Server Rack Planning and Selection
Which cabinet fits your room, your equipment and the rules
Server rack planning starts with three questions: what goes in, where it stands and how it will grow. The answers decide height, width and depth, the door type, the load capacity and the accessories, from a compact wall-mount cabinet to a full data center row.
Data centers need deep racks with perforated doors for airflow. Small offices often manage with a wall-mount cabinet. Shared sites use colocation racks with separate locked compartments, and special rooms or machines need a custom-built cabinet. Planning also covers accessories, workstations and the rules on energy efficiency that apply from 2026.
Lehmann IT has planned and built server cabinets in Salach, Germany, since 1983, from standard sizes to one-off builds. The questions below help you choose and plan.
Questions on choosing and planning
What makes the RZ Pro a data center rack? →Cabinets for data centersWhy perforated doors on a server rack? →Airflow through the RZ-PROHow does a colocation rack separate tenants? →Separate lockable compartmentsWhen does a wall-mounted cabinet make sense? →Compact IT on the wallWhen is a custom server rack the right choice? →Built to your requirementsWhich accessories does a cabinet need? →Shelves, PDUs, cable managementWhat is a LAN rack control desk? →IT workstation in the rackIs your server room ready for 2026? →Energy Efficiency Act checklistWhy does Lehmann IT build in Germany? →Own production in Salach
Find the products in the Lehmann IT shop
Ready to choose? These shop categories show the matching products with prices and configuration options.
Server cabinets →Wall-mount cabinets →Colocation racks →Custom special cabinets →Planning and consulting →Advisor: everything you need to know about server cabinets
The most common questions about server cabinets and network cabinets, answered briefly by Lehmann IT.
What is a server cabinet?
A cabinet, usually made of sheet steel, that protects IT hardware from overheating, external influences and theft, and with it your data from unauthorized access.
What do 19 inch and U mean?
19 inch (482.6 mm) is the standard mounting width. 1 U (rack unit) = 44.45 mm. A 12 U cabinet holds up to 12 devices of one rack unit each.
What to look for when buying?
Height, width and depth. 42 and 48 U are common; smaller cabinets come with 12 to 34 U. Common widths: 600, 800 and 1000 mm. We are also happy to build to measure.
Which location?
Plan before you install. In dusty environments, choose a cabinet rated IP54/IP55; in the office, a soundproof server cabinet.
Which server cabinet suits you?
Choose your location, one click takes you straight to the right series.
Office and home officeCompact and quiet, 12 to 25 UOffice server cabinet →Workshop, lab, equipment roomEasy to access, well ventilated, cost-effectiveOpen rack →Company and server roomSturdy and flexibleIT Plus server cabinet →High demands25, 42 or 48 UHigh End server cabinet →Data centerHigh rack density, perforated doorsRZ Pro server cabinet →Network and telephonyFor communication equipment with low heat loadNetwork cabinet →
Server cabinet or network cabinet?
Server cabinets mainly hold servers, network cabinets mostly communication equipment with a low heat load, often with closed doors front and back.
Open or closed?
Open racks are easy to access, well ventilated and affordable. Closed cabinets protect better against dust, moisture and theft, and they are quieter.
Cable management and castors
Cable guide brackets, patch panels and cable ducts keep things tidy. Almost every model is available with castors, levelling feet and reversible doors, see accessories.
Perforated doors
In the data center, cool air flows in through perforated doors and waste heat flows out, with full protection for the hardware. Typical of RZ Pro server cabinets.
Colocation Racks
42 or 48 U, divided into 2, 3, 4 or 6 separate compartments, each with its own lock, for shared server rooms: colocation racks.
Built to measure
Special sizes, colours or equipment are built in Salach, Germany: custom special cabinets and planning support.
All server cabinets: Office · Open racks · IT Plus · High End · RZ Pro · Network cabinets · Stainless steel
Checklist for server rack planning
- List the equipment: every device with its height units, depth, weight and power draw, plus a reserve for growth.
- Measure the site: room size, door widths, floor load and whether the cabinet stands on the floor or hangs on the wall.
- Decide on doors and airflow: perforated doors for data centers, glass or solid doors for offices, sealed housings for harsh sites.
- Plan cables and accessories: cable entries, cable management, shelves, PDUs, blanking panels and monitoring.
- Check the rules: energy efficiency requirements from 2026, fire protection and access control for the site.
Frequently asked questions
Which size of server rack do I need?
Add up the height units of all devices, then add a reserve of about a third for growth and airflow. The depth must suit the deepest device plus space for cables and power. Width depends on the cabling: wider cabinets leave more room for cable management.
Floor-standing or wall-mount cabinet?
Wall-mount cabinets suit small installations such as a switch, a patch panel and a small server in an office. As soon as more equipment, heavier devices or more depth are needed, a floor-standing server cabinet is the better choice.
What is a colocation rack?
A colocation rack divides one cabinet into several separately lockable compartments. Different customers or departments share the rack, but each one only has access to their own compartment. This is common in data centers and shared technical rooms.
When does a custom-built cabinet make sense?
A custom cabinet makes sense when standard sizes do not fit: unusual room dimensions, special equipment, integration into machines or vehicles, or particular requirements for protection, colour or access. Lehmann IT builds such cabinets in its own production.
What do the 2026 energy efficiency rules mean for server rooms?
The rules aim at more efficient data centers and server rooms. Good airflow, the right cooling and measurable power use help meet them. Planning the cabinet with efficiency in mind from the start is easier than retrofitting later.
How much load can a server rack carry?
Load capacity depends on the frame, the profiles and the base. Data center racks carry heavy servers and storage systems, while wall-mount cabinets are made for lighter equipment. The product pages state the permitted load for each model.
Can Lehmann IT help with the planning?
Yes. Lehmann IT plans server cabinets, server rooms and data center rows, from the first sketch to the finished installation, and builds the cabinets in its own production in Salach.
Planning with Lehmann IT
Lehmann IT has designed and built server cabinets in its own production in Salach, Germany, since 1983. Because development and manufacturing sit under one roof, standard cabinets can be adapted and special versions built when a project needs them. This knowledge site explains the technology in depth, so you can understand the options before you decide. When you know what you need, the Lehmann IT shop at lehmann-it.de shows the matching products with prices and configuration options, and the team in Salach helps with questions on choosing and planning by phone or email.