opciones de cantos y tiradores / edgebanding and handles colors

3.7.1

3.7.1.1 The requirements for a grounding system apply to raised floor areas containing network elements such as power, switching and transport equipment.

3.7.1.2 Additional evaluation may be required if any of the following are not part of the overall design:

(a) All equipment in the raised floor area is served by primary dc distribution circuits protected by over-current devices rated or set at no more than 600 amperes.

(b) All cable racks between the raised floor area and other parts of the MSC are metallic, and the stringers for each cable rack have a combined cross-sectional area of .582 square inches minimum.

(c) All raised floor support structure components and cable rack sections are interconnected by a permanent means such as welding, or a mechanical means, such as approved junctioning hardware that provides electrical continuity between all components.

(d) Cable racks are elevated from the floor a sufficient distance to allow all grounding conductors to be run and secured using conventional methods and to permit the grounding conductors to pass under cable rack intersections.

3.7.2

3.7.2.1 The CO GRD bus bar should be mounted in a central location and should be connected to the OPGP with a 750 kcmil vertical equalizer conductor. The CO GRD bus bar should be mounted at least 12" above the raised floor Note: In single story buildings, even though most of it is run horizontally, the conductor between the OPGP and a CO GRD bus bar is also called a vertical equalizer.

3.7.2.2 Originating at the floor CO GRD bus bar, a horizontal equalizer conductor shall be installed under the raised floor area and shall be sized as follows:

(a) If all power plants serving equipment in the raised floor area have their battery return bus bars (also called discharge ground bars) connected to the CO GRD system on the same floor or within one floor of the raised floor area, the horizontal equalizer conductor shall be #1/0 AWG minimum.

(b) If any power plant serving equipment in the raised floor area has its battery return bus connected to the CO GRD system more than one floor from the raised floor area, the horizontal equalizer shall be 750 kcmil minimum.

Note: If the Ground Window and its ground window bar (GWB) are located in the raised floor area, it may be convenient to use the conductor (or a portion of it) between the CO GRD bus bar and the GWB as the horizontal equalizer.

3.7.2.3 The horizontal equalizer shall be placed along one side of a main aisle cable rack serving the common bonding network equipment area. The preferred location is the side that provides the shortest bonds to BDFBs.

3.7.2.4 If more than one main aisle exists, the horizontal equalizer shall be branched to serve other main aisles.

Note: Branches serving other main aisles may originate at a point on the initial horizontal

equalizer, or directly at the CO GRD bus bar, whichever provides the shortest route between the CO GRD bus bar and the equipment served.

3.7.3

3.7.3.1 All conductors, connectors, frames, cabinets, and other metallic objects that are part of an isolated bonding network shall be insulated from contact with common bonding network objects. Unless special arrangements are provided, objects in a raised floor area that are always considered part of the integrated ground plane include:

(a) Raised floor pedestals, stringers, and tiles (all surfaces) (b) Cable rack sections

(c) All suspended ceiling components, including support structure, light fixtures, and air ducts (d) All metallic conduits and raceways serving common bonding network equipment

3.7.3.2 Isolated bonding network equipment shall be grounded per equipment system requirements and/or the requirements in Section 4 of this Standard.

3.7.4

3.7.4.1 Lineups that contain common bonding network (integrated ground) equipment shall be equipped with a minimum #6 AWG stranded copper conductor routed along the side of the lineup cable rack that faces the front of the equipment lineup. This conductor shall originate at the horizontal equalizer or a conductor extended from it, or from a CO GRD bus bar.

3.7.4.2 All common bonding network equipment frames, cabinets and other enclosures shall be equipped with a minimum #6 AWG conductor connected between the lineup conductor and a point at either the top or the bottom of the frame or cabinet. See Figure 3-4

3.7.4.3 On frames, cabinets or other enclosures using a stranded bay ground lead (SBGL), the #6 AWG DCEG conductors should be C-tapped to a point on the lower portion of the SBGL's bare #6 AWG conductor. The top end of the SBGL conductor should terminate at the framework ground point at the top of the frame, cabinet or other enclosure. See Figure 3-4

3.7.5

3.7.5.1 Cable rack sections are considered adequately bonded when mechanically joined to the raised floor support system and approved junctioning hardware is used on both stringers at cable rack splices and both stringers of an intersecting rack.

3.7.5.2 When any section of cable rack is not joined together and to the raised floor support structure, it shall be bonded by one or a combination of the following:

(a) A bond at each end of the cable rack section to the adjoining section of cable rack using a minimum #1/0 AWG conductor

(b) A bond at each end of the cable rack section to the nearest point on the raised floor support system or CO GRD conductor using a minimum #1/0 AWG conductor

3.7.5.3 When an arrangement consisting of more than one cable rack section is not mechanically joined to the raised floor support system, the cable rack sections shall be bonded together and the entire arrangement shall be bonded to the raised floor support system using a minimum of four #1/0 AWG bonds. The four bonds shall be equally spaced throughout an approximate 20' x 20' area. When a cable rack arrangement covers an area greater than 20' x 20', additional bonds shall be provided. Typical cable rack bonding is shown below.

Figure 3-4

Figure 3-5

Typical Bonding Required When Cable Rack is Not Secured to the Raised Floor Support Structure