EOM plans — as-built electrical model
EOM stands for electrical equipment and lighting: plans for sockets, lighting, power equipment, cable routes, grounding and other sections. Each plan is built from the building through rooms to electrical points, groups, routes and the panel — it is a single electrical model, not a set of symbols: one outlet is at the same time a plan object, part of a group, a load, an element of a cable circuit, a calculation, a diagram and a specification.
Plan types
15 plan types are available. Each plan includes its own set of layers by default (architecture, legend and title block are added automatically). If no type is set, a combined plan is used.
| Plan | What it shows |
|---|---|
| Socket network plan | Sockets, posts, attachment to walls and groups |
| Normal lighting plan | Luminaires and controls (switches), groups |
| Emergency lighting plan | Emergency and escape luminaires, exit signs |
| Escape lighting plan | EXIT signs, direction indicators, exit zones |
| Outdoor lighting plan | Outdoor luminaires, floodlights |
| Power equipment plan | Cookers, boilers, air conditioners, motors |
| Equipment power supply plan | The “panel → device → cable → equipment” link |
| Cable route plan | Trays, trunking, corrugated conduit, pipes |
| Low-current systems plan | Structured cabling, video surveillance, access control |
| Grounding plan | PE, main earthing terminal, equipotential bonding, connection points |
| Equipotential bonding plan | Main earthing terminal, PE, metalwork |
| Lightning protection plan | Air terminals, down conductors, earth electrodes |
| Electric heating plan | Underfloor heating, heating cables, thermostats |
| Electrical equipment plan | Combined electrical points and equipment |
| Combined EOM plan | Architecture + sockets + lighting + equipment + routes |
Layers
Only one layer can be active for inserting objects. Electrical layers are marked separately; architecture, annotations, dimensions, legend and title block are service layers.
| Layer | Purpose |
|---|---|
| ARCHITECTURE | Architecture (underlay) |
| LIGHTING | Lighting |
| EMERGENCY_LIGHTING | Emergency lighting |
| SOCKETS | Socket network |
| POWER | Power equipment |
| EQUIPMENT | Equipment |
| CABLE_ROUTES | Cable routes |
| GROUNDING | Grounding |
| LIGHTNING_PROTECTION | Lightning protection |
| LOW_CURRENT | Low-current systems |
| ANNOTATIONS | Annotations |
| DIMENSIONS | Dimensions |
| LEGEND | Legend |
| TITLE_BLOCK | Title block |
Electrical points
A point is a parametric object with a complete engineering model: designation (P1, O1, S1, QF1), room and floor, mounting height (for example h=0.300), IP rating, group, panel, protective device, RCD (current and type AC/A/B), phase, cable (type, cross-section, length) and power in watts.
| Category | Examples |
|---|---|
| socket | Sockets |
| switch | Switches |
| light | Luminaires |
| emergency_light | Emergency and escape luminaires |
| power_load | Power loads: cooker, boiler, air conditioner |
| junction_box | Junction boxes |
| panel | Panels |
| cable_route | Routes and trays |
The allowed categories depend on the layer: LIGHTING accepts luminaires and switches, SOCKETS — sockets, POWER — power loads and boxes, CABLE_ROUTES — routes and boxes. All categories except the cable route can be electrically connected (a route has no group, panel or cable like a load does).
Groups and connection topology
Points with the same groupId form a group (for example, all kitchen sockets — P1). Each connection is described by the chain “from → to → with which cable → in which circuit → from which panel and device → phase, neutral, PE”. The connection length is recalculated from the route geometry.
- The group designation is taken from the first point (for example P1) or assigned by category: P — sockets, L — luminaires, S — switches, EL — emergency lighting, PWR — power, “Gr.” — other.
- A group stores the panel, protective device, RCD and cable — they are inherited from the points of the group.
- Points without a groupId are automatically collected into temporary groups by category, so that the check highlights them as unconnected.
Cable lengths: how they are calculated
The length is calculated only along the real orthogonal geometry (Manhattan: the sum of |dx| + |dy| + |dz| over the route points), not along a straight line. The total line length is the horizontal runs plus the vertical drop (the absolute difference between the laying height and the mounting height of the load), multiplied by a margin. The default margin is 10% (factor 1.1), and the result is rounded up to 0.1 m.
- Input: route points in millimetres, the mounting height of the load, the laying height, the margin factor.
- Calculating the length along a straight line (hypotenuse) is not allowed — only the orthogonal path plus the vertical plus the margin.
- The resulting length goes into the connection model, the cable schedule and the specification.
Group phase balancing
For a three-phase supply, single-phase groups are distributed across L1/L2/L3 by a greedy algorithm: fixed phases are taken into account first, then large unassigned groups are assigned to the least loaded phase. The result is an assignment for each group, the total power per phase and the maximum imbalance as a percentage of the average load (to 0.1%). A fixed phase is never changed by the algorithm.
Legend and symbols
The legend is built only from the symbols actually used on the sheet: each unique category and type yields one entry with a count. Unused symbols do not appear in the legend. The symbol library is parametric: each type has an electrical meaning (number of poles, presence of an earth contact, default IP rating, for example IP20 for indoor sockets and IP44/IP65 for damp and outdoor ones).
Model checks: step by step
- Place the points by room — place sockets, luminaires, switches and power loads, and specify the mounting height and IP rating.
- Bind them into groups — give each point a group (groupId), panel, protective device and cable. Check the phase of single-phase groups.
- Build the connections — for each line set “from → to”, the circuit and the panel. The length is recalculated from the route geometry.
- Run the integrity check: points without a group, duplicate group designations, groups without a panel and device, and broken connections (FROM/TO referencing nothing) are listed as remarks.
- Fix the remarks and repeat the check, then issue the legend, cable schedule and specification (see “Documents and export”).
Common errors
- Point without a group (POINT_WITHOUT_GROUP) — set a groupId; otherwise the point falls into a temporary group and will not be included in the circuit correctly.
- Duplicate group designation (DUPLICATE_DESIGNATION) — rename one of the groups, designations must be unique.
- Group without a panel and device (GROUP_WITHOUT_PROTECTION) — specify a panelId or breakerId, otherwise the group cannot be protected or included in the diagram.
- Broken connection (BROKEN_CONNECTION) — FROM or TO references a non-existent point, group or panel; check the identifiers.
- Entering a “straight-line” length manually — do not underestimate the length: the program calculates the orthogonal path plus the vertical plus the margin, rounded up.
Limitations
- Length is calculated along the orthogonal route: diagonals and arbitrary curves are approximated by polylines of horizontal and vertical segments.
- Phase balancing distributes only single-phase groups across the three phases; three-phase loads and fixed phases are not reassigned.
- The legend reflects only the symbols in use — for the full catalogue of symbols, see the equipment library.
See also
- Cable schedule
- Specification
- Single-line diagram
- Cabinets and assembly
- Floor plan
- Documents and export
Frequently asked questions
How does an EOM plan differ from an ordinary drawing?
An EOM plan is a model: each point knows its group, panel, device, cable and phase. Changes immediately propagate to the groups, lengths, diagram, schedule and specification.
Why is the cable length longer than the straight-line distance?
Because the cable runs orthogonally (along the walls), plus vertical drops and rises, plus a 10% margin rounded up to 0.1 m. This is what the method requires; a straight line is not allowed.
How do I balance the load across phases?
Run phase balancing: fix the phases that must not change, and the rest are distributed automatically — large ones to the least loaded phase. Check the resulting imbalance in percent.
The legend has few entries — is that an error?
No: the legend shows only the symbols actually used. If the sheet has 7 types, the legend will have 7 entries with counts.