliance for 2014 and 2017 NEC rapid shutdown requirements and advanced grid functionality that will be needed as utilities move to new standards this year. As grid conditions change, Enphase’s ability to report on each microinverter’s performance and remotely push firmware updates to the field will prevent the need for costly, time-consuming, and unnecessary truck rolls.

Built around a fully integrated technology platform, one that optimizes solar output, storage, and energy management, the Enphase IQ System delivers a new level of simplicity from the moment the solar installation vehicle rolls up to the job site. By reducing the size and weight of the microinverters and cable accessories, we’re helping your crews carry more equipment to the roof in less time.

We called the newest generation of Enphase technology the IQ system because it’s intelligent, for homeowners and especially for installers. And we placed the letter Q in front of our new cabling accessories, because Q stands for quick.

These microinverters have been redesigned to work with power line communications so the 2-wire Q Cable can replace a 4-wire trunk cable, eliminating 50 percent of the weight. The IQ System pairs with a wider range of solar modules rated up to 400 W DC, 72-cell modules. And like previous generations of Enphase technology, the system uses the Enphase Installer Toolkit for rapid commissioning once the installation is complete.

Check out our IQ System installation video to see each step of the process in action. To get your own IQ system installed, click here to find an installer near you.  

By Robin Chen

Enphase AC Battery - Making Storage Simple!

A modular and smart energy storage system with no high voltage DC, requiring minimal effort to install: This is the vision we unveiled for the Enphase Storage System. With alpha and beta sites going up across Australia this year and the product’s launch just around the corner, we are now delivering on our promise.

In Australia, installers are finding it's startlingly simple and even faster to install than the 1 hour 40 minute, four battery install in California that got the industry talking earlier this year. Without the constraints of the metal conduit required by US electrical code, our first-time Aussie installer left that record in the dust.

At sites around the country, trusted Enphase installers have had the chance to install the Enphase Storage System, experiencing its seamless integration with a wide variety of existing solar systems, and they’ve seen for themselves just how fast, safe and simple our system is.

Installed at the home of Enphase staff member, Ben Bishop, the system of three AC Batteries amounting to 3.6kWh in capacity, fits perfectly with a 5kWp rooftop solar system which is also powered by Enphase. Ben’s home now has the complete Enphase Home Energy Solution, maximising his monitoring capability through Enlighten. The installation featured in the video only took 30 minutes to install by one installer, Andy Connolly. Mind you, this was his very first Enphase storage installation.

Piers Morton, Field Application Engineer for Enphase, walks us through the process and the components involved. Enphase’s signature simplicity means there are barely any components, as Piers lays out for us to see - Enphase AC Batteries, backing plates, Envoy-S Metered (if one isn’t already installed at the property), one CT for solar and one CT for consumption* and access plates – no false walls needed - for a practical set up that looks incredible in any setting.

Beyond the physical components, Enphase’s proprietary Enlighten software means there is no need for tedious negotiations with third party software as is notorious in the case of almost all other systems that struggle to integrate with the software of the system’s other components. A storage system should be up and running immediately after installation – homeowners shouldn’t have to think about it. It just works from day one.

Finally, the commissioning of the system itself is intuitive and easy thanks to the renowned Enphase Installer Toolkit which enables quick error checking and confirmation of systems online by installers. Say goodbye to the days of installing a system and having no idea if it is performing properly or not, Enphase does storage the way it was always meant to be – easy.

Thanks to a plug and play philosophy grounded in the design from the start, the Enphase Storage System recognises the home’s existing solar system whether it’s an Enphase system or not, even big ol’ string inverters. Truly seamless, Enphase installers can walk into any job confident that our storage system will fit like a glove with the existing solar and that they will only spend a minimal amount of time on the job – saving them time and their customers money. Further, if a customer decides that they want to scale up their system with more batteries in the future, the decision is much easier and more cost effective – taking under an hour to add more batteries and with no need to pull out existing system components.

Any qualified electrician is capable of installing the Enphase Storage system, and can easily receive Enphase training to ensure highest quality installations. This is because of the unparalleled safety features and quality built into the system, just like every other Enphase product. Committed to making the whole energy storage experience seamless, from start to finish, for both installers and homeowners – Enphase could not be more proud to present the Enphase Storage System as the future of energy management. Hefty expectations have been placed upon any solution for energy storage, but here at Enphase, we’ve been hard at work in the field delivering on our promises.

Ready. Set. Store!

If you’d like to see for yourself how easy it is to install the Enphase Storage System in Australia, contact your distributor for information on how to obtain the Enphase Storage System when it lands on Australian and New Zealand shores in August.

*Number of consumption CTs required may differ in other countries.

From all across the globe, people flock to the Hawaiian Islands year-round seeking its warmth and sunshine to fuel their seaside getaways. But for residents living on the Islands, the sun’s constant exposure provides a thriving source of power where solar energy simply makes sense.

Built in 1907 as one of Hawaii’s oldest and most prestigious all-girl private schools, Sacred Heart Academy’s energy costs have been in excess of $350,000 in recent years, since Hawaii suffers from the highest energy prices. Fed up with the ever-increasing cost of fossil fuel-based energy, Sacred Heart Academy traded in demanding utility electricity prices for a sun-powered alternative that would lower its bills and make the most of the area’s abundant sunshine.

Enlisting the help of Hawaiian Energy Systems (HES) Sacred Hearts Academy installed a 243kW solar array. Prior to the installation, HES performed an energy audit on the campus and proposed a complete lighting (LED) retrofit in addition to the array in order to further reduce the school’s energy cost burden.

To help fund the large project, HES offered a 10-year operational lease (requiring no capital investment), which made solar affordable for the non-profit school.

While initial designs for the project included use of a central inverter, HES uncovered serious design flaws since the inverter’s manufacturing warranty could not withstand Hawaii’s harsh environmental conditions, specifically corrosion. Additional concerns of safety, maintenance, and aesthetics also forced HES to question the use of a central inverter. Ultimately, they designed the system using Enphase M215 Microinverters.

“Enphase provided us with an approach we felt comfortable taking back to our customer,” said Chris Brashear, vice president of Sales and Marketing for Hawaiian Energy Systems, Inc. “Sacred Heart’s Board of Directors was also confident with changing to a solution that now included a reliable, 25-year warranty.”

Ideal for Hawaii’s people-friendly but technology-punishing weather, the Enphase System provided corrosion protection, a longer warranty, advanced production monitoring and a simpler installation design.

Concerns of safety, from a design and installation perspective as well as long-term power production, posed serious issues when it came to bringing solar power onto the school’s campus. With the Enphase System, HES trusted the microinverters’ rooftop location to generate AC power at a safe distance from the students, with no high-voltage components near classrooms or playgrounds. Additionally, due to the smart diagnostic and production monitoring capabilities of Enphase’s web-based Enlighten monitoring software, alerts will be sent to both HES and the school should any problems occur.

Sacred Heart Academy’s new solar array and monitoring system will also be integrated into the school’s curriculum as a teaching tool for renewable resources – a win-win for educators and students.

Comprised of Enphase M215 Microinverters matched with 240BW Centro Solar CP6 modules, the new array reduces energy costs by 33%, leading to significant long-term savings.

System Summary

Client: Sacred Hearts Academy

Location: Honolulu, HI

System Installer: Hawaiian Energy Systems, Inc.

System Size: 243kW DC

Modules: 240W Centro Solar CP6

Installation: 1,048 M215 Microinverters

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