How Drawing Review Caught a Wiring Miss on Seattle Apartments
- The spec called for three current-carrying conductors on one circuit type and the legend showed two. A fuse on the same set was sized at 20A for a continuous load that needs at least 25A.
- Helonic, AI drawing review software, read the electrical spec, the legend, and the schedules against each other.
- The firm said a similar heat-pump wiring change had already become a change order of about $80,000. Its director of architecture compared the review to a senior electrical engineer with 20+ years of experience.
Seattle, WA. Missing conductor and undersized fuse.
Lead Finding
3 conductors in spec, 2 in legend
Second Finding
20A fuse, 25A+ needed
Similar Change Order
~$80K on heat-pump wiring
A Conductor Count That Did Not Match and a Fuse Too Small
An architecture firm was designing a Seattle apartment building with heat-pump heating. The electrical set included a specification, a legend, and equipment schedules.
Heat-pump wiring repeats across a building, so a mistake in it repeats too. The firm had already seen a similar heat-pump wiring change turn into a change order of about $80,000.
The firm wanted the electrical set checked before the same kind of error reached the field.
Helonic Read the Spec, the Legend, and the Schedules Together
The firm uploaded the PDF set and Helonic read the electrical specification, the legend, and the schedules together.
The finding that mattered most was a mismatch in conductor count. The spec called for three current-carrying conductors on one circuit type, and the legend showed two. One of the two is wrong. If the legend is what the electrician builds from, the circuit gets pulled with a conductor too few.
The firm's director of architecture said this kind of miss usually needs a full review by an electrical engineer. It sits between two documents that each read as reasonable alone, and the only way to see it is to hold them side by side.
The second finding was on the same set. A fuse was sized at 20A for a continuous load that needs at least 25A. He said that one would otherwise have shown up at commissioning, when fixing it means changing equipment and re-testing.
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The Kind of Miss That Usually Takes a Senior Electrical Engineer
Both items went to the electrical engineer of record with the sheets and the values marked. The conductor count was reconciled between the spec and the legend, and the fuse was resized for the continuous load.
The director of architecture pointed to the earlier heat-pump wiring change, which had already become a change order of about $80,000, as the reason this mattered.
His comparison was to a professional senior electrical engineer with 20+ years of experience. In his experience, nobody finds this type of issue.
“This is the quality of a senior electrical engineer with 20-plus years of experience. In my experience nobody finds this type of issue. A similar heat-pump wiring change had already turned into an $80,000 change order.”
Frequently asked questions
What was the main finding on the Seattle apartment building?
The spec called for three current-carrying conductors on one circuit type, and the legend showed two.
What was the second finding?
A fuse on the same set was sized at 20A for a continuous load that needs at least 25A. The firm said it would otherwise have shown up at commissioning.
Why does a conductor count mismatch matter?
If the circuit is built from the legend, it is pulled with one conductor too few. The firm said a similar heat-pump wiring change had already become a change order of about $80,000.
How did the firm describe the review?
The director of architecture compared it to the quality of a professional senior electrical engineer with 20+ years of experience, and said nobody finds this type of issue in his experience.
Does Helonic replace an electrical engineer's review?
No. The director of architecture said this kind of miss usually needs a full electrical-engineer review. Helonic reads the spec, legend, and schedules together and flags the mismatch for the engineer to resolve.
Manas Gandhi
Co-founder & CTO, HelonicManas is the co-founder and CTO of Helonic, where he leads engineering and AI research for construction drawing analysis. He works directly with structural, MEP, civil, and fire protection engineers to translate the way they review drawings into AI systems that flag the issues that actually matter in the field. Before Helonic, he built machine learning pipelines for technical document understanding and has spent the last several years interviewing licensed design engineers and discipline leads to ground product decisions in real practice rather than industry assumptions.
- AI for technical document understanding
- Cross-discipline coordination workflows
- Code compliance automation (IBC, NEC, NFPA, IPC, IMC, ASCE)
- Structural and MEP drawing review systems
How this page was researched: Reviewed against Helonic's 2026 drawing-analysis categories, RFI workflow, and product capabilities.
Last reviewed by Manas Gandhi · October 4, 2026