Commercial electrical permit drawings: what to expect

Why commercial work needs drawings

For a house, an electrical permit can often be issued with a short description of the work. Commercial and industrial jobs are different. The permit authority usually needs drawings that show what will be installed, where, and how it is fed, so a Safety Codes Officer can review the design and later inspect against it.

What is required depends on the authority, the size and use of the building, and the scope of work. A small tenant improvement in a strip mall needs far less than a new warehouse with a large service. The City of Edmonton and other authorities publish submission requirements for commercial permits, and they are the final word.

What a drawing set usually includes

• Cover sheet and legend. Symbols, general notes, applicable code edition and the scope of work.
• Power plan. Receptacles, dedicated equipment connections, data and floor boxes, and circuit numbers on the floor plan.
• Lighting plan. Fixtures, switching and controls, emergency lighting and exit signs. Energy code requirements for lighting may also apply to the project.
• Single-line diagram. How power flows from the service through switchgear, transformers and panels to major loads.
• Panel schedules. Every circuit, its breaker and what it feeds, with connected and demand load totals.
• Load calculation. Proof the service and feeders can carry the new and existing load.
• Details. Mounting, grounding and bonding details, equipment specifications and interfaces with fire alarm or mechanical systems.

Panel schedules and load calculations

Plan reviewers spend a lot of time on panel schedules and loads, because that is where overloaded services and mismatched circuits show up. A clear schedule also becomes a working document for facility staff long after the job is done.

For tenant improvements, the existing panel is often the constraint. A site survey before design confirms what is really there, whether the landlord's records are accurate and how much spare capacity exists. See load calculations.

Who prepares and seals the drawings

Depending on the building and scope, drawings may need to be prepared and sealed by a professional engineer registered with APEGA. Larger buildings, assembly and care occupancies, large services and complex systems commonly fall into that category. Smaller, simpler jobs may be accepted from a qualified electrical contractor.

Whether a seal is required is set by the authority and the applicable codes, not by preference. If you are not sure, ask early. We cover this in more detail in working with electrical engineers.

Either way, the person who signs the drawings takes professional responsibility for the design. That is one reason reviewers expect drawings to be complete and internally consistent, not a sketch with notes.

Landlords often add their own requirements too: approved contractors, drawing review by their engineer, shutdown windows and specific equipment. Get the tenant handbook early.

Industrial and larger projects

Industrial work adds layers. Motor control centres, variable frequency drives, process equipment and hazardous locations each bring their own code sections and drawing content, such as area classification drawings, motor schedules and control wiring diagrams.

Larger projects are often permitted and inspected in stages: underground and grounding, rough-in by area, service energization, then final. Your drawings and schedule should anticipate those stages so inspections line up with construction.

It also helps to separate permit drawings from construction drawings in your thinking. The permit set must show enough for review. The construction set adds the detail crews need on site. On smaller jobs they are often the same set; on larger ones they diverge.

Keeping plan review on track

1. Confirm the scope with the landlord or owner, including what is base building and what is tenant work.
2. Survey the existing service, panels and fire alarm before design starts.
3. Coordinate with architectural and mechanical drawings so equipment and ceiling layouts match.
4. Submit a complete package. Missing schedules or load calculations are a common cause of review comments.
5. Respond to review comments promptly, and revise every affected sheet, not just one.
6. Keep site changes documented so as-built drawings match what was installed.

Alberta Electrical prepares permit drawings and electrical design and layout for tenant improvements and other commercial work, and works with your engineer where a seal is required. Our online reporting tracks drawings, permits and inspections in one place.

Common questions