E2 Plan Review and Inspections 3

Question 1

During a plan review, an inspector sees that the one-line diagram shows a 2000A service with a single 2000A disconnect.
The building also has an emergency generator.
Which NEC section governs the number and grouping of service disconnects?

Accepted Answer

NEC 230.71, which limits service disconnecting means to a maximum of six disconnects

Answer

NEC 230.82, which permits up to ten disconnects for large commercial buildings

Answer

NEC 700.12, which governs emergency system power supply

Answer

NEC 225.33, which addresses outdoor feeder disconnects

Question 2

An inspector is reviewing plans for a restaurant kitchen and notices that the equipment grounding conductors for all circuits are shown as the same size. What potential issue should be investigated?

Accepted Answer

NEC 250.122 requires EGCs to be sized based on the rating of the overcurrent device protecting each circuit

Answer

Equipment grounding conductors must all be the same size per NEC 250.122

Answer

The issue is only relevant if circuits exceed 100A

Answer

Equipment grounding conductor size is determined solely by the phase conductor size

Question 3

A commercial plan review shows a 208Y/120V panelboard feeding a dedicated computer room. The plans indicate that isolated ground receptacles will be installed. What must the inspector verify on the plans?

Accepted Answer

That the isolated ground circuit includes an insulated equipment grounding conductor run back to the panel, and the panel enclosure is still grounded

Answer

That the isolated ground receptacles are connected to a separate grounding electrode system

Answer

That all circuits in the computer room use isolated ground receptacles only

Answer

That the isolated ground system is connected directly to building steel

Question 4

While reviewing commercial plans, an inspector finds that a rooftop HVAC unit disconnect is shown mounted on the rooftop adjacent to the unit. The unit is fed by a 460V feeder. Which requirement is most critical to verify?

Accepted Answer

That the disconnect is located within sight of the unit and is readily accessible per NEC 430.102

Answer

That the disconnect enclosure is rated for outdoor, wet locations (NEMA 3R or better)

Answer

That the feeder conduit is rigid metal conduit only on rooftops

Answer

That a ground fault circuit interrupter is installed for the disconnect

Question 5

During a rough-in inspection of a commercial building, the inspector observes that flexible conduit (FMC) is used for the final connection to a rooftop air handler. The run is 10 feet long. What NEC requirement applies?

Accepted Answer

FMC over 6 feet requires a bonding jumper per NEC 250.118 since it may not provide an adequate ground path

Answer

FMC is limited to 6 feet for equipment connections per NEC 350.30(A)

Answer

FMC cannot be used for equipment above 277V

Answer

No limitation applies as long as the conduit is secured every 4.5 feet

Question 6

A commercial plan review reveals that all branch circuit conductors are shown as 12 AWG copper. Some circuits have 30A breakers for dedicated equipment. What code issue does this present?

Accepted Answer

12 AWG copper is only rated for 20A overcurrent protection per NEC 240.4(D), so 30A breakers are not permitted

Answer

12 AWG is acceptable for up to 30A if rated at 90°C

Answer

30A breakers are allowed on 12 AWG if the equipment nameplate requires it

Answer

The 30A breakers are acceptable if AFCI protection is provided

Question 7

An inspector reviewing plans for a commercial office building sees that receptacle circuits in an open office area are not shown with AFCI protection. The building is a new 2023 NEC project. What should the inspector require?

Accepted Answer

The inspector should verify the applicable edition of the NEC adopted locally, as AFCI requirements for commercial have expanded in recent editions

Answer

AFCI is only required in dwelling units and does not apply to commercial offices

Answer

Require AFCI on all receptacle circuits since the 2023 NEC mandates it for all occupancies

Answer

No action is needed since commercial spaces are exempt from AFCI requirements