Services Practice Questions

B. They are grouped, and each one is marked to indicate the load it serves

Grouping and marking live in 230.72, one section away from the count, and a question about where the disconnects sit relative to each other is answered there rather than in 230.71. The marking is on each disconnect and it names the load, not the ampere rating. The two sections sit close enough together that landing on the wrong one costs a re-read.

NEC 2026 230.72(A)

D. In a readily accessible location either outside the building or inside nearest the point of entrance of the service conductors

The location rule is split by occupancy in this edition, and everything other than a one-family or two-family dwelling keeps the older choice of outside or inside at the nearest point of entrance. The outdoor-only option belongs to the dwelling subdivision. Anywhere readily accessible inside is what the rule refuses, since it is the length of unprotected conductor inside the building that the section is managing.

NEC 2026 230.70

A. In a bathroom

The location subdivision closes with one flat prohibition and a bathroom is it. The other three are ordinary locations that the rest of the section governs by accessibility rather than by a ban. An item that describes a room is usually checking whether you know that the list of prohibited rooms has exactly one entry on it.

NEC 2026 230.70

C. 3 feet

The same 3 feet covers doors, porches, balconies, ladders, stairs, fire escapes and similar locations, and it applies to open conductors or multiconductor cable without an overall jacket. An exception releases conductors run above the upper level of a window, which is the case people are picturing when they answer that no clearance applies. The 10 foot figure belongs to the point of attachment rather than to a building opening.

NEC 2026 230.9

D. Not less than 10 feet

The point of attachment has to give the clearances of 230.9 and 230.24, and on nothing else may it fall below 10 feet above finished grade. That floor holds even where the graded clearance list would allow something lower over the surface in question. The 12 foot figure is a clearance over residential property and driveways, not an attachment height.

NEC 2026 230.26

B. Meters and meter sockets

NEC 230.82 is a closed list, and nothing that is not on it qualifies, which is what makes these items quick once you have read it. Meters and meter sockets are the first entry most people remember. Load that belongs on the load side of the disconnect, such as a panel or a lighting circuit, never appears on the list at any ampere rating.

NEC 2026 230.82

C. It is routed with the ungrounded conductors to each service disconnecting means and connected to the grounded conductor terminal or bus there

The grounded conductor at a service is the return path a fault needs, so Article 250 brings it to each disconnect whether or not any load uses it, with a main bonding jumper tying it to each enclosure. A three-wire load does not change that, because the requirement is about clearing a fault rather than about serving a load. This is the Article 250 rule that most often turns up inside an Article 230 question.

NEC 2026 250.24(D)

A. No, vegetation is not permitted to support overhead service conductors or service equipment

NEC 230.10 is one sentence with no exception attached to it, which makes it one of the cheapest points in the article. The strain relief answer borrows a permission that belongs to holiday lighting under the temporary installations article, where a tree may be used under stated conditions. Nothing about span length or the kind of property changes the answer here.

NEC 2026 230.10

A. No, since each of the two to six disconnects has to be in its own enclosure, panelboard, switchboard section or compartment

The permitted arrangements are a list, and every entry on it puts one disconnect in its own enclosure, panelboard, switchboard vertical section with barriers, switchgear compartment, metering center compartment or motor control center unit. Six handles sharing one main-lug can is the picture people carry from the older rule and it is not on that list. The count is the decoy in an item like this and the arrangement is the question.

NEC 2026 230.71(B)

C. An exception lets equipment installed under a previous edition keep as many as six disconnects in one enclosure

The exception is about time rather than about equipment, and it covers service equipment installed in compliance with previous editions that permitted multiple disconnects in a single enclosure, section or compartment. That is the panel you are standing in front of on a service change and not the one you are about to install. No ampere threshold appears anywhere in it.

NEC 2026 230.71(B)

D. Where an emergency disconnect is installed in accordance with the outside disconnect rule in Article 225

NEC 230.70(A)(1) puts the disconnect for a one-family or two-family dwelling in a readily accessible outdoor location, on the dwelling unit or within sight of it, and its exception releases that where an emergency disconnect complying with 225.41 is installed. The inside at the nearest point of entrance option belongs to buildings other than one-family and two-family dwellings. Nothing in the section turns on the ampere rating or on the utility.

NEC 2026 230.70, 225.41

B. It is identified as an emergency disconnect on the outside front of the enclosure, in white letters at least one half inch high on a red background

Every service disconnect gets marked as a service disconnect, and a one-family or two-family dwelling gets a second marking with the color, placement and letter height all specified. The load marking belongs to the grouping rule, where two to six disconnects each name what they serve. The outdoor location is what triggers the emergency marking rather than what excuses it.

NEC 2026 230.70

C. 8 feet 6 inches above the roof surface, held for 3 feet in all directions from the edge

The headline figure over a roof is 8 feet 6 inches, and the 3 feet in all directions from the edge is what keeps somebody from stepping off a parapet into it. Several exceptions hang off that number, which is why a roof question is rarely answered by the headline alone. The 3 foot vertical figure is one of those exceptions rather than the general rule.

NEC 2026 230.24(A)

A. 200 amperes

The rule adds the noncontinuous load to 125 percent of the continuous load, so 100 plus 100 is 200 amperes. Adding the two loads straight gives 180 and skips the increase entirely. Putting the increase on the noncontinuous half instead gives 205, and running the whole 180 up by 125 percent gives 225.

