Burbank, CA · February 2025 · Burbank Water and Power / City of Burbank

Seventeen modules, two planes, one system.

A 6.885 kilowatt array on a Burbank house whose roof had no single plane large enough for it. Nine modules went on one face and eight on another, in a day.

Written by the Cali Energy project team · California contractor license 1032379 · Updated September 2026

An odd module count usually means the roof, not the budget. Seventeen modules split nine and eight because neither plane on this house would take the whole array with its required clearances, and the split costs nothing when every module has its own microinverter. What the split does cost is roof penetrations: two arrays mean two sets of attachments, two rail runs and a conduit path that has to cross from one plane to the other, and every one of those crossings is a hole that has to be flashed properly. Burbank roofs are cut up enough that this is the normal case rather than the awkward one.

At a glance

Modules

17 x Hyundai Energy Solutions HiS-S405YH(BK) 405 W

System size

6.885 kW DC

Microinverters

Enphase IQ8MC, one per module

Array layout

Nine modules on one plane, eight on another

Roof

Composition shingle, multiple planes

Balance of system

Combiner panel and alternating current disconnect on the exterior wall

Installation

26 February 2025

Utility / AHJ

Burbank Water and Power / City of Burbank

The story

Seventeen is not a number anybody chooses. It is what a roof gives back after the clearances are taken out of it.

This house has the shape a lot of Burbank houses have: a main ridge, a couple of hips, an addition that changed the roofline at some point, and no single surface big enough to hold a working array with its required perimeter. So Cali Energy laid the array across two of those faces, nine modules on the larger and eight on the smaller, and left the rest of the roof alone.

Splitting an array across orientations is only free if the electronics allow it. With one microinverter under each module, they do: every module converts on its own, reports on its own and is unaffected by what its neighbor on a different face is doing. Put the same seventeen modules on a string inverter across two orientations and the design gets harder and the losses get real.

What the split genuinely costs is roof work. Two arrays mean two sets of attachments, two rail runs to level independently, and a conduit path that has to leave one plane and arrive on the other. Every one of those is a penetration, and a penetration on a shingle roof is not a hole with sealant in it.

Done properly, the flashing plate slides under the shingle course above the hole, so that water running down the roof passes over the top of the flashing and never reaches the opening. Sealant is a secondary defense at the collar, not the thing holding the roof out of the house. Done improperly, the bead on the surface looks reassuring for about two winters.

Everything from both planes comes down to the same wall: a combiner panel, an alternating current disconnect, and the tie into the house. Two arrays on the roof, one system on the wall, one circuit into the service. The whole installation ran on the twenty-sixth of February 2025.

How it ran

One installation day across two roof faces. This timeline reflects this property and this roof.

What we did

• Surveyed a cut-up roof and identified which planes would carry an array with full clearances (C-10).
• Split the array nine and eight rather than forcing one plane to take all seventeen.
• Flashed every attachment and every conduit crossing under the shingle course above it.
• Leveled two independent rail runs on two different faces.
• Mounted and cabled a microinverter under each module position.
• Brought both groups down to a single combiner and disconnect on the service wall.

System specifications

Is your project like this one?

• Your roof is cut into several small faces by hips, valleys or an addition.
• You have been given an odd module count and want to know where it came from.
• You are weighing microinverters against a string inverter on a complicated roof.
• You want to know what a roof penetration under an array actually looks like.

Cali Energy in Burbank

Frequently asked questions

Does splitting an array across two roof faces lose production?

With one microinverter per module, effectively no. Each module converts independently, so a group facing one way does not drag on a group facing another. On a string inverter the answer changes: modules in a string interact, orientation differences matter, and the design has to group and match them much more carefully.

Does Cali Energy install arrays across more than one roof plane in Burbank?

Yes, and on Burbank's cut-up roofs it is often the only way to reach a useful system size. On this house Cali Energy split seventeen modules nine and eight across two faces and brought both groups to one combiner. Eleven Burbank projects are written up on our projects page. Our license is CSLB #1032379.

Why is my system an odd number of modules?

Because the roof decided it. Once fire clearances, vents, skylights and equipment are taken out, what remains is rarely a tidy rectangle, and the module count is whatever fits inside what is left. Seventeen here is nine on one plane and eight on another, which is the roof's answer rather than a compromise on the system.

How should a roof penetration under solar be sealed?

With a flashing plate set under the shingle course above the hole, so water running down the roof passes over the flashing and never reaches the opening. Sealant belongs at the collar as a secondary measure, not on the surface as the primary one. A penetration sealed only with a bead on top of the shingles is a leak with a delay on it.

What this would look like on your roof

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This timeline reflects this property and this permitting path. Updated September 2026.