How do inspection findings become asset health and circuit health?

An inspection produces findings: observations about one component, on one date, supported by an image and a named reviewer. Asset condition, circuit health and repair priority are separate records built from those findings, each under its own rule. A useful system keeps four things visible at every step: the most severe current finding, the components nobody observed, the consequence data that came from other systems, and the trail back to the photograph.

ThreeV builds for that whole cycle, from the inspection itself to the prioritization and capital planning that follow it. This article sets out the method: the four records, the rule each one follows, and the fields a utility should keep so that a replacement decision can be explained later.

What is the difference between a finding and an asset's condition?

A finding records what an inspector, or a model checked by an inspector, saw on one component. A usable finding names the structure and the component, the date of the images, the images themselves, the condition observed, the defect priority assigned to it and the person who reviewed it. A broken insulator with several flashed sheds is a finding. So is a split crossarm, a loose guy wire or a woodpecker hole.

Defect priority belongs to the finding. Codes such as P1, P2 and P3 say how soon one defect needs a response, and they are set by people with the authority to make that call.

Asset condition is a separate record: a summary of one structure, built from all of its current findings. It needs its own scale. ThreeV has seen asset-level tiers labeled with the same P1 to P5 notation that crews use for individual defects, and the result reads as though a pole with only minor findings were a scheduled P4 repair. A high, medium and low condition tier avoids the collision.

The link between a finding and its image needs the same care. Field forms often record findings in one place and photographs in another. When a crew fills in a questionnaire on site and attaches several photographs to the structure as a whole, a later reviewer cannot tell which image supports which finding. ThreeV's inspection records attach the evidence images to each answer, so that link exists before any roll-up begins.

How does an asset's condition come from its findings?

Two rules carry most of the weight.

The most severe current finding sets a floor. Averaging a severe insulator defect with a dozen components in good condition produces a structure that looks acceptable. CNAIM, the Common Network Asset Indices Methodology that Great Britain's distribution network operators use for regulatory reporting, handles this with a collar: an observed condition can set "a minimum limit" on an asset's health score, so one serious finding holds the score down however many other inputs look healthy. ThreeV's condition records keep the finding that set the floor attached to the asset, so anyone reading the condition can open that defect and its image directly.

The record lists what was not observed. A structure with no findings may be in good condition, or its crossarm may not appear in any usable image. Those are different facts. Each component should be marked as observed, not observed or not applicable, with the date and the images behind every observation.

How should missing inspection data count?

Every roll-up has to decide what to do with a component that has no current evidence. CNAIM answers the question directly: where an operator lacks the data for a condition input, "the default values for that Condition Input" are applied. The rule keeps a calculation complete across an entire asset base. It also lets two poles land in the same health band when one was inspected last month and the other has a single overview photograph from three years ago.

A utility can keep the calculation and still preserve the difference. The asset record carries a coverage field beside the score, listing which components were observed, on what date and in which images. A circuit report then shows two numbers side by side: the condition of assets with current evidence, and the count of assets without it.

ThreeV has seen what happens without that field. In a September 2026 review of a condition dashboard built on one utility's existing inspection records, poles with no current inspection record appeared as failing an inspection-date control, and repair controls showed as blank because no work-order data was supplied. Each display was accurate to the data supplied, and neither showed whether a given pole was in good condition. ThreeV's approach is to report unknown condition as its own state at every level, with the date of the last usable evidence, so a planner can see where the next inspection crew should go.

How should asset condition roll up to circuit health?

A circuit summary faces the same problem at a larger scale. An average across every structure on a feeder can report fair condition while two adjacent poles are in poor condition, and adjacency matters because one crew visit, or one outage, can involve both.

A circuit health record should report three things together: how the condition tiers are distributed, which assets are worst and where they sit, and how many assets have no current evidence. ThreeV's prototype circuit roll-up starts from the average of its assets and adds a penalty based on the weakest tenth of structures, so that a small cluster of weak structures cannot disappear inside a healthy mean. The weights are exposed as assumptions for each utility's engineers to review and set.

Where does repair priority come from?

An inspector can record that a crossarm is split. The inspector usually cannot see how many customers the circuit serves, whether the structure sits in a high fire-threat district, or whether a hospital is downstream. Those facts live in GIS, outage and customer systems. Field inspectors reviewing a draft inspection form in September 2026 made the same point about wildfire zones: that attribute belongs to the circuit record, and the form should not ask the inspector to judge it.

CNAIM separates these inputs by design. Its Health Index relates to an asset's condition and probability of failure, a Criticality Index relates to the consequence of failure, and a Risk Index combines the two. A US utility can adopt the separation without adopting the methodology. With condition and consequence in separate fields, an engineer can ask whether a structure ranks high because it is in poor condition, because its failure would be costly, or for both reasons. ThreeV's methodology keeps them separate for the same reason and treats the weights that combine them as configuration. Prioritization frameworks differ between utilities, and the weights belong to the engineers who answer for the decisions.

The next step is the unit of work. Under the Federal Energy Regulatory Commission's Uniform System of Accounts, electric plant consists of retirement units and minor items of property, and each utility keeps a written property units listing. When a minor item is replaced independently of the retirement unit it belongs to, the cost is charged to maintenance, unless the replacement is a substantial betterment. A list of individually ranked insulators can therefore describe the right repairs and still need regrouping by structure or line segment before it matches how the work will be funded. The treatment of any specific component depends on the utility's own listing. ThreeV's approach carries structure and line-segment identifiers from the asset record into the prioritized list, so repairs can be grouped into the work packages a utility funds and schedules.

The record is complete when the work is. A work order, a completion date and an after-photograph close the finding and become evidence for the next inspection. Work orders often live in a separate system from inspection records. In that case the condition record should state that closure evidence is missing, so an open defect never reads as a repaired one.

What this method does not establish

A health score built from findings and weights orders assets by condition. It becomes a probability of failure only after it is calibrated against outcomes observed over years, which is how CNAIM relates its Health Index bands to failure rates. The weights in any prioritization framework are judgments about what matters most to one utility, and they should be recorded and versioned alongside the scores they produce. The accounting treatment of a repair follows the utility's own property units listing.

A minimum record checklist

Where ThreeV fits

ThreeV works across the whole cycle, from the inspection itself through prioritization and capital planning. Vision, ThreeV's managed inspection offering, records reviewed findings with their evidence images attached. Validate is being built for the steps that follow: holding asset condition and coverage, rolling them up to circuits, and keeping the trail from a prioritized repair back to the photograph. Scoring stays configurable, because each utility's engineers set their own priorities.

The checklist above is a practical starting point for any inspection program, with or without ThreeV. Questions about applying it to an existing program can go to the ThreeV team.