ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
What does your work place look like?
by Lostazhell - 12/01/20 03:44 AM
Where is Everyone?
by gfretwell - 11/30/20 04:12 PM
Happy Thanksgiving
by gfretwell - 11/30/20 04:04 PM
From an outsider- How does tipping work?
by gfretwell - 11/30/20 04:00 PM
Ground fault remover :-)
by dsk - 11/30/20 03:51 AM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 15 guests, and 14 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Farm Sub Panel Grounding #202598 08/12/11 02:48 AM
Joined: Aug 2011
Posts: 1
S
Shaun Offline OP
New Member
It's my understanding that with all sub panels the ground and neutral remain floating or isolated from one another. The only bonding connection should exist at the main panel. Reason being, anything common between the house / garage / barn or whatnot could become energized should a neutral become open creating a shock hazard.

However, I am working on a farm location where there is a 100 amp overhead feed coming from the customers 200 amp service at their house, going to a 60 amp panel in a barn, and just before the barn their is a 70 amp rated sub panel mounted to a utility pole feeding receptacles. Their are no common conductive paths (by conductive paths I am referring to water / gas pipes or the like) between the house or the barn, and its quite a distance away. So given that there are no water or gas pipes that could become energized, is it a requirement to bond the neutral to the ground at the sub panel?

At the utility pole:
I'm wiring a 240v receptacle for a customer to feed a job trailer at the utility pole and noticed a couple things with the existing wiring to the receptacles:

First off, none of the receptacles had a ground wire. The only means of grounding they had were through the conduit fittings attached to the painted sub panel-box. I thought this was something not to be done, unless either the receptacles were marked as ungrounded or the ground prong was plugged.

Secondly, there are no ground rods around the utility pole. The only ground connection appears to be coming from an extra overhead conductor they ran from the barn panel to the pole mounted 70A sub panel. Is there not supposed to be a individual grounding electrode for each sub panel?

Thanks in advance,

Shaun


Last edited by Shaun; 08/12/11 02:51 AM.
Tools for Electricians:
Re: Farm Sub Panel Grounding [Re: Shaun] #202613 08/14/11 01:00 AM
Joined: Jul 2005
Posts: 183
J
jay8 Offline
Member
I would direct you to 10-208 for 2 or more buildings fed from a single service, and the rule talks specifically about buildings housing livestock. Essentially separate grounding electrode at each building, each panel neutral bonded to this electrode.

And you need the bond wire for the receptacles otherwise the 6/32 screws used to mount the recetacle become the bonding method which is not approved as per 10-804. Maybe refer also to 26-714 if the outdoor receptacles are part of a single family dwelling on the farm, ie GFCI protection.

Re: Farm Sub Panel Grounding [Re: Shaun] #202630 08/15/11 07:19 PM
Joined: Jun 2006
Posts: 613
M
mikesh Offline
Member
Building housing livestock must be grounded and the neutrals must be bonded.
Outlets require a bonding jumper from the box to the outlet as Jay said
Unless there is a pole mounted transformer there is no requirment to Ground any of the overhead wiring except in each building that houses livestock and at the main service all this is fed from. The bare neutral is grounded through the service when distributed overhead with Triplex.

Re: Farm Sub Panel Grounding [Re: Shaun] #202642 08/16/11 09:19 AM
Joined: Aug 2002
Posts: 402
J
jdevlin Offline
Member
Just to clarify the above post. Buildings housing livestock must have a ground electrode intalled. If the building does not house livestock the extra electrode is not required. All buildings must be grounded.


Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
AllClear
AllClear
Belmond Iowa US
Posts: 44
Joined: August 2005
Show All Member Profiles 
Top Posters(30 Days)
Trumpy 17
Popular Topics(Views)
272,150 Are you busy
206,031 Re: Forum
194,053 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3