Tag: "egc"


  10:02:00 am, by Jim Jenal - Founder & CEO   , 1171 words  
Categories: All About Solar Power, Solar News, Commercial Solar, Intersolar 2013

Intersolar 2013 - Enphase Rules with Gen 4

The most important announcement of the show came from our friends over at Enphase Energy who rolled out their 4th Generation microinverter as well as some intriguing upgrades to their Enlighten data visualization web service.  Both have great potential - but will the AHJs go along?

Debuting at Number One

As Enphase prepared to roll-out their new microinverter, they did so against a backdrop of dramatic market news driven by their existing products.  IHS Research  reported that Enphase was the number one inverter supplier in the Americas during 2012, capturing an astonishing 53.5% market share!  Pretty impressive for a relatively young company whose product was dismissed out-of-hand by traditional inverter manufacturers just a few years ago.  Of course, now all of those traditional inverter manufacturers are scrambling to bring their own microinverters to market - a novel twist on the old adage, “First they laugh at you, then they copy you, then you eat their lunch.”

At the same time, GTM Research reported that the Enlighten monitoring system was named “the #1 monitoring provider globally among power electronics vendors for PV markets.” Collectively, the company has shipped over 3.3 million units around the globe - so their new product introduction was an eagerly awaited event.

Enphase did not disappoint - enter the M250.

M250 Takes the Stage

Enphase M250I know what you are saying - that’s an M215!  No, not quite.  For one thing, on the end where it is sitting is a label that proudly identifies it as the M250.  Here’s another clue: the Enphase name and logo are now laser etched into the metal surface instead of the (more colorful) silkscreen used for the M215.  The M250 has more mounting holes than the M215, although only one is needed.  The M250 weighs a tad more than its older brother.

But the biggest difference of all is something the M250 does not have - a grounding lug!  The M250 features what Enphase is calling Integrated Grounding and it means that you do not need to run a Grounding Electrode Conductor (GEC) from inverter to inverter - are you listening, LA Building and Safety?

Ok, so how can this be?  In the M215, the positive conductor was bonded to ground through a Ground Fault Detection/Interruption circuit - which meant that the metal case of the microinverter was also grounded and from that point it needed to be connected back to the system’s grounding electrode via a GEC.  Hence the need for a grounding lug on the M215 and the routing of a #8 conductor (#6 in LA - yikes!) between each unit.  Needless to say, this increased cost (especially in LA) and upped the trip hazard on the roof.

The M250 changes all of that - take a look:

M250 internal wiringNow the solar module is ungrounded and the M250 operates under the NEC provisions - 690.35 & 690.41 - governing ungrounded arrays.  According to Enphase:

[S]ince the M250 isolates the DC conductors from ground, only a simpler Equipment Grounding Conductor (EGC) is required.  The EGC is provided within the Engage Cable system, which connects seamlessly to the AC power system outpout of the microinverter.

Also new to the M250 is the Insulation Monitor (IM), which measures the insulation resistance of the DC circuit with respect to ground… [thus] the M250 detects ground faults in either the DC positive or negative conductor of the PV module.  Together these features offer greater safety than previously possible in any inverter technology.

So, with one stroke, Enphase is doing away with the need for the cumbersome and expensive GEC and eliminating the possibility of disastrous arc fault events!  These are important safety considerations that will surely help the M250 move into more small-to-mid-sized commercial installations.

As with the M215, the M250 can operate in either 240 or 208 (3-phase) configurations - the much sought after 480 volt solution is still a ways off.  The M250 operates at a CEC weighted efficiency of 96.5% at 240 volts (a half percentage point better than the M215) and 96% at 208.  It is intended to operate with 60-cell modules up to 300 Watts which makes it a fine choice for LG’s NeoN modules.  The M250 is actually rated at 240 Watts continuous (250 Watts peak, hence the product designation) which means that you can install 16 M250s on a single 240 volt branch circuit, protected by a 20 amp breaker.

Envision This

Although the M250 rollout was the big news, Enphase also debuted a major rework of their Enlighten monitoring system.  Although still in beta, the new  visualization service - called MyEnlighten - is intended to take the large amounts of data gathered by the Envoy system and turn it into something more user friendly.  We signed up for the beta and here’s how it looks:

MyEnlightenInstead of seeing a panel-by-panel display - a visualization that will still be available to installers for trouble shooting - the new display lets you see how your system is performing overall and over time.

The bottom row of blue squares represents the present month with each square a given day.  The lighter the shading the more energy that was produced that day.  What jumps out is the black square - that represents today’s energy taken at 7:00 a.m. and hence very little to show so far.  The other two darker blue squares represent days when clouds and even rain were present here in Pasadena - and the system tells you what the weather was that day so you have the proper context in which to evaluate your system’s performance.

The display also allows you to present a variety of different energy equivalents - here we have chosen to compare our energy production against what it takes to illuminate the Eiffel Tower.  On July 16, this system produced enough energy to light the Eiffel tower for 95 minutes - and over the lifetime of the system it has produced enough energy to light it for 46 nights!

The new system integrates with social media and allows system installers to include information about the system and their company helping to make it a co-branded marketing tool as well as an educational platform.  We are looking forward to sharing this system with our clients.

Enphase’s Intersolar performance argues that the company - far from resting on its laurels, or its number 1 position in the market share rankings - is working hard to build on its explosive growth.  It remains far ahead of its johnny-come-lately competitors and without a superior product from them, why would anyone jump ship from Enphase?

In our view, Enphase has only two real threats facing it: a sudden batch of product failures and the dumping of cut-rate inverters from China into the US market.  As to the former, Enphase is doing all that it can to prevent it from happening, noting that more than a million product testing hours went into the new M250.

As to the latter, there is little that Enphase can do and it raises the question: what will we as an industry learn from our experience succumbing to the siren song of cheap solar modules?  That is a topic for another day.

This day, and Intersolar, belonged to Enphase without even having a booth - a dollar savings that will go straight to their investors’ bottom line.



Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

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