What is the ZW1 file format?
A .zw1 file is a project backup archive created by EPLAN Electric P8, a professional electrical engineering CAD application used for designing schematics, panel layouts, and documentation. Despite its custom extension, a .zw1 file is structurally a 7-Zip archive renamed with an EPLAN-specific suffix - the standard 6-byte 37 7A BC AF 27 1C 7-Zip magic bytes are present at offset 0.
Inside the archive, EPLAN packages the complete project directory structure: .fdb Firebird database files (schematic data), .sdb symbol databases, .xdb cross-reference databases, and .eod project options files. EPLAN restores a project by extracting these components into a working project folder via Project → Backup/Restore.
The .zw1 extension denotes a standard project backup. Related extensions share the same 7-Zip container for different data categories: .zw2 for symbol libraries and .zw3-.zw5 for other EPLAN data types.
Because the underlying format is 7-Zip, the archive contents can be inspected with 7-Zip directly, though the individual .fdb Firebird database files inside require EPLAN or a Firebird-compatible client to interpret. Backup files are not backward-compatible: a .zw1 created in a newer EPLAN version cannot be restored in an older one. EPLAN Electric P8 has been rebranded as simply "EPLAN Electric" in versions from 2023 onward.
Security & safety
RISK: LOWZW1 files contain engineering project data (schematics, configurations). They are not executable. No known malware vector. If received unexpectedly, confirm the sender - industrial espionage risk for sensitive designs, but no inherent system risk.
Format details
in a nutshellPrograms that open ZW1 files
Windows2 apps
EPLAN Electric P8
Paid Project menu → Restore (or Backup → Restore) → Browse to the .zw1 file → Restore. 
7-Zip (inspect only)
Open-source Right-click the .zw1 file → Open archive with 7-Zip to view/extract contents. Cannot process EPLAN project data without EPLAN software. Technical details
deep spec| Underlying container | Standard 7-Zip archive (`.7z` format) with `.zw1` extension rename |
| Magic bytes | `37 7A BC AF 27 1C` (7-Zip signature) at offset 0 |
| Compression | LZMA / LZMA2 (7-Zip default algorithms) |
| Archive integrity | CRC-32 checksum per file entry within the 7-Zip container |
| Contained file types | `.fdb` (Firebird schematic DB), `.sdb` (symbol DB), `.xdb` (cross-reference DB), `.eod` (project options) |
| Extension taxonomy | `.zw1` = project backup; `.zw2` = symbol library; `.zw3`-`.zw5` = other EPLAN data types |
| Version compatibility | Forward-compatible only; newer versions restore older files, not vice versa |
| Platform | Windows only (EPLAN Electric does not run on macOS or Linux) |
| Encryption | None by default |
| Byte order | Little-endian (7-Zip format specification) |
| Typical size | 1 MB - several GB depending on project complexity and embedded graphics |
| Restore workflow | Project → Backup/Restore → Restore Project in EPLAN Electric |
| Released | EPLAN Electric P8, circa 2006 |
| Latest version | Compatible with EPLAN Electric P8 version used to create it and later (no internal version field) |
| Specification | www.eplan.help |
ZW1 conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about ZW1 files.
