MECKLENBURG COUNTY
Land Use and Environmental Service Agency
Code Enforcement
3/14/12 ELECTRICAL CONSISTENCY MEETING
Code Consistency Questions
1. Does Section 210.4(B) apply to Article 517? For example a multiwire branch circuit feeding
a minimum of six receptacles for a patient bed location in a critical care area as required by
517.19(B). Would it be required to disconnect all ungrounded conductors of a multiwire
branch circuit permitted from the normal system?
Yes, Chapters 1 through 4 requirements apply to all portions of Chapter 5 unless specifically
addressed in the appropriate Article (NEC 90.3) Article 517 does not address this issue.
210.4(B) Disconnecting Means. Each multiwire branch circuit shall be provided with a means
that will simultaneously disconnect all ungrounded conductors at the point where the branch
circuit originates.
Note: Code Making Panel 15 has accepted a proposal at the ROP stage for the 2011 NEC, that
will not allow the use of multiwire branch circuits for patient care areas.
2. When installing a feeder to an outbuilding, ground rods will be installed, and 4-wire feeder
cable will be used to keep a floating neutral at the outbuilding panel isolated from the ground
bus. What is to be done if there also is a copper water line to this outbuilding that is common
to the first building where the service disconnect is located? Does that need to be bonded to
the feeder ground bus also?
Yes the metal water pipe needs to be bonded to the equipment ground bus. It does not
matter if the water pipe is “common” to both the building the service is in and the second
building. The answer is found in 250.104(A)(3) Multiple Buildings or Structures Supplied by a
Feeder(s) or Branch Circuit(s). This section requires the metal water piping system to be
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bonded in or at the building supplied by one or more feeders or branch circuits. The size of
the bonding jumper conductor is determined from Table 250.66 based upon the size of the
supply conductor.
3. A meter and service disconnect are being installed on the outside of the home and the
panelboard is 15 feet inside the basement. Can the main grounding conductor from the
exterior service disconnect be installed inside the EMT conduit along with the feeders,
through the panelboard and to the water pipe in one continuous length or should it remain
outside of the conduit?
This grounding electrode conductor is permitted to be installed inside or outside the EMT. If
installed inside, look at the rules in 250.64(E) which requires the grounding electrode
conductor to be bonded to the ferrous metal raceways and enclosures it passes through. Your
installation may be very difficult to do.
4. I have an outdoor housed generator set that is 35 feet away from the building being
served. There is main breaker (disconnect) at the generator location and a wall between the
building served and the generator. Is a disconnect also required at the building being served?
700.12(B)(6); 701.11(B)(5) and 702.11 states:
Outdoor Generator Sets. Where an outdoor housed generator set is equipped with a readily
accessible disconnecting means located within sight of the building or structure supplied, an
additional disconnecting means shall not be required where ungrounded conductors serve or
pass through the building or structure. The disconnecting means shall meet the requirements
of 225.36.
Also we need to look at the definition of “within sight”:
In Sight From (Within Sight From, Within Sight). Where this Code specifies that one
equipment shall be “in sight from,” “within sight from,” or “within sight of,” and so forth,
another equipment, the specified equipment is to be visible and not more than 15 m (50 ft)
distant from the other.
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5. A duplex dwelling has separate meters and load centers for each dwelling. A breezeway
separates the two dwellings. The breeze way has two luminaires. Can I feed one luminaire
from each dwelling?
210.25 Branch Circuits in Buildings with More Than One Occupancy.
(A) Dwelling Unit Branch Circuits. Branch circuits in each dwelling unit shall supply only loads
within that dwelling unit or loads associated only with that dwelling unit.
(B) Common Area Branch Circuits. Branch circuits required for the purpose of lighting, central
alarm, signal, communications, or other needs for public or common areas of a two-family
dwelling, a multifamily dwelling, or a multi-occupancy building shall not be supplied from
equipment that supplies an individual dwelling unit or tenant space.Article 210.25(B) stipulates
that common area branch circuits cannot be supplied from equipment that supplies an
individual dwelling unit.
6. I have a covered structure that is open on the side and is wired. Are the receptacles under
this covered structure required to have GFCI protection?
7. Can a 200-amp MLO power panel be fed with a 9’ tap from a 200-amp OCP device using a
#2 copper Type THHN and a heating load of 80 amps?
No, see 240.21(B). The installation described about meet neither the 10 ft or 25 ft tap rule.
NEC 240.21(B)(1) requires the conductor to be size not less than the device in which it
terminates (#2 is not large enough for a 200A panel). NEC 240.21(B)(2) requires the
conductors to terminate in an overcurrent device.
8. Is a service receptacle required in a furnace room located in the middle of a finished
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residential basement where there are receptacles in other rooms within 25’of the equipment?
If so does it need to be GFCI protected?
Yes, a service receptacle is required. A receptacle for a furnace must be in an
accessible location for servicing the equipment in accordance with 210.63. The
receptacle is required to be GFCI protected if required by its location in accordance
with 210.8. Where a flexible cord or cable would be required to be utilized in the
given scenario, the provisions of Article 400 also apply. It is not permitted to run
flexible cord through a doorway in accordance with 400.8(3).
9. An inspector rejects an island receptacle that is located under a counter top with an
overhang of 7”. The electrician installs another receptacle that is in compliance but leaves the
original rejected receptacle installed. Can it remain or does it need to be removed?
It can remain…but not a part of the small appliance branch.
10. Can a 50-ampere receptacle be fed by a 30-ampere circuit breaker?
Yes, as a 50-ampere circuit could not serve other than a 50-ampere rated receptacle, but a
50-ampere receptacle can certainly be protected by a lesser rated overcurrent device such as
a 30-ampere overcurrent device.
However, see Section 210.21 Outlet Devices, (B)
Receptacles, subparagraph (3) Receptacle Ratings, that states, “Where connected to a branch
circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the
values listed in Table 210.21(B)(3), or where larger than 50 amperes, the receptacle rating
shall not be less than the branch-circuit rating.”
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