This afternoon, I pulled out my 2002 copy of NEC and found the section
applicable to what we have been discussing. I suggest that those who
rail at my stupidity and tell me how wrong I am do the same. It is
chapter 250.32. Exhibit 250.16 applies directly to my installation, and
shows only phase and neutral run between buildings, with neutral bonded
in both buildings.
Poking around for a while with google, I learned that 250.32 was,
indeed, changed in the 2011 edition to require that the ground conductor
be carried between buildings, but installations like the one I described
are specifically permitted provided that they comply with previous
editions of the Code. The 2014 edition of the code spells out that
exception in greater detail.
Here's the relevant section of the 2014 NEC. When reading it, remember
that "the grounded conductor" and "the grounded circuit conductor" refer
to the Neutral, and "the Equipment Grounding Conductor" is "the green
wire."
= = = = = =
250.32Buildings or Structures Supplied by a Feeder(s) or Branch
Circuit(s).
(A)Grounding Electrode.
Building(s) or structure(s) supplied by feeder(s) or branch circuit(s)
shall have a grounding electrode or grounding electrode system installed
in accordance withPart III of Article 250
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/iii--grounding-electrode-system#0cea2eaa64664fc8b71aa9edb947622a>.
The grounding electrode conductor(s) shall be connected in accordance
with250.32(B)
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/ii--system-grounding#15e3af26e92e4c9e9a46b550b86d2c34>or(C)
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/ii--system-grounding#a17b15ce47544c399d6ac94585a70de6>.
Where there is no existing grounding electrode, the grounding
electrode(s) required in250.50
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/iii--grounding-electrode-system#715ca3f2213743d8b1c39e012350acf5>shall
be installed.
/Exception: A grounding electrode shall not be required where only a
single branch circuit, including a multiwire branch circuit, supplies
the building or structure and the branch circuit includes an equipment
grounding conductor for grounding the normally non—current-carrying
metal parts of equipment./
(B)Grounded Systems.
(1)Supplied by a Feeder or Branch Circuit.
An equipment grounding conductor, as described in250.118
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/vi--equipment-grounding-and#4160cdae62a442cd9b30baba0a99655c>,
shall be run with the supply conductors and be connected to the building
or structure disconnecting means and to the grounding electrode(s). The
equipment grounding conductor shall be used for grounding or bonding of
equipment, structures, or frames required to be grounded or bonded. The
equipment grounding conductor shall be sized in accordance with250.122
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/vi--equipment-grounding-and#e247a77a0d734de5b340f8f0c4b1ba74>.
Any installed grounded conductor shall not be connected to the equipment
grounding conductor or to the grounding electrode(s).
/ExceptionNo. 1:For installations made in compliance with previous
editions of this Code that permitted such connection, the grounded
conductor run with the supply to the building or structure shall be
permitted to serve as the ground-fault return path if all of the
following requirements continue to be met:/
1./An equipment grounding conductor is not run with the supply to the
building or structure./
2./There are no continuous metallic paths bonded to the grounding system
in each building or structure involved./
3./Ground-fault protection of equipment has not been installed on the
supply side of the feeder(s)./
/If the grounded conductor is used for grounding in accordance with the
provision of this exception, the size of the grounded conductor shall
not be smaller than the larger of either of the following:/
1./That required by220.61
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/iii--feeder-and-service-load#26da8323c5794538a81f4571c94b261d>/
2./That required by250.122
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/vi--equipment-grounding-and#e247a77a0d734de5b340f8f0c4b1ba74>/
/Exception No. 2:////If system bonding jumpers are installed in
accordance with////250.30(A)(1)
<https://www.inkling.com/read/national-electrical-code-2014-fire-protection-association/chapter-2/ii--system-grounding#0ced4916402044edbe29319bf4f95a2b>,
Exception No. 2, the feeder grounded circuit conductor at the building
or structure served shall be connected to the equipment grounding
conductors, grounding electrode conductor, and the enclosure for the
first disconnecting means./^^ //
Bottom line -- what I did in my buildings was according to Code in 2010
when I did it, and the installation is "grandfathered" by the 2011 and
2014 Codes. But it is not permitted now.
73, Jim K9YC
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