KEY ELEMENTS OF CABINET/RACK SELECTION
A cabinet has four rails for mounting equipment, a door (or doors) & sides. Cabinets are often fully welded structures
A rack is a free standing 2 or 4 post frame, no doors or sides. A rack may have independent equipment mounting rails or have mounting provisions integrated into the frame elements. A rack may be welded or bolted together.
The decision to use one versus the other depends on many factors.
LOCATION & ENVIRONMENT:
A secured & robustly climate controlled environment, & specific applications may allow for an open design of racks.
Protecting equipment from dusty or industrial environments would fit more appropriately with the use of cabinets & may require one with a NEMA (National Electrical Manufacturers’ Association) or IP (International Electrotechnical Commission) rating. NEMA or IP ratings are designed to address corrosion resistance due to splashed liquids or uncontrolled environments, dust, falling objects & other hazards, exterior exposure or submersion. NEBS-Telcordia standards exist for protection against seismic activity, shock or vibration.
Organization of assets & aesthetics can also lead to choosing a cabinet over a rack.
Careful consideration should be paid to Thermal Management in all situations to insure that mission critical equipment operates at optimal performance levels.
H&H supplies axial fans, impellers, blowers, air conditioners, heat exchangers, & heaters depending upon the environment & expected thermal load. Fans, impellers & blowers are most common for indoor, climate controlled spaces, including offices, labs, data centers & some warehouse applications. Air conditioners, heat exchangers & heaters are more appropriate for exterior or heavy industrial applications, or non-climate controlled environments.
There are a number of methodologies when it comes to Thermal Management. Hot Aisle/Cold Aisle topology, In-row cooling, thermal insulation, & direct ducting are all viable options. The calculation of total thermal load, ambient temperature, & permissible temperature rise are important factors to consider when determining the size & type thermal management to be deployed.
H&H Industrial Corp cabinets, racks & accessories adhere to the EIA 310-E Standard, defined by the Electronic Industries Alliance
WIDTH – Nominal Horizontal Panel Opening (HPO – usable space) for racks & cabinets is 19”, while hole center to hole center of equipment mounting rails measures 18.31”. This dimension is defined by the Electronics Industries Alliance in their standard, EIA 310-E. H&H also provides cabinets, racks & accessories with nominal 23”, 24” & 28” HPOs. Actual equipment chassis clearance in 19” rack or cabinet is 17.75”.
HEIGHT – The Vertical Panel Opening (VPO – usable space) of a rack or cabinet is designated by Rack Units. One Rack Unit equals 1.75”H. This is also defined by EIA 310-E. Standard cabinet or rack heights are 26U, 36U, 40U, 42U, 44U, & 48U. Other heights based upon the Rack Unit designation are available. H&H equipment mounting rails are stamped with Rack Unit numbering & indexing marks.
DEPTH – cabinets & four post racks are available in depths ranging from 24” to 48” to accommodate various sized equipment & requisite cabling. H&H Industrial Corp’s equipment mounting rails are infinitely adjustable over the full usable depth of any cabinet or four post rack.
When specifying Width, Height & Depth of a cabinet or rack, consider equipment & cabling functionality & clarify whether inside or outside dimensions are stated.
WEIGHT/ EQUIPMENT LOAD:
Cabinets & racks vary in level of weight capacity. H&H standard Benchmark cabinets have a 2000lb static load maximum weight capacity. Cabinets with greater maximum capacity or meeting dynamic load requirements are available. What type & how much equipment is required to achieve your purpose? Calculate the combined weight of proposed equipment before specifying a rack or cabinet. Heavier loads may necessitate the use of a more stable cabinet over an open rack. Conversely, easy, frequent access to all sides of your equipment may lead to a rack being specified.
EQUIPMENT MOUNTING RAILS:
The vertical equipment mounting rails used in cabinets or racks are comprised of a series of three holes (spacing: 5/8-5/8-1/2”) in each Rack Unit, as defined by EIA 310-E. These holes may be tapped, Universal Square or round through holes. H&H standard tapped are 10-32. Tapped rails are also available as 12-24 or M6 upon request. Universal Square hole are second most commonly used. WECO spaced equipment rails are also available. H&H equipment mounting rails are stamped with Rack Unit numbering & indexing marks.
There are many options available for providing power to rack mounted equipment. Power strips with amperage from 10A – 30A, Single Phase 110-220 & Three Phase 208/380/400/480 Voltages can be mounted either vertically or horizontally. NEMA 5-15, 5-20 receptacles & 5-15, 5-20, 5-30plugs, IEC 320 C13 & C19 receptacles, & Cord Sets with Standard, Locking or Hardwired connections are also available. Power Distribution Units (PDUs) & Power Managers can provide additional capabilities, including remote management, & current monitoring & metering. Uninterruptible Power Supplies (UPSs) provide redundant power to Mission Critical resources.’
The routing & management of interior cabling is an important consideration when specifying a cabinet or rack. Cable & bundle size, direction of run, top or bottom feed & Inter-rack connections all influence management & routing options. H&H has a wide variety of methods to most efficiently meet your needs.
From shelving to cable drapes, fans/impellers to grounding & isolation options, H&H has a full array of accessories to match any scenario, including
- Blank Panels – Conventional, Tool-less & Hinged
- Shelving – 4Pt stationary, 2Pt cantilever or pullout, from 30-500lbs capacity
- Storage drawers, w/ & w/o covers
- Grounding – Ground Studs: 10-32, ¼-20, up to 3/8-16; Ground straps #16GA -4GA; copper Bus Bars, Tapped, w/studs & isolated
- Casters from 200-1000lbs max capacity/ea
- Levelers, Anti-tip legs & Dolly Bases