Can HVAC Techs Do Electrical Work in Michigan

One of the most common code violations in Michigan's mechanical trade involves HVAC contractors crossing into electrical scope without the right credentials. The line between mechanical and electrical work is clear in the code but blurry on the job site, and local inspectors enforce it strictly during rough-in and final inspections.

What Mechanical Contractors Can Wire

Michigan allows licensed mechanical contractors to run low-voltage Class 2 control circuits — wiring under 50 volts AC — without an electrical license. This covers:

• Thermostat wiring (24V AC)
• Zone control wiring
• Smart thermostat connections
• Low-voltage automation controls
• Humidistat and air quality sensor wiring

This exemption comes from NEC Article 725, which classifies Class 2 circuits as inherently limited-energy and therefore posing minimal fire or shock risk. As long as the wiring stays under 50V AC, it falls within the mechanical contractor's scope.

What Requires an Electrical License

Line-voltage work on the equipment-power side belongs to licensed electrical contractors under the Michigan Electrical Code:

• Running new branch circuits from the electrical panel to HVAC equipment
• Installing or replacing the electrical disconnect switch — the externally accessible disconnect that must be located within sight of and within six feet of the mechanical equipment
• Wiring service panels or subpanels
• Installing dedicated circuits for high-draw equipment like heat pumps or commercial rooftop units
• Any modifications to the main electrical distribution system

The disconnect switch rule trips up contractors constantly. Even on a straightforward furnace replacement where you're swapping the exact same equipment in the same location, the disconnect switch is electrical scope. A mechanical contractor who installs or moves that switch without an electrical license has crossed the trade boundary.

How Inspectors Enforce This

During a rough-in inspection, the inspector checks whether the mechanical and electrical work have separate permits from the appropriate trade contractors. If they find line-voltage electrical work on a mechanical permit with no corresponding electrical permit, they issue a code violation.

The consequences are real: the contractor of record must correct the deficiencies and pay re-inspection fees before the permit can close. Repeated cross-trade violations can lead to LARA disciplinary action and damage your standing with local building departments.

The Practical Solution

Most residential HVAC contractors handle this in one of three ways:

1. Subcontract the electrical portion to a licensed electrician. For a standard furnace or AC installation, the electrical work (disconnect, circuit run) is typically a one- to two-hour call for an electrician.

2. Coordinate scheduling with a client's electrician. On larger residential projects, the homeowner or general contractor may already have an electrician on site.

3. Hold dual credentials. Some Michigan contractors carry both a Mechanical Contractor License and an Electrical Contractor License. This eliminates the subcontracting step entirely, though it requires separate experience, examinations, and licensing through the Electrical Administrative Board.

The third option is the most efficient long-term but requires separate electrical experience, examinations, and licensing through the Electrical Administrative Board. Do not assume your mechanical hours satisfy those requirements.

The Michigan HVAC License Guide maps the exact boundaries between mechanical and electrical scope so you can plan your project workflow and subcontracting arrangements before inspection day.

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