1. What's U of Rack Cabinet?
U is Rack Unit Calculator, it is a very useful tool for any installer who needs to know exactly what equipment to buy when building a 19" Rack. 1U=1.75 inches=44.45mm 1U included 3 holes



2. About 19" installation
There could be different width installation, 19", 21", 23", etc, but 19" is the most common and standard installation. For 19" cabinets, the distance of mounting rails is 19 inches (482.6 mm), including edges or ears that protrude on each side which allow the accessories installed. The installation holes distance between two mounting rails is 465mm. The most important dimension is the internal rack width.
3. About welded structure cabinets
Welded structure cabinets are usually with better loading capacity and stability because of the welded frames. Labor cost on the assembling will be saved, but delivery costs and storage costs should be taken in consideration when choosing a welded structure cabinet. For welded structure cabinets, the key points are the welding skill, product materials and surface finishing.
4. About bolted structure cabinets
Bolted structure cabinets could be shipped in assembled packing and disassembled packing. When cabinets are delivered in disassembled packing, a lot of shipping space and storage space will be saved, but you will need labors to assemble them up.
For bolted structure cabinets, the key point is that they could be assembled quickly and adjusted flexibly. Good 19" standard cabinets are not only stable with or without full loading, compatible with different safety norms, but also with good sealing for the doors and side panels, meet various applications requirements.
5. About wall mount enclosures
For wall mount enclosures, it is possible to place them on floor to use them as free standing cabinets or mount them on the wall. Keep in mind that while wall mount cabinets conserve floor space, they have weight restrictions that should be considered when making a decision about the type of rack to be used.
6. About Rack frames, Doors and Side Panels
Rack frames can be open 4-post frames.
Doors and side panels should be completely removable for easy installation of equipments. Some side panels are bolted from outside for easy removal, others are bolted from inside for higher security.
7. About rack sizes
The most important dimension is the internal rack width. EIA standard 19 inch racks are common in IT, while 23 and 24 inch racks are used by telecommunications service providers.
The external width is also important. Wider cabinets obviously take up more floor space. They also provide more internal space for cabling. KVMs (Keyboard, Video, Mouse aggregators) and PDUs (Power Distribution Units) can be mounted at the side of the rack if there is enough space. This takes up zero rack space (0U height).
There is no single internal depth standard, even for 19 inch racks. It can be 600mm, 800mm, 900mm, 1000mm, 1100mm or even 1200mm.
Rack and server heights are measured in "U" units. Popular cabinets heights are 12U/24U/42U and 47U extra-tall.
8. How to choose the right size cabinets
When you choose server cabinets or network cabinets, you need take in consideration of the loading capacity, ventilation, stability, sizes, cable managements, power distribution and cooling capacity, etc.
There are 2 major factors: the type of equipments needed for rack mount capabilities and the amount of equipments requiring rack space. Users should always keep the extra space based on the total amount of rack units currently needed because of the future expansion. If additional rack mounted accessories such as battery back-up, remote power management is required, extra front and rear cabinet space might be needed.
9. About surface finishing
To avoid rusty, raw materials SPCC should be treated carefully, the surface finishing usually includes the procedures: Degreasing pickling, phosphoric, power coated.

(Degreasing—Water washing—Pickling—Water washing—Neutralization washing— Water washing—Surface conditioning—Phosphoric—Water washing—Dry—Automatic powder coating—Manual powder coating—Drying)

10. About frames, doors and side panes of 19" racks

Rack frames can be open 4-post frames.
Doors and side panels should be completely removable for easy installation of equipments. Some side panels are bolted from outside for easy removal, others are bolted from inside for higher security.

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