A weatherhead is a waterproof cap that protects a service drop – the point where overhead electric wires from a power pole enter a building, usually via a hollow metal pole called a service mast. The weatherhead is shaped like a hood, with one side sloping down so that moisture will flow off and away from the connection. The electric wires enter the mast through the underside of this hood, typically through watertight rubberized gaskets.

While weatherheads are designed to stand up to wind, rain and snow, they are vulnerable to impact from solid objects like tools or ladders. Also, especially if the fittings are older, there may be fine cracks in a gasket so that it will still keep out moisture from above or to one side, but may let in water under pressure from below – as from a hose or sprayer. And, of course, if you slip and fall against the service mast, pulling wires loose, you risk being severely shocked or electrocuted.

If you’re going to be working on or around a roof, locate the weatherhead and the power lines that feed into it. Then plan your job so that you can keep all workers, tools, materials and equipment at least 10 feet away. If that’s not possible – say, you’re re‑roofing the entire house or replacing the gutters in that area – contact National Grid at 1‑800‑642‑4272 (New York) or 1‑800‑322‑3223 (Massachusetts) well in advance. We’ll de‑energize the service wires or make other arrangements to help you work safely.