Commercial Plan Review
Land Use and Environmental Service Agency
(Code Enforcement)
Electrical Q&A 2010
Second Quarter 2010
General:
1.
(Q) During plan review what documentation is required when the exception
is used in 230.72(C) and 240.24(B)?
(A) The drawings are the documentation and the exception would be applied only when
the tenant spaces in a multi-tenant building are under the property management utility
metering. In other words, the landlord provides utility power to each space.
2.
(Q) When is a drawing submitted to commercial electrical plan review for examination
not required to be sealed by a registered design professional?
(A) For permitting purposes, the seal of a registered design professional is not required
when the building, structure or project involved does not have a total cost of construction
exceeding $90,000 or the total building area does not exceed 2,500 square feet in gross
floor area. There are certain conditions under which these exemptions may not apply.
There are other exemptions that may apply on a particular type of project so check the
state statues.
3.
(Q) When is it necessary for an Architect or Engineer to seal their drawings?
(A)Questions concerning this should be directed to the North Carolina Board of
Architecture or the North Carolina Board of Examiners for Engineers and Land
Surveyors. However, as a general rule the registered design professional must seal, sign
and date each sheet of the original drawings issued for bidding, permitting and
construction.
4.
(Q) (a) Can an electric fire pump have more than one over current protection device
(OCPD) on the emergency side?
(b) If so, under what conditions?
(c) Must all upstream OCPD be rated at locked rotor current?
(A) (a) No, unless required by other parts of the code.
(b) Example NEC 225.31.
(c) No, see NEC 695.4b.
5.
(Q) A drawing shows a one line with a 400 amp, 3 phase feeder in parallel
sets of 3/0 conductors in the same raceway.
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(a) Does this comply with the NEC?
(b) How do you size the equipment ground?
(A) (a) Yes. With derating per Table 310.15(B)(2)(a) and also adjustment of the OCPD.
(b) Using NEC 250.122.
6.
(Q) Per NEC 210.4(B) all ungrounded circuits of a multiwire circuit have to
open simultaneously at the breaker. How do you handle this requirement in a Patient
Care area of a Health Care facility where when a breaker trips and takes out
two additional circuits?
(A) The NEC does not make any provisions for this problem. This design issue could be
resolved if the design professional did not allow multiwire circuits and required
individual neutrals.
7.
(Q) A design professional wants to locate the lighting and branch circuit panels over an
elevated platform. The platform will have a wall mounted, fixed in place, ladder
(not a stairs) to access the panel and overcurrent protection from the floor level.
Is this acceptable?
(A) Yes. This meets the intent of NEC 100 I. for “readily accessible” along with NEC
240.24 (A) & (B) and NEC 404.8 (A).
8.
(Q) (a) Are arc-fault receptacles required in the guest rooms of hotels and motels?
(b)What if permanent cooking equipment is present in these guest rooms?
(c)What is considered “permanent” cooking equipment?
(d)If there is permanent cooking equipment present in the guest rooms would the
over current protection devices (OCPD) be required to be located in the same
room?
(A) (a)No.
(b)Yes per NEC 210.18.
(c)Fixed in place such as a cooktop or range.
(d)Yes per NEC 210.12(B), 210.18 and 240.24(B).
9.
(Q) (a) A heat tape system is installed on a metal roof, and there is a GFCI service
outlet for rooftop units available on this roof. Can this GFCI service outlet be
used to feed the heat tape system, or should another circuit be provided that is not GFCI
protected?
(b) Would this same ruling apply if the heat tape system was installed in a
walk-in freezer?
(c) Would this same ruling apply if the heat tape system was installed in the protective
box for a backflow preventor?
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(A) (a) No. Per NEC 210.8(B)(3), 426.28 and 427.22 the service outlet is for
ground fault personnel protection rated at 5ma. The protection referred to in 427.22 is
GFCEP and is rated at 27 to 30ma. The purpose is to protect the equipment and premises
from fire due to overheating of the heat tape. The GFCI at 5ma would cause nuisance
tripping.
(b)Yes. The ruling would be the same.
(c)Yes. The ruling would be the same.