ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Changing a Bulb
by gfretwell. 07/14/18 03:12 PM
Tray cable?
by gfretwell. 07/11/18 10:18 PM
Eaton Heavy Duty 30A and 60A Safety Switches
by Admin. 07/11/18 09:49 PM
ORTOVOX Recalls Avalanche Transceivers
by Admin. 07/11/18 09:44 PM
Tingle off the water spigot
by gfretwell. 07/08/18 12:58 PM
New in the Gallery:
Plug terminals
Housebilding DIY wiring
Who's Online Now
0 registered members (), 18 guests, and 15 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
raised floor grounding #174671
02/11/08 12:32 PM
02/11/08 12:32 PM
J
jrvazzer  Offline OP
Junior Member
Joined: Oct 2005
Posts: 4
ny,ny usa
Does the NEC have grounding requirement for raised floor in genral office space not IT or Data center.


jrv
2017 / 2014 NEC & Related Books and Study Guides
Re: raised floor grounding [Re: jrvazzer] #174673
02/11/08 12:54 PM
02/11/08 12:54 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,242
Estero,Fl,usa
No but your IT guy probably does. The only time the NEC would be involved is if you said it was "likely to be energized". (you do need the bezels on penetrations)
IT folks still want it grounded for noise suppression reasons.
Also note 645.2 and understand that most of the things you can get away with in a real data center under the floor is limited to that occupancy. Once you leave the computer room you lose a lot of that leniency. This becomes important when they convert old computer room space to office space. You should really be blocking off the HAVC between them and leaving a lot of that "free fire zone under the floor" mentality behind. I have seen AHJs who wanted all solid tiles installed and absolutely no wiring under the floor that wasn't in a chapter 3 wiring method.


Greg Fretwell
Re: raised floor grounding [Re: gfretwell] #174674
02/11/08 01:26 PM
02/11/08 01:26 PM
J
jrvazzer  Offline OP
Junior Member
Joined: Oct 2005
Posts: 4
ny,ny usa
Thanks for you respond.
We have a situation, where the tenant wanted to do renovation to his floor. (Not the first time) The floor is raised about 6" no HVAC just power and tel com wiring. The AHJ notice that the floor was not grounded, and mentions that the raised floor should be grounded. This tenant has occupied this facility for about 15 years. Is he forced to pay for the grounding of this floor base on IT requirements or NEC or is it AHJ. Their are 50 other floors in this building all having raised floors. Now, at this renovation the AHJ wants us to ground this floor.
One contractor quoted a high price for this work, other are quoting a smaller amount. The question is what requirement or standards do we use to properly design and satisfied AHJ and also have a uniform drawings so that all contractor can be on the same page when biding.


jrv
Re: raised floor grounding [Re: jrvazzer] #174701
02/12/08 12:28 AM
02/12/08 12:28 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,242
Estero,Fl,usa
Does the AHJ want old time system 390 level bonding with 2 gauge or larger copper to every post or is he just looking for a EGC from the wiring method under the floor to one or two places in the floor in some misguided reading of 250.104?
I would want to hear the article he is citing.
I think you should be able to go right from a metal box on each circuit to the floor, using the "circuit likely to energize" logic.

Around here the real question would be what is under that floor and how are you getting up into the office? Stringing power cords through floor penetrations is not compliant as soon as you leave article 645 space.


Greg Fretwell
Re: raised floor grounding [Re: gfretwell] #174721
02/12/08 03:15 PM
02/12/08 03:15 PM
G
ggardiner  Offline
Member
Joined: Oct 2001
Posts: 81
Calgary, Alberta Canada
Check with the flooring manufacturer for their recommended grounding instructions they may have the paper work to prove it does not need grounding in your area, or what the minimum requirement mght be. Even a 15 year old floor should be able to track down. I get requests all the time for grounding details for raised flooring that my company builds.

Re: raised floor grounding [Re: gfretwell] #174722
02/12/08 03:33 PM
02/12/08 03:33 PM
J
jrvazzer  Offline OP
Junior Member
Joined: Oct 2005
Posts: 4
ny,ny usa
Thanks. I could have asked him that but I didn't want to make it worst. I agree that there should be grounding, but to what extend. The floor is also being carpet so there is little chance of making contact with an energize floor.


jrv
Re: raised floor grounding [Re: jrvazzer] #174730
02/12/08 07:13 PM
02/12/08 07:13 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,242
Estero,Fl,usa
Is this a stringer floor or just posts? A bolted together stringer floor could be grounded with a single wire.


Greg Fretwell
Re: raised floor grounding [Re: gfretwell] #174768
02/13/08 10:02 AM
02/13/08 10:02 AM
J
jrvazzer  Offline OP
Junior Member
Joined: Oct 2005
Posts: 4
ny,ny usa
Yes, thanks that is exactly what the AHJ accepted.


jrv

Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Lostazhell
Lostazhell
Bakersfield, CA (Originally Orange Co.)
Posts: 1,431
Joined: February 2004
Show All Member Profiles 
Top Posters(30 Days)
Admin 5
Popular Topics(Views)
248,123 Are you busy
185,580 Re: Forum
174,902 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.021s Queries: 15 (0.004s) Memory: 0.9943 MB (Peak: 1.1599 MB) Zlib enabled. Server Time: 2018-07-19 03:58:31 UTC