Circuit designation in Revit: assign loads, name them, produce the list

Circuit designation in Revit: assign loads to the nearest board, form circuits, generate designations and the circuit list.

DIN EN IEC 81346VDE 0100-510

Assign, number, tag — the same work three times

Between “the sockets are placed” and “the circuit list is ready” sit three passes that all rest on the same data and are still done separately. Every load has to be assigned to a board. Within the board the loads have to be grouped into circuits. And every circuit needs a designation that also appears on the sheet and in the list.

The effort does not grow linearly, it grows with the changes. Add a board or move a partition and the assignment shifts for a whole area — and with it the numbering and every tag that hangs off it.

The usual route

Normally the board is selected, the loads belonging to it are boxed in and a circuit is created; then the next. The order within the circuit follows the selection. That is harmless as long as nobody reads the list — the installer does, eventually, and then it shows an order that has nothing to do with the route the cable takes.

The designation is often given by hand or entered afterwards through a schedule. Both are error-prone, because neither knows the assignment — only the row you happen to be standing in.

What the module takes over

The automation assigns every load to the nearest board and forms geographically sensible circuits per board. It uses a nearest-neighbour chain from the board: the circuit grows along the shortest paths, not along the selection order. The maximum number of loads per circuit is given; once it is reached, the next circuit starts.

A consistent designation following the pattern UV01-F01.1 is written to the parameter GTech_Stromkreis — board, circuit, running number. The scheme is free: the placeholders {UV}, {F}, {F2} and {i} can be assembled into whatever designation your office uses, and a preview shows the first few as you type. Everything is then tagged.

The circuit list reads those designations back, groups by board and circuit and orders the loads by running number. Each run shows from → to with room, cable type and length; the length is derived from the straight-line distance with an allowance. The list is therefore an evaluation of the model and not a second version maintained in parallel.

The module's smaller commands go with it: add a circuit afterwards, assign a switching group, tag everything, and refresh the tags after a change.

Why the order within a circuit matters

A circuit list is not read on screen, it is read on site. Whoever works through it goes from load to load. If the list is in the order somebody clicked months ago, the fitter jumps around the storey ticking off rows twenty metres apart.

The nearest-neighbour chain changes the decisive part: the circuit starts at the board and grows to the nearest load each time. What comes out is not a mathematically shortest route — that would be a different and considerably harder problem — but an order that matches the way the cable is actually run and that can be worked through without thinking.

For estimating it has the same effect. The length in the list — straight line plus allowance — is only a usable approximation if the order roughly matches the installation. With a random order you are summing routes nobody would ever lay.

What should be settled beforehand

Two decisions belong before the first run. The first is the designation scheme. Whether the board is called UV01 or V1.01, whether the circuit is written with one digit or two, whether a dot or a hyphen separates circuit and running number — that is office standard or a client requirement. Setting it once costs two minutes; changing it afterwards means regenerating every tag.

The second is the maximum number of loads per circuit. It follows from the design, not from the tool. It is the value that determines how many circuits end up existing, and therefore how large the board becomes.

After that the sequence is always the same: assign loads and form circuits, write the designation, tag, produce the list. If something changes, the same chain runs again. The command that refreshes the tags makes sure nothing stays on the sheet that no longer holds in the model.

Standards

Named for this tool are DIN EN IEC 81346 and DIN VDE 0100-510. The first governs the system of reference designation — the structure of something like UV01-F01.1 — the second the identification of equipment in electrical installations.

Because offices and clients differ in notation, the scheme in the tool is freely configurable rather than hard-wired. Which notation applies on a project is decided by the client's requirements or the office standard — the tool applies it consistently instead of setting it.

Consistency is the essential part. A designation is only worth as much as it is built the same way across the whole project; a list carrying three notations because three people worked on it costs more time later than it saved during entry. That is exactly what machine assignment takes off you: it has no off days.

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