Measure the roof before a module hits the page. Newton Massachusetts residential solar design that runs glass to the ridge will not match the permit layout. Subtract the ridge setback and the pathways first. Then place modules. The sales PDF is a different drawing, and the SMART application should follow the permit sheets, not that PDF.
Athol Energy draws the permit set and stamps what needs a stamp. The installer sells, files, and builds. We do not treat the sales layout as the permit layout.
Measure the roof before you mark inches
Start with plan-view roof area. That is the area a reviewer sees looking down, not the sloped surface you would walk. The sloped number makes the roof look larger and makes the array look like a smaller share of it. The checklist uses plan-view. Write that area on the roof plan before you talk about percent.
These figures come from Massachusetts fire plan-review checklists based on 527 CMR 1.00, the Comprehensive Fire Safety Code. That code is based on NFPA 1, 2021 edition, with Massachusetts amendments. It has been the state fire code framework since the December 9, 2022 edition, with the amendment package effective May 12, 2023. The sheet does not need the history. It needs the percent test and the inches that follow from it.
On a one- or two-family roof that is not sprinklered, an array up to 33 percent of the plan-view roof area keeps 18 inches on each side of a horizontal ridge. More than 33 percent, and the setback is 36 inches on each side. Both sides. A dimension on one side only does not cover the other side of the same ridge.
Sprinklers and the flat-roof exception
If the house is sprinklered, 18 inches holds up to 66 percent of plan-view area. Above 66 percent, use 36 inches on each side of the horizontal ridge. Say on the sheet whether the house is sprinklered. If you do not know, ask before you pick 18. Guessing the smaller band on an unsprinklered house is how a layout gets redrawn after review.
A roof pitch of 2:12 or less has no ridge setback. Note the pitch. Take that exception only when the pitch qualifies. A steeper roof does not get to borrow it.
Newton Massachusetts residential solar and the plan-view percent
Do the percent before you fall in love with a module count. Array area divided by plan-view roof area, then compare with 33 percent, or with 66 percent if the house is sprinklered. The result picks 18 inches or 36 inches. Mark that band on each side of the horizontal ridge. Modules do not enter the band.
A sales layout drawn to the ridge hides this test. It shows modules in the strip the checklist keeps clear. When permit design pulls those modules out, the count drops. That drop is not a drafting error. It is the setback doing its job. Tell sales the permit count before the customer sees two different pictures of the same roof.
Cambridge is a different city. Cambridge solar setbacks live on their own page. Do not copy that page onto a Newton roof, and do not expect this page to answer a Cambridge review. Newton work is the plan-view percent on this roof, in this order: measure, mark 18 or 36 inches, then place modules.
The numbers are state fire-code items used on municipal checklists. They are not a special ordinance of Newton. The local fire prevention office can add a note. If they do, revise to that note. Do not apply the Town of Weston's extra street-face rule here.
Pathways come out of the count too
Ridge inches are only half of what you subtract. For one- and two-family dwellings the checklist also wants pathways:
- At least two pathways, 36 inches wide, from gutter to ridge. One of them is on the street or driveway side.
- Each roof plane that has PV needs a 36-inch pathway on that plane, on an adjacent plane, or straddling the two.
- Pathways should avoid vent pipes, conduit, and mechanical equipment, so a roof ladder can lie flat.
Mark those strips on the roof plan before you drop a module. A module that sits in a pathway is not a permit module. If the path straddles two planes, the drawing still has to show a 36-inch pathway, with a dimension a reviewer can read. Label the street or the driveway so it is obvious which path is the arrival side.
If a vent, a conduit run, or mechanical equipment lands in the strip, the ladder cannot lie flat. Move it on the plan. Dimension 36 inches on the line. A legend that says keep clear, with no number, fails the same test.
The roof attachment layout has to follow those strips. Rails and conduit do not get to reclaim a pathway after the array was shrunk to fit. Draw the hardware in the remaining roof, then count modules again.
The SMART application follows the permit layout
SMART Program Year 2026 applications are open January 1, 2026 through December 31, 2026. Facilities at or under 25 kW AC, and behind-the-meter facilities over 25 kW up to 250 kW AC, are not subject to the 600 MW annual cap for Program Year 2026. That cap rule does not pick your module layout. The fire-code setbacks do.
File the SMART application from the permit layout. The modules inside the ridge band and the pathways are not on the permit roof, so they should not be the facility you describe on the application. A sales PDF drawn to the ridge will overstate the array. When the permit comes back smaller, the two filings disagree. Match them before either one goes out.
The Department of Public Utilities approved company-specific SMART 3.0 tariffs on July 8, 2026, after which DOER could issue Final Statements of Qualification. Do not put a dollar rate on the drawing. A Final Statement of Qualification, if DOER issues one, should describe the array on the permit sheets. The plan-view percent, the ridge dimension, and the pathway dimensions belong on that roof plan so the SMART outline and the permit outline are the same.
Confirm the bill before you pick a form
Newton electric accounts are commonly Eversource. Confirm the bill. The interconnection form follows the utility, not the city line. A Newton street address does not by itself choose the form. Read the company name on a current bill and use that name on the one-line and on the request.
If the bill is not in the folder, do not title the one-line from habit. Commonly Eversource is not the same thing as always Eversource. Interconnection drawings should name the company the customer actually pays. Athol will match the one-line to that bill. We do not file the request as the customer.
What the permit sheets have to show
The roof plan should let a reviewer redo the math: plan-view area, the percent, sprinklered or not, pitch, the ridge inches on each side, and two 36-inch pathways with one on the street or driveway side.
Residential solar drawings are where that roof plan lives. Permit design turns the marked-up roof into a set the installer can file. Massachusetts solar design applies the same state checklist without pretending Newton invented a private ridge rule. Measure this roof, mark 18 or 36 inches, then place modules. Build the SMART application from that placement.