ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Extension cords
by annemarie1. 09/25/18 06:06 PM
220/230/240V 60Hz Systems
by gfretwell. 09/23/18 02:50 PM
Inspection camera help
by petey_c. 09/22/18 07:52 AM
Motion detectors and dimmers
by gfretwell. 09/20/18 04:02 PM
Acronis Backup 2017
by gfretwell. 09/16/18 12:46 AM
New in the Gallery:
Plug terminals
Housebilding DIY wiring
Who's Online Now
0 registered members (), 8 guests, and 17 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
metal roofs #96009
10/30/05 03:17 PM
10/30/05 03:17 PM
watersparkfalls  Offline OP
Member
Joined: Mar 2005
Posts: 222
Washington...Not DC
where does everybody stand on bonding metal roofs? the code i beleive but cant quote says any metal that may become energized shall be bonded, i always bond steel and tin but am working on a house which will have a metal roof and am wondering if i need to bond the roof?

thoughts comments always appreciated.
thanks,
h20

2017 / 2014 NEC & Related Books and Study Guides
Re: metal roofs #96010
10/30/05 05:40 PM
10/30/05 05:40 PM
J
jw electric  Offline
Member
Joined: Sep 2005
Posts: 106
Asheboro, NC
Read the first sentence and see it you think it fits.

250.104 (C) Structural Metal. Exposed structural metal that is interconnected to form a metal building frame and is not intentionally grounded and is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 and installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible.


Mike
Re: metal roofs #96011
10/30/05 08:07 PM
10/30/05 08:07 PM
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
I must disagree. As I understand the term, "structural metal" is something like an I-Beam; simple sheet metal roofing would not qualify.

More to the point....in a conventional steel building- I beam frame, sheet metal siding and roof- with all those screws and bolts, it would be darn near impossible to avoid bonding a piece of metal.

Re: metal roofs #96012
10/30/05 08:17 PM
10/30/05 08:17 PM
G
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
I agree with Reno. But tell me- was I mistaken or were we using the '02 code for our discussion here unless specified other editions? This thread is directing us to the '05 code???


George Little
Re: metal roofs #96013
10/30/05 08:42 PM
10/30/05 08:42 PM
H
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Just for kicks, lets throw this one in here. If the whole house is made of wood, but there is 1 steel I-beam running down the center of the house. Would you bond that I-beam to the electrical wiring?

Re: metal roofs #96014
10/30/05 09:07 PM
10/30/05 09:07 PM
E
Electricmanscott  Offline
Member
Joined: Jan 2002
Posts: 1,457
Holden, MA USA
Harold to answer your question, no I would not bond it and no it would not be required to be bonded nor would a metal roof.

Re: metal roofs #96015
10/31/05 12:52 AM
10/31/05 12:52 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,290
Estero,Fl,usa
I always looked at the intent that metal that may become energized could be bonded to the EGC of the circuit likely to energize it.
The caddy clamp that holds the box to the beam was usually enough to make me happy. The tricky one is aluminum siding where you have isolated sections with a box on it like a gable end on a CBS house with a flood light.


Greg Fretwell
Re: metal roofs #96016
10/31/05 09:05 PM
10/31/05 09:05 PM
H
HLCbuild  Offline
Member
Joined: Dec 2004
Posts: 209
Herndon,Va USA
The metal roof is a "roof covering", not part of a structural metal frame...no bonding required

Re: metal roofs #96017
10/31/05 09:57 PM
10/31/05 09:57 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,290
Estero,Fl,usa
The commentary after 250.116 sums up my opinion.
Quote
Because metal siding on buildings is not electrical equipment, it is outside the scope of the Code [see 90.2(A)]. Therefore, the Code cannot require that it be grounded. Quite often, however, luminaires, signs, or receptacles are installed on buildings with metal siding that could become energized. Grounding of metal siding reduces the risk of shock to persons who may come in contact with the siding.


My take was always that if the attached equipment was electricaly connected to the metal material it was bonded. In the case of a roof I would feel the same way. If equipment is installed up there, bond the roof to the EGC of the equipment. It would usually be hard not to if the equipment is metal.


Greg Fretwell

Featured:

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

 

Member Spotlight
mersadrad
mersadrad
Montreal, Quebec, Canada
Posts: 28
Joined: March 2011
Show All Member Profiles 
Top Posters(30 Days)
Admin 13
BigB 4
Popular Topics(Views)
249,474 Are you busy
187,390 Re: Forum
176,732 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.030s Queries: 14 (0.010s) Memory: 1.0025 MB (Peak: 1.1716 MB) Zlib enabled. Server Time: 2018-09-26 08:44:51 UTC