An electrical bid rarely goes wrong on the panel schedule. Panels, feeders, branch wiring and devices carry a quantity and a unit rate, and every estimator prices them the same careful way. Money leaks at the edges: systems that are electrical work everywhere except on this particular tender, and boundary clauses that assign a duty to whichever trade reads them first, or to neither, if nobody does.
Four things are electrical scope on essentially every tender, worth naming only so the edges below stand out by contrast. Power distribution, complete: service, switchgear, panels, feeders, branch wiring, devices, priced straight off the one-line diagram and the panel schedules, which are the real price list here — everything else below is what the one-line doesn't show. Lighting and controls: fixtures per the schedule, lighting controls, emergency and exit systems, where fixture count and control complexity (occupancy sensing, daylight harvesting, a lighting control panel with its own programming) move the bid more than the fixture spec itself. Equipment connections: power to mechanical and owner-supplied equipment per the equipment schedules, each with its own voltage, breaker size and disconnect requirement. And grounding, raceways and supports: the complete raceway system, cable tray, grounding and bonding, the unglamorous majority of the labour hours and the easiest place to under-count.
Where the money leaks
Start with the Division 23/26 boundary, because it repeats more than any other item on this list. Every mechanical unit on the schedule needs a starter, a VFD or a disconnect, furnished by one trade and wired by another, and specs assign the split inconsistently, sometimes unit by unit within the same schedule. The same ambiguity extends to duct detectors, damper actuators and fan interlock wiring: electrical in one spec, mechanical controls in the next. There's no default answer, only what this tender's schedule says, checked against every unit on it, not the first three.
Fire alarm carries the same problem in a different shape. It's frequently a licensed specialty sub-scope sitting under the electrical umbrella rather than electrical work itself, and even when it is electrical, panel programming is routinely carved out as a separate duty from device installation and wiring. Add verification (the ULC/NFPA-style commissioning step that proves the system works) and there are four distinct obligations — device install, wiring, programming, verification — that a tender can assign to as few as two parties or as many as four. The gap that costs money is programming and verification excluded from every bid at once, because each bidder assumed someone else had it.
Low-voltage work sits in its own grey zone: communications, security and AV systems under Divisions 27 and 28 go to the electrical contractor as often as they go direct to the owner on a separate contract entirely. Both are common, so the tender has to say which this one is. If it doesn't say clearly, that silence is the finding to flag before pricing, not after. Temporary power is a milder version of the same thing: formally a Division 01 general-requirements duty, it lands on electrical by default often enough that "by others" needs confirming rather than assuming. The real cost isn't the initial hookup: it's who pays for consumption across a schedule that might run a full winter, and who relocates temporary distribution as the site sequence moves.
Two items sit just outside the boundary and are worth confirming rather than assuming. Control wiring furnished under mechanical (BMS and control wiring frequently stated as Division 23 or 25 work, explicitly excluded from electrical) matters less for the exclusion itself than for confirming the tender states it outright. And utility company work (utility-side service, transformers, their fees) follows the utility's own rules, not the spec's; what you price is the demarcation point and any charges assigned to the contractor on the customer side of it.
A handful more never show up where you'd look for them, which is exactly why they get missed. General notes sometimes prohibit aluminum conductors above a certain size, or mandate spare capacity in feeder sizing, and both change conductor tonnage and read like boilerplate until they don't. An arc flash study or a Cx (commissioning) participation requirement can sit in a single line of a general note and represent real engineering hours the fixture count never suggested. Kitchen equipment, medical equipment, IT racks and process equipment all need power, and their connection counts live in equipment schedules outside Division 26, a separate document you have to go find. Fire alarm programming and verification is worth repeating here too, since it's the single most commonly double-excluded item on this list. So is the Division 23/26 boundary, because it doesn't happen once. It happens once per mechanical unit on the schedule.
A name on the other side of every boundary
Every edge above has a name on the other side of it, and the coordination that avoids a dispute happens at bid time, not at rough-in:
| Trade | What to reconcile before you price |
|---|---|
| Mechanical | Every scheduled unit's electrical characteristics against the electrical drawings: flag mismatches now, and wire to whichever document governs. |
| Fire alarm specialty | Device install vs. wiring vs. programming vs. verification: confirm which of the four is yours. |
| General contractor | Temporary power's extent, who pays energy costs, and the timing of switchover to permanent power. |
| Utility | Demarcation point, metering, fees, and any schedule dependency on utility-side work outside your control. |
| Drywall | In-wall rough-in and device box placement need to be confirmed and inspected before walls close, a sequencing conversation, not just a scope one. |
None of this needs reading the spec like a novel. It needs reading the mechanical equipment schedule with the same attention as the panel schedule, checking every starter/VFD/disconnect assignment individually rather than assuming the first one sets the pattern, and treating "fire alarm" as four separate line items until the tender proves otherwise. The edges above are what turn a complete-looking Division 26 read into a bid that's complete. They're exactly the kind of requirement that gets buried on page 40 of a document nobody has time to read twice.