Shielding Cabinet Configuration Specifications

Cabinet body: Fully enclosed cabinet welded from 1.5 mm cold-rolled steel sheets, treated with galvanization and powder coating for corrosion protection;
Shielded door (single front door): Door assembly welded from high-quality shielding mesh and cold-rolled steel sheets;
Equipment mounting rails: Adjustable in front–rear and top–bottom directions, supplied with 50 sets of cage nuts and screws;
Server shelves: 1 shelf for cabinets under 1.6 m; 3 shelves for cabinets 1.6 m and above;
Ventilation waveguide windows (2 sets): Honeycomb type, one set at the top and one at the bottom, 300 × 300 mm each;
Castors / leveling feet: Robust and durable, allowing multi-directional and multi-angle smooth movement;
Axial cooling fans:MTBF > 18,000 hours, single fan airflow 1.4 m³/min × 4 units;
Power line filter: Featuring high insertion loss and excellent suppression bandwidth; AC 220 V × 16 A, 1 set included;
PDU:16 A, 8-way Chinese standard (Type I) sockets, 1 unit;
Network cable waveguide tubes: Ø8.1 × 100 mm copper waveguide tubes, (Shielded Cat.6 network cables supplied in pairs), 10 tubes included;
Fiber optic waveguide tubes: Ø14 × 140 mm, 5 tubes included;
Grounding:1 grounding copper braid;
Compliance:Performance meets BMB 19-2006 Class C requirements.

Main Applications of Shielded Cabinets

To prevent leakage of sensitive information generated by computers, network servers, and communication electronic equipment during operation;
To protect the above equipment from external electromagnetic interference (EMI) during operation, ensuring stable and reliable performance;
Widely used in industries and institutions with high confidentiality requirements, such as government agencies, national defense, banking, securities, military, education, and scientific research.

Principle of Electromagnetic Shielding

Electromagnetic shielding is a measure that uses shielding enclosures to prevent the propagation of high-frequency electromagnetic fields in space.
When electromagnetic waves pass through metal materials or shielding layers that attenuate electromagnetic energy, the waves experience a certain degree of attenuation. These metal materials or shielding layers therefore provide a shielding effect.
The shielding effectiveness depends on the properties of the electromagnetic waves as well as the intrinsic characteristics of the metal or shielding material.

Physical Process of Electromagnetic Shielding by Metal Plates

When electromagnetic waves are incident on a metal plate with air on both sides, part of the energy is reflected, resulting in reflection loss;
The portion of the transmitted wave that is attenuated during propagation within the metal plate is referred to as absorption loss;
When the wave reaches the second interface, it is reflected back to the first interface, causing repeated reflections.
This process continues until the energy is completely attenuated or transmitted.
This phenomenon corresponds to the multiple-reflection correction factor considered in electromagnetic shielding theory.

Shielding of Seams

Permanent seams on shielding enclosures generally refer to seams formed by welding two metal plates together.
Such permanent seams exhibit radio-frequency (RF) impedance nearly equal to that of the metal plates themselves.

Filters

Conducted interference refers to interference transmitted through metal conductors, such as cables or any metallic structures.
All conductive penetrations entering a shielded room or cabinet must be filtered.
A filter is a device used to eliminate interference signals. It is a circuit that effectively attenuates frequencies other than a specified frequency (or frequency band).
Its function is either to pass a desired frequency or to suppress a specific undesired frequency.

Precautions

The shielded cabinet must be reliably grounded.
Residual current devices (RCDs / earth leakage circuit breakers) must not be installed upstream of the power line filter.
The RCD may be installed inside the shielded enclosure’s distribution box, or an isolation transformer may be installed between the RCD and the input of the power line filter to prevent nuisance tripping caused by leakage current. Alternatively, fuses and air circuit breakers without leakage protection may be installed upstream of the power line filter.

Order Code	Capacity	Width	Depth	Height	Internal Dimensions	Fully-assembled Volume	Weight
PB-7714	14	700	700	1000	19"x550x620
PB-7014	14	700	1000	1000	19"x870x620
PB-7720	20	700	700	1250	19"x550x900
PB-7020	20	700	1000	1250	19"x870x900
PB-7726	26	700	700	1550	19"x550x1200
PB-7026	26	700	1000	1550	19"x870x1200
PB-7733	33	700	700	1850	19"x550x1500
PB-7033	33	700	1000	1850	19"x870x1500
PB-7737	37	700	700	2000	19"x550x1650
PB-7037	37	700	1000	2000	19"x870x1650
PB-7742	42	700	700	2200	19"x550x1850
PB-7042	42	700	1000	2200	19"x870x1850