The case for microinverters in commercial installations

A jointly created opinion piece

Let’s face it, our industry is driven towards cost reduction at every turn. Whether we are competing against volumetric utility rates, other contractors, or our own sales goals, we’re under pressure to drive our costs down.

 

We are all for improvement. And when we hear about Natural Gas Peaker Plants being cancelled in favor of solar, wind, and energy storage due to economics, we could not be prouder of the industry we’ve bet our careers on.

 

What is concerning is the compounding complexity of installing more advanced technology, faster and under the most stringent code requirements in the industry’s history. Eventually, the chickens will come home to roost. That may be in the form of O&M nightmares that damage our reputation and margin. And it could be in the form of failures that cause property damage and create headlines that shed doubt on the industry.

 

Our argument? Microinverter solutions such as Enphase can significantly reduce complexity and potential for installation errors on commercial systems.

 

Let us start with integrated, module-level AC rapid shutdown. An inherent benefit of Enphase architecture and compliance with IEEE 1547. This means meeting NEC 2017 requirements right out of the box. No additional components to buy. No concern about communication between an inverter company and a module-level technology company.

Another benefit of locating the inverter at the module level is the elimination of High Voltage DC Arc Faults. By design, DC voltage will be limited to the Voc of the module connected to the microinverter. This means ten to twenty times lower DC voltage on the roof than competing solutions.

 

Next, let us consider the IP67/NEMA6 rating. Enphase IQ7 model microinverters can be submerged in water and operate under load, underwater. Rain, snow, flooding, you name it… they are designed to keep moisture out.

 

Why is this relevant to reduced complexity and installation errors?

 

Most inverters need to be opened and/or modified on-site during installation and maintenance. This may include removing a cover, removal of knockouts for the conduit to enter and exit, adjusting fuse holder and bus-bar screws, and replacing fans.

This means sensitive electronics and current-carrying conductors are exposed to the elements and human errors. Even the best electricians make mistakes when working in 100+ degree heat and under a deadline.

A sealed inverter does not just keep water out. It also prevents capable (and not-so-capable) contractor hands from entering the inverter enclosure. It also means a more reliable product that needs to be replaced less often. And when a replacement is needed, it can be done with one person, a few tools, and no lift.

 

Finally, the Enphase Q-Cable cabling system. These cables connect inverter to inverter in AC branch circuits but ultimately provides a plug-and-play solution that eliminates reverse polarity wiring and speeds up installation times.

 

In summary, a sealed inverter that cannot be modified or field repaired, in combination with the integrated rapid shutdown and plug-and-play cabling will decrease complexity, errors, and O&M margin erosion. Add in the elimination of High Voltage DC arc faults and the inability of water to penetrate the casing and you can rest assured you sold your customer one of the safest and most reliable systems money can buy.

 

Jeff Wolfe

C&I - Business Development Manager

 

Luc Collin

C&I – Sr. Field Application Engineer