NEC 2026 230.42(A)(1)

B. There is no overcurrent device ahead of service-entrance conductors, so nothing on the premises will open on a fault in them

Service-entrance conductors sit on the supply side of the service disconnect, so the only thing that will clear a fault in them is the utility transformer. That single fact is behind the stack of rules that look arbitrary from the outside: the named wiring method list, the restrictions on splices, the marking on line side connectors and the seriousness of the bonding. Size and location are consequences of the installation rather than reasons for the rules.

NEC 2026 230.42, 230.46

D. 230.2

230.2 is titled for listing requirements in this edition and carries what earlier books held at 230.66(A), naming equipment that has to be listed outright and then requiring everything else to be listed or field evaluated. Number of Services moved out of 230.2 to 230.4 at the same time, and the rule about one building supplied through another moved to 230.5. In this edition 230.66 is the marking rule.

NEC 2026 230.2

D. One, unless one of the permissions in 230.4 applies

Number of Services is at 230.4 in this edition, and its subdivisions permit additional services for special conditions such as fire pumps and standby systems, for special occupancies by special permission, for capacity, and for different characteristics. An option pointing at 230.2 is pointing at the listing rule, which is exactly the swap this edition created. Where a building has more than one supply, a plaque or directory at each service disconnect location is part of the package.

NEC 2026 230.4

B. Services supplying dwelling units, dormitories, guest rooms and guest suites, patient sleeping rooms in nursing homes and limited-care facilities, and sleeping quarters in fire, police, ambulance, rescue and ranger stations

The list is built around places people sleep rather than around ampere ratings, and it reaches well past the one-family dwelling that candidates remember. The device is an integral part of the service equipment or sits immediately next to it, it is a Type 1 or Type 2, and it carries a nominal discharge current rating of at least 10 kA. Replacing service equipment brings the whole section along with it.

NEC 2026 230.67

A. 12 feet

The list in 230.24(B) is graded by the surface underneath and by voltage to ground, and residential property and driveways at not over 300 volts to ground sit at 12 feet. Raise the voltage above 300 volts to ground over the same surface and the figure becomes 15 feet. The 18 foot entry belongs to public streets, alleys, roads and parking areas subject to truck traffic. The 10 foot entry carries more conditions than the rest, reaching the service entrance and pedestrian-only areas for conductors cabled together with a grounded bare messenger at not over 150 volts to ground.

NEC 2026 230.24(B)

C. A disconnect that is part of listed equipment and used only to disconnect a surge-protective device

NEC 230.71 names a short list of devices that do not count, and every one of them is part of listed equipment and used solely for one job: power monitoring, a surge-protective device, the control circuit of a ground-fault protection system, or the control circuit of a power-operable service disconnect. That is how a listed assembly can carry what looks like a seventh handle and still comply. A fire pump is handled by the number of services and grouping rules instead, which is a different mechanism entirely.

NEC 2026 230.71

B. A reduction in clearance to 3 feet

This exception needs both conditions before it pays out: not over 300 volts between conductors and a slope of at least 4 in 12. The 18 inch figure belongs to a different exception, the one covering a short run above a roof overhang that terminates at a through-the-roof raceway. A guarded or isolated roof area is a third exception that reaches the same 3 feet by another route, which is why reading the number without the condition is unsafe here.

NEC 2026 230.24(A)

C. Where they terminate on an overcurrent device and both the device and its assembly are listed for operation at 100 percent of their rating

The listing has to sit on the assembly as well as on the device, so a breaker marked for continuous duty on its own does not get you there. A second exception in the same place lets a grounded conductor that is not connected to an overcurrent device be sized at 100 percent, which is a separate case. A load that is entirely noncontinuous never triggered the increase, so the exception has nothing to release.

NEC 2026 230.42(A)(1)

D. A short-circuit current rating at least equal to the available fault current, the capability to interrupt the load served, and a field marking on the exterior saying it is not service equipment

The supply side list carries conditions on several of its entries, and the meter disconnect switch has three of them attached. The marking exists so that nobody standing in front of it mistakes it for the service disconnect, which is why it is field marked on the exterior in a manner suitable for the environment. The meter-mounted transfer switch entry just below it carries a parallel set of conditions.

NEC 2026 230.82

A. 30 amperes

The section grades the floor by what the service supplies: 15 amperes for limited loads on a single branch circuit, 30 amperes for not more than two 2-wire branch circuits, 100 amperes for a one-family dwelling, and 60 amperes for everything else. All four sit under a first sentence that also requires the rating to be not less than the calculated load, so the floor is a floor and never an answer by itself. Where the disconnect is more than one switch or breaker, their combined ratings meet the same figure.

NEC 2026 230.79

D. Ground-fault protection of equipment on each service disconnect rated 1000 amperes or more

The trigger is a solidly grounded wye system over 150 volts to ground but not over 1000 volts phase to phase, with a disconnect rated 1000 amperes or more, and 480Y/277 at 1200 amperes meets all of it. The rating used is the largest fuse that can be installed or the highest continuous trip setting the breaker can be adjusted to, not the setting somebody left it at. Protection for equipment and protection for personnel are different devices looking for different things.

NEC 2026 230.95