Commercial job guide
Rooftop HVAC electrical connections in Calgary
A rooftop HVAC replacement needs an electrical scope tied to the exact new unit and the mechanical contractor’s schedule. Confirm power, controls and commissioning responsibilities before the crane booking. A replacement unit should not be assumed to match the existing electrical connection.
CCT 01What the first visit needs to establish
Ask the mechanical supplier for the approved unit submittal and options, including heaters, economizers, drives and controls. The electrician needs the final configuration rather than a catalogue page for the product family. Identify the existing unit and whether its operation has been troublesome.
The site review should cover the available electrical supply and route, roof access, local equipment condition and which controls are being reused. Do not send office staff onto a roof or into electrical equipment to collect details. Existing service records and externally visible labels can help the contractors prepare.
CCT 02What to include in the work order
Assign the power connection, disconnect equipment, control wiring, building-automation programming and manufacturer start-up separately. Include temporary disconnection and the handoff that allows the mechanical contractor to remove the old unit. Roof penetrations and waterproofing need a named owner as well.
Where equipment interfaces with a fire alarm or smoke-control arrangement, the appropriate designer and specialists must define the work. Treat that interface as an identified scope item; it should not be improvised when the replacement unit is already on the roof.
CCT 03What changes the price and schedule
A changed electrical requirement, deteriorated rooftop equipment or an inaccessible cable path can add work. Compare quotations against the same final submittal and state whether the existing feed is assumed reusable pending assessment. A lower allowance for electrical work is not meaningful if it excludes all adaptation.
Schedule dependencies can cost more than a small material change. Agree the readiness check before the lift, the cancellation decision, attendance windows and the restart sequence. The City permit guidance helps the team confirm the electrical approval path alongside mechanical permits.
CCT 04Information to send with your request
- Existing and new unit models, approved electrical submittals and selected options.
- Mechanical contractor and controls vendor contacts.
- Roof access arrangements, landlord rules and known site restrictions.
- Crane or delivery date, with a separate readiness-check date.
- Which tenant areas lose heating, cooling or ventilation during the work.
- Fire alarm or building-automation interfaces already identified by the design team.
CCT 05What a completed job should leave you with
Ask for confirmation of the electrical connection, controls handoff and completed start-up responsibilities. Retain final settings and equipment documents with the mechanical records so the next service team is not starting from a generic drawing.
Have the operator check the intended occupied and unoccupied functions with the responsible contractor. Record outstanding seasonal checks separately if the current weather cannot demonstrate every operating mode. A unit that runs briefly during handover has not necessarily proved all of the building's required controls.
Questions people ask
Does the HVAC contractor include the electrical connection?
Should the electrician attend the crane lift?
Sources and further reading
Use the official links in this guide and the editorial standards. Scope and procurement checklists are editorial planning guidance, not quotations or installation instructions.