Grounding IT enclosures
- Thread starter vavelar
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bphgravity
Senior Member
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- Florida
Re: Grounding IT enclosures
Article 645.15 requires "all exposed non-current carrying metal parts of an information technology system shall be grounded in accordance with Article 250 or shall be double insulated."
Would this qualify?
Article 645.15 requires "all exposed non-current carrying metal parts of an information technology system shall be grounded in accordance with Article 250 or shall be double insulated."
Would this qualify?
- Location
- Illinois
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- retired electrician
Re: Grounding IT enclosures
Article 645 only applies within an "information technology equipment room". It is not an "information technology equipment room" unless all of the conditions in 654.2 are met. I know that there are installation standards that require grounding for this type of equipment, but I'm not sure that there is an NEC requirement that applies.
Don
Article 645 only applies within an "information technology equipment room". It is not an "information technology equipment room" unless all of the conditions in 654.2 are met. I know that there are installation standards that require grounding for this type of equipment, but I'm not sure that there is an NEC requirement that applies.
Don
Re: Grounding IT enclosures
Victor the short answer is yes. If the cabinets have any type of electrical circuits such as power or signal in or around them, you are required to ground the cabinets. It doesn't matter if they qualify for 645 or not. If the racks/cabinets have AC installed in them and the EGC is bonded by some means then you have met the minimum requirements of the NEC.
If the racks are supplied by 48 volt DC power then a DC frame ground will be needed. The DC frame ground is similar to an EGC, except it is not run with battery conductors, and is larger than required by NEC 250.122.
However neither of these two grounds will meet the requirements of equipment manufactures signal ground requirements. This type of ground is typically constructed via # 4 AWG grid under the raised floor system, then each cabinet/rack is bonded to the grid in addition to any EGC supplied via AC power. This is an engineering design question not an NEC issue.
[ June 05, 2003, 11:45 AM: Message edited by: dereckbc ]
Victor the short answer is yes. If the cabinets have any type of electrical circuits such as power or signal in or around them, you are required to ground the cabinets. It doesn't matter if they qualify for 645 or not. If the racks/cabinets have AC installed in them and the EGC is bonded by some means then you have met the minimum requirements of the NEC.
If the racks are supplied by 48 volt DC power then a DC frame ground will be needed. The DC frame ground is similar to an EGC, except it is not run with battery conductors, and is larger than required by NEC 250.122.
However neither of these two grounds will meet the requirements of equipment manufactures signal ground requirements. This type of ground is typically constructed via # 4 AWG grid under the raised floor system, then each cabinet/rack is bonded to the grid in addition to any EGC supplied via AC power. This is an engineering design question not an NEC issue.
[ June 05, 2003, 11:45 AM: Message edited by: dereckbc ]
Re: Grounding IT enclosures
Dereck,
I'm not sure I understand 100% what you mean in the last sentence. And I'm not sure you understood what the real question was... i.e., If I have an equipment rack in which I mount one or more listed, corded devices (essentially "appliances"), and each device has an equipment ground conductor in its cord, and all device grounds eventually connect back to a common ground point upstream at the separately derived source, is it necessary to ground the rack if the rack itself is not an electrical device? In other words, the rack is not intended, nor is it "likely" to become energized.
Thanks
Vic
Dereck,
I'm not sure I understand 100% what you mean in the last sentence. And I'm not sure you understood what the real question was... i.e., If I have an equipment rack in which I mount one or more listed, corded devices (essentially "appliances"), and each device has an equipment ground conductor in its cord, and all device grounds eventually connect back to a common ground point upstream at the separately derived source, is it necessary to ground the rack if the rack itself is not an electrical device? In other words, the rack is not intended, nor is it "likely" to become energized.
Thanks
Vic
Re: Grounding IT enclosures
Vic I understand. If you have an metallic equipment rack with plug and cord equipment installed like a server, router, mux, ect, and metalic communication cables, IMHO it is likely to become energized. Therefore it should be grounded by some means. Now if your plug and cord equipment (with EGC) effectively grounds the rack by bolting it in, then I believe you have satisfied the NEC requirement for safety.
If this is just a single rack or two installed in a closet, that is all you really need to do. However, if this rack is in a data center, more should be done, and that is a design issue...
Vic I understand. If you have an metallic equipment rack with plug and cord equipment installed like a server, router, mux, ect, and metalic communication cables, IMHO it is likely to become energized. Therefore it should be grounded by some means. Now if your plug and cord equipment (with EGC) effectively grounds the rack by bolting it in, then I believe you have satisfied the NEC requirement for safety.
If this is just a single rack or two installed in a closet, that is all you really need to do. However, if this rack is in a data center, more should be done, and that is a design issue...
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