Proper Bonding at Sub-Panel

Originally Posted By: pdickerson
This post was automatically imported from our archived forum.



http://www.nachi.org/bbsystem/usrimages/G/Garage_Left_Bus_Bar1.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/G/Garage_Left_Bus_Bar2.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/G/Garage_Panel.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/G/Garage_Right_Bus_Bar.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/M/Main.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/S/SE_Bus_Bar.JPG ]


[ Image: http://www.nachi.org/bbsystem/usrimages/S/Service_Disconnect.JPG ]


Originally Posted By: jpope
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I see a four wire feed leaving the SE, no? It looks like three large cables and a bare copper leaving out the lower conduit. If so, the copper is the EGC for the garage panel. Neutrals would be required to be isolated.


Otherwise, you're right. I don't see the bond on the left bus either.


--
Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738

Originally Posted By: rcooke
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Here in Canada you are only allowed a Ground at the main panel . All pony panels must be fed with 2 hots a neutral and a ground . If you feed with a three wire only you can get all sorts of strange thinks happening .


Years ago when it was allowed to be fed with three wire I heard of a spot where the horses wound not go they could feel in there Hooves the electricity and would not drink out of the water trough .


Roy Cooke sr


Originally Posted By: pdickerson
This post was automatically imported from our archived forum.



Jeff,


The bare copper wire connects to a grounding rod at the base of the meter pole. It does not go to the garage.


Originally Posted By: Greg Fretwell
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I have problems with seeing stuff in pictures but if this is really just a 3 wire feeder and there are no other paths it is a virtual main disconnect for bonding rules.


If the bonding screw is in, on the neutral bus it is “legally” bonded to the supplimental grounding bus, screwed into the can. I really like to see a 250.66 sized wire between them tho. (#4cu in this case)


Originally Posted By: tgettier
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I know that this is a little late but for what it?s worth. In a NORMAL sub panel set up.


You have 3 conductors coming in from the street 2 hot and a neutral they are going to your main panel. You will have a ground wire running to an earth ground from that same panel. The neutral and ground branch circuits can share a common bus which should be bonded to the panel. Now when you add your Sub panel it can be done several different ways and still be to NEC the two most common are.
1. There are 4 conductors run 2 hot 1 neutral 1 ground.
2. There are 3 conductors run 2 hot 1 neutral and a driven ground rod or equivalent
The neutral and ground MUST be on separate buses in the SUB panel with the Ground bus bonded to the panel.
The reason for this is if the Sub panel was to lose the neutral and you have the Ground and neutral conductors sharing bus you ?could? then have ground wires caring voltage.


Originally Posted By: Greg Fretwell
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when you have a sub panel in a separate building with no other metalic paths back to the main building you can still have a 3 wire feeder and reground the neutral in the second building.


![](upload://qkU1xzD8lPm6yCxoRSqI6tCuAbw.jpeg)