Reference

The electrical estimating glossary

Every term on this page opens with a one-sentence definition you can quote. Each entry is anchor-linkable — pages across this site link here the first time a term appears.

TAKEOFF

Takeoff

The counted list of every material and device a set of drawings requires, with quantities. Everything downstream — labour hours, material cost, the bid — is arithmetic applied to the takeoff, which is why a missed count is the most expensive mistake in estimating. VOLTA's AI drafts the takeoff from your PDF drawings; you review and adjust every quantity.

ASSEMBLY

Assembly

A pre-bundled group of items priced as one unit — a "suite package" might bundle the receptacles, switches, smoke detector wiring and panel connections of a typical apartment. Assemblies make multi-residential bids fast: count suites, not devices. VOLTA ships multi-res assemblies (in-suite, corridor-per-floor, main service, feeders, EV rough-in) calibrated for Canadian multi-family work.

LABOUR UNIT / LABOUR FACTOR

Labour unit & labour factor (NECA labour units)

A labour unit is the standard time to install one item under normal conditions; a labour factor scales that time for reality. The trade standard reference is the NECA Manual of Labor Units, which pairs units with condition columns. In practice: effective hours = base hours × structure factor × conditions factor. VOLTA applies NECA-style factors automatically — wood frame ×1.00 up to occupied building ×1.75, plus working-condition adjustments — and shows the factor on every line so nothing is hidden. A priced labour-unit chart (item · unit hours · factor · extended hours · dollars) is generated for every estimate in the calculation report.

MARKUP VS. MARGIN

Markup vs. margin

Markup is a percentage added to cost; margin is profit as a percentage of the selling price — and they are not the same number. A 20% markup produces a 16.7% margin. Bids priced by markup but judged by margin quietly underperform, which is why VOLTA's cockpit shows the live margin next to the bid total as you slide the markup.

OVERHEAD

Overhead

The cost of running the shop that no single job pays for directly — office, insurance, vehicles, estimating time itself. It's typically recovered as a percentage on every bid; forget it and every "profitable" job subsidizes the business into a loss. In VOLTA, overhead is an explicit slider applied to the totals waterfall.

PANEL SCHEDULE

Panel schedule

The table on the drawings (and in the finished installation) listing each circuit in a panel — breaker size, load, description. For estimators it's dense, high-value information: circuit counts drive device and wire quantities. VOLTA reads panel designations from the drawing text and uses them in its draft — more on the panel schedule feature page.

OST

On-screen takeoff (OST)

Doing the takeoff from a digital drawing on screen — clicking devices, tracing runs — instead of paper and highlighter. VOLTA's variant starts one step ahead: the AI drafts the count from the PDF text first, and your on-screen work is review and correction, not counting from zero.

TENDER PACKAGE

Tender package

The document set a bid is priced from: drawings, specifications, addenda, bid forms and closing date. In Canada "tender" is the common word for what US contractors call the bid package or RFP documents.

RFP

RFP (request for proposal)

An invitation to submit a priced proposal, usually weighing more than price alone — approach, schedule, qualifications. Distinct from a fixed tender where the low compliant bid generally wins.

CONTINGENCY

Contingency

A percentage added to cover what the drawings don't show yet — addenda, site surprises, price movement between bid and build. Too little is risk; too much loses the job. VOLTA carries contingency as its own visible line in the totals waterfall, not buried in the markup.

Quick answers

What is a labour unit in electrical estimating?

A labour unit is the standard time to install one item under normal conditions — for example, hours per receptacle or per metre of conduit. Estimators multiply the unit by the quantity, then adjust with factors for structure type and working conditions. The NECA Manual of Labor Units is the trade's standard reference.

What does an electrical labour-unit pricing chart look like?

Three columns: the item, its labour unit (hours each), and the extended hours (unit × quantity). Priced charts add a labour rate column so each line shows dollars. VOLTA builds this chart automatically for every estimate and shows the factor applied to each line — you can inspect the whole thing in the calculation report.

What's the difference between markup and margin?

Markup is added to cost (20% markup on $100 cost = $120 price). Margin is profit as a share of price ($20 profit on $120 = 16.7% margin). Quoting a "20% markup" and expecting a 20% margin is one of the classic ways bids quietly lose money.

What is a takeoff in construction estimating?

The takeoff is the counted list of everything the drawings require — devices, fixtures, wire, panels, with quantities. It's the foundation of the estimate: prices and labour hours are applied to takeoff quantities.

What is on-screen takeoff (OST)?

Counting and measuring from a digital drawing on screen instead of paper — clicking devices, tracing wire runs. VOLTA goes one step further: its AI drafts the count from the PDF first, and you review on screen rather than counting from zero.

See every term in action. VOLTA shows units, factors, markup and margin live on a real bid.

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Keep reading: how to estimate electrical work in Canada · the blog · for freelance estimators