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Thread: Bonding screw ?? Here I go Again
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02-25-2015, 06:23 PM #1
Bonding screw ?? Here I go Again
I have a main service panel, 200 amp Square D panel, the grounds and neutrals are on there own separate bars. Should the bonding screw (green screw) be screwed into the panel enclosure ? I hope I said that correctly.
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02-25-2015, 06:37 PM #2
Re: Bonding screw ?? Here I go Again
Trusting that the panel with the main is indeed the service equipment (basically, that is the first disconnect after the meter and shut the entire structure off), then, yes, the green bonding screw in the neutral terminal bar should be screwed into its threaded hole in the back of the enclosure.
The separate grounding terminal bars have the grounds bonded to the enclosure, which grounds the enclosure, so now what is left to do is to bond the neutral to the enclosure - and that is what that green bonding screw does.
However ... that multiple tap of that main green grounding conductor and the bare conductor is not right - that terminal is most likely rated for one and only one conductor, and for terminals which are rated for two grounding conductors, the rating will be (almost always will be) for two of the same size conductors.
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02-25-2015, 06:42 PM #3
Re: Bonding screw ?? Here I go Again
Jut remembered something important, this is NOT the main service disconnect it was located on the side of the house.
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02-25-2015, 06:45 PM #4
Re: Bonding screw ?? Here I go Again
That is a VERY IMPORTANT thing you just remembered ... ... in which case that green bonding screw should NOT be screwed into the back of the enclosure.
So, that disconnect is just serving as a "panel main" in that it shuts the panel off - good safety feature not required by code, but a good safety feature.
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02-25-2015, 07:23 PM #5
Re: Bonding screw ?? Here I go Again
What JP said. But he forgot to call it a sub panel.
Clue #1, Neat and tidy professional work, #2, Neutrals and ground carefully separated in the USA, where that is not required at the main disconnect, #3, a part left over but left for the inspector to find.
It is a remote distribution panel.
John Kogel, RHI, BC HI Lic #47455
www.allsafehome.ca
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02-26-2015, 06:13 PM #6
Re: Bonding screw ?? Here I go Again
In addition to the above, something I keep going back to in those photos ... rather, something NOT in those photos ... something which might be there but is not shown.
The feeder conductors are shown as two conductors on the ungrounded conductor main terminals and one conductor on the grounded conductor main terminal ... but where is the groundING conductor which is run with - supposed to be run with - those feeder conductors?
Is that green ground conductor it? Or that bare ground conductor? Or was the conduit the conductors are run in metallic and is serving as the ground conductor? And, if neither the green ground conductor or the bare conductor are that conductor ... what are they for?
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02-27-2015, 06:38 AM #7
Re: Bonding screw ?? Here I go Again
I am really bothered by something here and maybe it is the magic of photography but is the middle wire smaller ? second issue I have is we have a three phase panel (doubt) or the neutral is not identified by having white tape on the end
Looks like someone did a nice neat job - I just like to see wires properly identified
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02-27-2015, 03:18 PM #8
Re: Bonding screw ?? Here I go Again
Yes it is.
Decades ago, as I recall, that used to be permitted automatically - the neutral used to be permitted to be two sizes smaller as it only carried the unbalanced current.
Then along came harmonics and the realization that the neutral could actually be carrying much more current than previously thought.
(Added with edit: Now, one must do a calculation which supports installing a neutral which is smaller than the hot conductors.)
second issue I have is we have a three phase panel (doubt) or the neutral is not identified by having white tape on the end
I was wondering when someone would mention that the neutral conductor was not re-identified to white.
Last edited by Jerry Peck; 02-27-2015 at 03:33 PM. Reason: see (Added with edit: ... ) part
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02-27-2015, 05:11 PM #9
Re: Bonding screw ?? Here I go Again
It is always wise to include the reason(s) why a code requirement exsists.... inquiring minds?
Bonding the ungrounded conductor down stream, or after the service disconnect, will result in the unbalanced load to Davide and run on the grounding (earth) conductor also.
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It is always wise to include the reason(s) why a code requirement exsists.... inquiring minds?
Bonding the ungrounded conductor down stream, or after the service disconnect, will result in the unbalanced load to Davide and run on the grounding (earth) conductor also.
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02-27-2015, 10:32 PM #10
Re: Bonding screw ?? Here I go Again
Definitely no screw. How about all of the doubled neutral wires, they should each be under their own lug
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Definitely no screw. How about all of the doubled neutral wires, they should each be under their own lug
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02-28-2015, 07:08 AM #11
Re: Bonding screw ?? Here I go Again
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02-28-2015, 10:29 AM #12
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