South Campbell Avenue 7kW Grid Tied Solar System in Northern Arizona

South Campbell Avenue Grid Tied Micro-Inverter System


The array for the South Campbell Avenue System, showing the structure that houses the system.

The South Campbell Avenue system is a Grid Tied System that employs 24 Enphase S280-60, micro-inverters. This system will produce 10,934kWh over the course of a year. The monthly kilowatt hour production is plotted in the graph at the bottom.
There are trees to the southeast of the system, which will cause shading in the morning, for part of the year. Micro-Inverters limit the affect of the shading by providing a Maximum Power Point Tracker (MPPT) for each panel and making each panel a parallel source circuit in a system branch circuit. If one panel is shaded, only the power from that panel is lost. The power from any other panel is not affected.

The South Campbell Avenue System includes 24 panels (24 Micro-Inverters) in 2, 20 amp circuits.

A 20A circuit of the S280 micro-inverters can contain a maximum of 14 units. This system employs 2 circuits of 12 inverters. The circuits are run to a common roof penetration, over the eave. Penetrating over the eave prevents the solar system from producing potential leak sites over the living space. The conduit and circuit combiner can be seen below.

This is the array combiner, combining the strings of Enphase Micro-Inverters, along with the meter socket and AC Disconnect.

In the combiner, multiple PV circuits are combined into a single circuit to run off to the main service panel. An Enphase Envoy S communications unit is also contained in the combiner. The Envoy sends information from each inverter to a webpage where the Owner, Installer, and Manufacturer can monitor the production of each unit. If there is a warranty issue with any of the inverters, the manufacturer will be notified, automatically, and a replacement will be sent to the installer.

At the location of the South Campbell Avenue system, accounting for equipment inefficiencies, wire loss, typical environmental conditions, and the available solar resource, the kWh production of the the system is plotted, for each month.

A Grid Tied system, like this, currently costs approximately $20,000.00. After the 30% Federal Tax Credit, and the $1,000.00 State Tax Credit, the initial cost of the system is a little under $13,000.00. If the electricity rates continue in their current trend, this system will pay for itself in less than 7 years.