Document control
Document control is the set of identifiers that make a drawing or a report traceable: its number, its revision, the date of that revision, the names of the persons responsible for it and the history of its earlier revisions. The design prints them in the title block of each sheet and on the first page of each report, and names each file by its document number and revision.
Read first: Drawing conventions
1Drawing and document numbers
Each sheet has a drawing number and each report or schedule a document number. A number has 4 parts: the project code, a letter for the kind, a code for the subject and a sequence number. The kind is E for an electrical drawing and C for a calculation or a schedule. The project code is an input in the Document control section of the Plant & grid page: 2 to 8 capitals or digits, SSL by default.
| Drawing number | Title |
|---|---|
| SSL-E-SLD-001 | SINGLE LINE DIAGRAM |
| SSL-E-EKD-001 | ELECTRICAL KEY DIAGRAM |
| SSL-E-LAY-001 | 220 kV SWITCHYARD PLAN AND SECTIONS |
| SSL-E-EAR-001 | EARTH MAT LAYOUT |
| SSL-E-EAR-002 | EARTH MAT TYPICAL DETAILS |
| SSL-E-DSL-001 | DIRECT STROKE LIGHTNING PROTECTION |
| SSL-E-AUX-001 | AUXILIARY SUPPLY: 415 V AC AND 220 V DC SLD |
| SSL-E-3DM-001 | 3D model |
| Document number | Title |
|---|---|
| SSL-C-EAR-001 | Earthing design calculation |
| SSL-C-SCC-001 | Short-circuit calculation |
| SSL-C-DSL-001 | Direct stroke lightning protection calculation |
| SSL-C-AUX-001 | Auxiliary supply calculation |
| SSL-C-BOM-001 | Bill of materials |
| SSL-C-CMP-001 | Compliance checklists |
The numbers above are those of a new 220 kV project. The files of the 3D model carry its drawing number. A sheet's title follows the project: the yard sheet's title carries the high-voltage (HV) level, and the auxiliary supply sheet's title carries the station-service voltages of the standards set. The notes of the single-line diagram (SLD) refer to the short-circuit calculation by its document number, so a reader can go from a sheet to the calculation behind it.
2File names
A download is named by its document number and its revision, never by the project's name: SSL-E-SLD-001-RevA.pdf for the SLD and SSL-C-EAR-001-RevA.pdf for the earthing calculation of a new project. The package of a revision, a zip file of the drawings, reports, schedules and model files, is named by the project code and the revision: SSL-RevA.zip.
The Portable Document Format (PDF) files carry the document's title, the company or project as author, and the project's name and revision as subject in their properties.
3Revisions
A revision identifies one state of the drawings and documents. The design uses two kinds:
- a lettered revision, A, B, C and on, for the working copy that is circulated for comment
- a numbered revision, 0, 1, 2 and on, for an issue
Before the first issue the working copy is Rev A. The Deliver page advances its letter, A to B and B to C, when the drawings go out for another round of comments. The inputs and drawing edits are kept, and the next files carry the new letter.
Issue, on the Deliver page, gives the working copy the next number: 0 for the first issue, then 1, 2 and on. It saves the inputs, the run, the drawing edits and the full package under that number, with the issue date. An issued revision cannot change: its files are downloaded again as they were, with the same date. The working copy then becomes the next number's first letter: Rev 1A after Rev 0, Rev 2A after Rev 1.
The files of the working copy carry the date of the day they are made. Each design run records the revision it was made under, and a download of an earlier run is stamped with that revision.
4The revision table
The revision table lists the revision being printed and the issues before it, oldest first, read down from its header. Its columns are REV, DATE, DESCRIPTION and BY. A sheet and a report show the last 3 rows. The description of a lettered revision is Issued for review, and that of a numbered revision is Issued. The BY column carries the name entered in Drawn by, on the row of the revision being printed.
A sheet carries no mark across the drawing. A lettered revision in its REV box and Issued for review in its revision table show the state of the sheet. A report of a lettered revision carries a light diagonal watermark across its pages.
Given a project issued as Rev 0 on 2 Nov 2026 and as Rev 1 on 5 Nov 2026. Its working copy is Rev 2A, and its drawings are downloaded on 8 Nov 2026.
| REV | DATE | DESCRIPTION |
|---|---|---|
| 0 | 2 Nov 2026 | Issued |
| 1 | 5 Nov 2026 | Issued |
| 2A | 8 Nov 2026 | Issued for review |
Result The sheets print Rev 2A in the REV box and the 3 rows above, with the name entered in Drawn by in the BY column of the last row. A new project prints one row: Rev A, Issued for review. Its first issue prints Rev 0, Issued, with the issue date.
5Names and dates
The Document control section takes the company's name, the project code and the names in Drawn by, Checked by and the field of the person who approves the drawings. The title block prints each name entered in its row, with the date of the revision beside it. The report's first page prints the same names in a table with the document number. The company's name heads the title block and the report's running header. Without a company, the project's name takes its place.
The project's name, client and location print in the title block. A client or location left empty prints (not given), so a missing value shows on the sheet.
6Reports and schedules
A calculation report or a schedule carries its document control on its first page. A project table gives the project, client, location, revision and date. A second table gives the document number and the names, and the revision table follows with the columns of the sheets' table. Each page carries a running header and Page n of m.
The running header names the company or the project, the document's title, its number, its revision and the date. The header of the earthing calculation of a new project reads New substation · Earthing design calculation · SSL-C-EAR-001 · Rev A · 8 Nov 2026. At its first issue it reads New substation · Earthing design calculation · SSL-C-EAR-001 · Rev 0 · 2 Nov 2026.
A report states which of the drawings it depends on were edited in Sketch mode after generation, with the number of changes. The calculation follows the inputs and the design rules, not the edits.