The Planning Board Thursday night will open a public hearing into a proposed new section of the zoning bylaw that would regulate outdoor lighting in town. The board will also consider proposed minor engineering changes to previously approved site plans for three developments. The changes are being requested by Nordblom for the planned Wegmans supermarket at 53 Third Ave. in Northwest Park; by the Northbridge Companies for its planned assisted-living facility on Network Drive in Northwest Park; and by Burlington Crossing Realty Trust for the renovation and expansion project that Keurig plans to carry out at its future location at 43-63 South Ave. The board will resume a hearing into a proposed 38,000-square-foot mixed-use development at 90 Middlesex Turnpike. RC Trust seeks a special permit for the project. The board will also open a hearing into a request by Turner Construction for a special permit to store diesel fuel for a proposed generator at 5 Wayside Road , and a minor engineering change to its site plan to allow for the generator. It will hold a hearing on an application by Terry Avenue LLC for site plan changes to allow for an expansion of the Storage Unlimited building at 17 Terry Ave., and facade improvements. The board will hold a hearing on a request by Peach Orchard Place LLC to revoke its previous denial for subdivision approval for a new road for the 60 additional apartments and the single-family home it wants to build at Beacon Village, off Beacon St., according to Don Benjamin, the town’s assistant planner.