Automatic Method and Apparatus for Adequacy of Rack Grounding With Racks
Publication Date: 2010-Jun-22
The IP.com Prior Art Database
Disclosed in a rack or cabinet power distribution unit (PDU) that puts a small, current-limited AC or DC voltage onto the rack chassis to check the grounding and bonding.
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Electrical code authorities have expressed concerns about proper grounding of IT equipment racks that are painted. Racks that are painted do not have any exposed metal surfaces. Without exposed metal surfaces, testing the grounding of the rack via an ohmmeter is not possible unless paint is scraped off.
Not only is testing a manual process,
but also removal of the paint is cosmetically undesirable and, for some metals in some environments, can lead to corrosion and rusting.
This invention is the first rack-integrated grounding integrity apparatus for non-painted or painted racks. There is no need for separate meters to measure values or instruments to remove the paint. It is a seamless method for unobtrusively verifying the grounding and bonding of racks. It can also be used to validate grounding and bonding against electrical code requirements as interpreted by electrical code authorities.
Disclosed is a rack or cabinet power distribution unit (PDU) that puts a small, current-limited AC or DC voltage onto the rack chassis to check the grounding and bonding (see Figure 1). A voltage regulator is used to put a voltage on any of the grounding conductors inside the PDU. The regulator output must be limited to less than 60 Vdc (or 42 Vp) and 240 VA to meet industry standard safety limits. A multiplexer is used to isolate the individual grounding conductors at the input (connected to the PDU chassis from the incoming line cord) and output receptacles so that separate measurements can be taken. By using a voltage regulator with a fixed output voltag...