The Overhead Electrical Service:
Mast, Weatherhead, Drip Loop, Tree Limbs and Who Owns What

The parts, and who generally owns them

From the pole to the panel, an overhead service looks like this:

• The service drop. The wires from the utility pole to the house. Generally owned and maintained by the utility.
• The point of attachment. A bracket or insulator on the mast or the house that the drop hangs from.
• The drip loop. A short sag in the wires before they enter the weatherhead.
• The weatherhead. The cap on top of the mast that the wires enter. It’s shaped to keep rain out.
• The mast. The metal pipe the wires run down inside, either through the roof or up the side of the house.
• The meter base and meter. The meter is generally the utility’s. The base it plugs into is generally the owner’s.

So a sagging drop between the pole and the house is a utility call. A leaning mast, a cracked weatherhead, a leaky roof boot or a rusted meter base is usually the owner’s, fixed by a licensed electrician, with the utility called in when the drop has to be disconnected. PGE, Pacific Power and Clark Public Utilities each publish their own service requirements, and the specifics can differ.

The drip loop

Drip loops were the most common overhead finding in Russ’s reports by a wide margin, turning up in Portland, Vancouver, Canby, Beaverton and Gladstone houses. Water runs along wires. Without a low point below the weatherhead, rain can follow the wires right into the cap, down the mast and into the meter base or the panel.

A good drip loop is a clear U: the wires dip below the weatherhead and then rise into it. A drop pulled tight straight into the weatherhead, or wires that enter from below the loop, leave that path open. It’s usually a small fix, but the power has to be off to do it, so it involves the utility.

The mast and its roof flashing

A mast through the roof carries the pull of the service drop all day, every day. Over years it can bend or lean. Russ found leaning masts in Lake Oswego, Oregon City and Vancouver. In Lake Oswego, the mast was braced, but the bracing cables had a lot of give. Masts that stick up well above the roof generally need bracing, and a leaning one goes to an electrician.

Height counts too. A Portland mast sat low to the roofline, which may not give the wires the clearance over the roof that current standards call for. Service wires also need clearance over driveways, walkways and decks, and from windows and doors.

The roof boot around the mast is a roof penetration like a plumbing vent. It’s often the most neglected one. Russ found mast flashing past its service life with heavy sealant smeared on (Portland), a boot covered in cracked roof cement (Lake Oswego), flashing set on top of the shingles instead of under the upper course (Beaverton), and boots missing, damaged, lifted or not lying flat (Portland, Oregon City, Vancouver). The post on roof flashing problems covers penetration flashing in general.

Wall-mounted services have their version. In a Gladstone house, the weatherhead had separated from the wall, leaving an open gap in the siding.

Trees, rubbing and abandoned services

Tree limbs and service wires don’t mix. Two Portland houses had branches around the service wires, and one had its service drop running straight through a tree. Branches rub through insulation over time and can pull the drop down in a windstorm or under snow. In another Portland house, the service drop was rubbing against a corner of the house.

Utilities generally trim around their main lines. Trimming near the service drop to an individual house is often left to the owner, and many utilities will temporarily disconnect the service so a qualified tree crew can work safely. Call the utility before anyone trims near the wires. The post on trees near the house covers what trees do to roofs, foundations and sewer lines.

Old services left behind are a smaller finding. After a service upgrade or relocation, the old mast sometimes stays. Oregon City and Portland houses had abandoned masts still on the house. Russ recommends an electrician confirm it’s dead and remove it, and the roof or siding be patched.

What the inspection covers

Russ looks at the service from the ground, from the roof when it’s safe to walk, and with the drone when it isn’t. He checks the drop for clearance and tree contact, the point of attachment, the drip loop, the weatherhead, the mast for lean and bracing, the roof boot or wall seal, and the meter base. Inside, he looks at the panel, including the grounding and bonding the post on grounding and bonding covers.

He doesn’t touch the service drop or the meter, and he can’t measure the drop’s height or tension. When something is wrong on the owner’s side, the report recommends a licensed electrician. When it’s on the utility’s side, like a sagging drop or tree limbs on the wires, the report points to the utility.

To set up an inspection, you can book online.