kwpatriot
Electrical
- Feb 16, 2016
- 1
Hello there, I have a question about a raised floor and it needing to be grounded or not.
My only past experience with grounding a floor has been in data centers, where there is 120/208/480v above and below a raised floor that is 3-4 feet tall. In one case, the engineer designed a cross-over grid system where every other raised floor pedestal was grounded, and each grounding clamp was quite expensive. So that is sort of one extreme.
Anyways, now we are faced with a 'low profile' raised floor that is only approximately 2 inches tall. The raised floor panels are made out of plastic and the floor has metal trench covers. The basic layout is there is a 2 foot x 2 foot grid of cable/wire trenches, and the electrical and data cabling is placed into the trench, the metal trench covers are put on top, then you put the floor carpet or tile on top of that.
This particular installation is a standard office building, so each user will have a 1-2 computers, a phone, personal power strip, etc. No medium voltage equipment, but likely some small desktop UPS systems.
There have been some recent discussions (for this project) that code might require the raised floor and/or the metal cable trench covers to be grounded. The problem we are having is the inspector does not have experience with this type of raised floor (honestly do not know if he has any experience with any type of raised floor) and is taking a very conservative interpretation of the code.
Can anyone recommend what to do? The floor manufacturer tells us that 99.9% of their customers do not require grounding but did say it is ultimately up to the local code and inspector. The project engineer apparently did not consider there to need to be grounding because it wasn't shown on any drawings and is deferring to the inspector.
Thank you very much for your help!
PS- This is for a project located in the U.S.
My only past experience with grounding a floor has been in data centers, where there is 120/208/480v above and below a raised floor that is 3-4 feet tall. In one case, the engineer designed a cross-over grid system where every other raised floor pedestal was grounded, and each grounding clamp was quite expensive. So that is sort of one extreme.
Anyways, now we are faced with a 'low profile' raised floor that is only approximately 2 inches tall. The raised floor panels are made out of plastic and the floor has metal trench covers. The basic layout is there is a 2 foot x 2 foot grid of cable/wire trenches, and the electrical and data cabling is placed into the trench, the metal trench covers are put on top, then you put the floor carpet or tile on top of that.
This particular installation is a standard office building, so each user will have a 1-2 computers, a phone, personal power strip, etc. No medium voltage equipment, but likely some small desktop UPS systems.
There have been some recent discussions (for this project) that code might require the raised floor and/or the metal cable trench covers to be grounded. The problem we are having is the inspector does not have experience with this type of raised floor (honestly do not know if he has any experience with any type of raised floor) and is taking a very conservative interpretation of the code.
Can anyone recommend what to do? The floor manufacturer tells us that 99.9% of their customers do not require grounding but did say it is ultimately up to the local code and inspector. The project engineer apparently did not consider there to need to be grounding because it wasn't shown on any drawings and is deferring to the inspector.
Thank you very much for your help!
PS- This is for a project located in the U.S.