Revit MEP Electrical: What an AutoCAD Engineer Needs to Know

The short answer

In AutoCAD you draw a drawing. In Revit you build a model that carries data, and every drawing is a view of that model, generated rather than drawn. For electrical work that means three things: a socket is an object with a voltage, a load and a number of poles rather than a block; a panel schedule is produced from the circuits you assign rather than typed into a table; and a cable tray is real geometry that can be clashed against HVAC ducting. Change the model and every plan, section and schedule showing it changes with it.

The concepts that matter

Families and types. A family is the object definition, a twin socket, a recessed luminaire, a distribution board, and a type is a variant of it. What makes a family electrical is the electrical connector inside it, carrying the load classification, the apparent load in VA, the voltage and the number of poles. Without a connector the object can be placed, tagged and counted, but never circuited, so it will never reach a panel schedule.

Levels. Everything is hosted on a level. A socket at 300 mm is placed on a level with an offset, and the level is what a floor plan view cuts through. Get levels wrong at the start and every view is wrong.

Worksets. Worksharing splits one central model so several people work at once in local copies, borrowing elements as they edit and synchronising back. Worksets also let you unload the HVAC model while working on lighting, which is the difference between a model that opens in twenty seconds and one that opens in five minutes.

Electrical Settings. Under Manage, MEP Settings, Electrical Settings you define voltage definitions and distribution systems. Default templates ship with North American values, so an Indian project needs a 240 V definition, a 415 V definition and a three-phase four-wire 415/240 V system at 50 Hz. Until that exists, panels have nothing to be set to and circuits will not connect.

Circuits. Select the devices, create a power circuit, assign it to a panel; Revit then knows the connected load, the poles occupied and the circuit number. The load classification on each family decides which column of the schedule it lands in, and the demand factors configured per classification turn connected load into estimated demand.

Worked example: what the panel schedule totals

A three-phase 415/240 V board with 12 lighting circuits at 1,150 VA each and 9 socket circuits at 2,000 VA each:

• Lighting: 12 x 1,150 = 13,800 VA
• Power: 9 x 2,000 = 18,000 VA
• Connected total: 31,800 VA

Line current at 415 V three-phase is the total VA divided by (1.732 x 415) = 31,800 / 718.8 = 44.2 A.

Apply a demand factor of 1.0 to lighting and 0.8 to the sockets and estimated demand becomes 13,800 + 14,400 = 28,200 VA, or 39.2 A. Both figures appear on the schedule, and the gap between them comes entirely from the demand factors you set.

Notice what Revit did not do: it did not balance phases beyond the order you assigned circuits in, did not check volt drop, did not size the cable and did not select the protective device. It added up VA and divided.

Cable tray, conduit and why clients ask for BIM

Tray and conduit are modelled as real objects with widths, fittings and elevations. That is slower than drawing a double line, and it is the whole commercial argument: once the tray exists in three dimensions the services model can be clashed against structure and HVAC, usually in Navisworks, and every clash resolved in the office is a hole not cut on site.

Model the tray at true width and model the space it needs, not only the metal, cables need bending radius and pulling access. Clash detection only sees geometry that exists, so a tray drawn as a line clashes with nothing.

What an LOD specification commits you to

Read this before pricing. A tender asking for LOD 350 services is asking for supports and penetrations, several times the work of LOD 300, and consultants lose money on that clause more often than any other.

Honest limitations

Revit models and documents; it does not analyse. No load flow, no short-circuit calculation, no discrimination study, no earth fault loop impedance, no arc flash. A Revit load schedule is an addition of apparent loads with demand factors applied, it is not a load flow study, and presenting it as one is how people get caught.

Cable sizing and protection coordination still belong to a calculation against IEC 60364 or IS 732 in a separate tool, and lighting levels to a lighting calculation package. Revit's job is to hold the results as data and draw them consistently.

What goes wrong

Modelling in 2D inside a 3D tool. Detail lines look right on a sheet and carry no data: nothing schedules, nothing clashes, nothing coordinates, and you have paid Revit prices for an AutoCAD deliverable. If it is equipment, place a family.

Families downloaded from the internet with no electrical parameters. They look correct and place happily, then the panel schedule comes out empty because there is no connector, no load classification and no VA figure. Check one family's connector before placing three hundred.

Worksets ignored. Either worksharing was never enabled and people pass the .rvt around a shared drive, where the last save wins and a day's work vanishes, or everything lands in Workset1, so nothing can be unloaded and the team queues for element ownership. Set worksets up at project start; retrofitting them is miserable.

Circuiting left to the end, so every schedule, phase balance and load total appears in the last week, when there is no time to fix what they reveal.

What to learn next

Get the project template right first, voltage definitions, distribution systems, load classifications and panel schedule templates, set up once for the voltages you actually work at. Then learn one coordination workflow end to end: link the architectural model, model tray, export to Navisworks, run a clash test, resolve. Schematic work stays in a different tool, and that split is covered in EPLAN vs AutoCAD Electrical vs SOLIDWORKS Electrical.

Frequently asked questions

Does Revit replace AutoCAD Electrical? No. Revit models building services in three dimensions; AutoCAD Electrical draws panel and machine schematics with cross-referencing. Most consultancies need both.

Can I import my AutoCAD drawings? Link them as an underlay to trace from, then delete the link. Leaving CAD files inside a Revit model bloats it and imports their line styles permanently.

How long until I am useful in Revit? For an engineer who already knows the electrical design, a few weeks. The modelling is not the hard part; project setup and coordination discipline are.