Switches, Receptacles, Cord Connectors, and Caps

Based on the 2014 NEC^®

By Mike Holt, NEC Consultant

Articles 404 and 406 provide the requirements for some of the most commonly connected branch circuit devices.

The requirements of Article 404 apply to switches of all types, including snap (toggle) switches, dimmer switches, fan switches, knife switches, circuit breakers used as switches, and automatic switches, such as time clocks and timers.

The 2014 NEC heavily revised the requirement for having a neutral at switch locations. Why so much change? When a new, significant rule comes into the NEC, it often takes at least another revision cycle to work out the kinks because it’s difficult to anticipate every type of installation that a new rule will affect.

The 2014 NEC greatly expanded the areas where a neutral isn’t required, and it significantly cleans up the existing exceptions.

It also removed the text regarding framing cavities that are “open at the top or bottom” because even Code experts disagreed about what that exception meant. The 2014 NEC replaced that text with item two, which is easier to understand:

402.2(2) Where the switch box can be accessed to add or replace a cable containing a neutral without damaging the finish of the building.

Additional new allowances include 3-way and 4-way switches where the switches can “see” the entire room. In these instances, an occupancy sensor would be installed only at one or the other switch so there’s no reason to require a neutral at both.

Mounting snap switches

Unfortunately, it’s a common (and unsafe) practice to use drywall screws to attach receptacles and switches to boxes. Another bad, and probably more dangerous, practice is that of attaching luminaires to boxes using screws that weren’t designed, tested, and listed to support them. The NEC prohibits both of these practices.

When you install a snap switch in a recessed box, you must firmly seat the ears of the switch yoke against the finished wall surface. Screws for attaching a snap switch to a box must be machine screws matching the thread gage or size of the screw holes in the box, unless otherwise allowed by the manufacturer’s instructions or unless part of a listed assembly [404.10(B)].

Note that this same screw requirement now applies to receptacles, also [406.5]. And for similar reasons.

Receptacle rating and type

It’s becoming common for energy management systems to control receptacles in commercial buildings. These systems de-energize receptacles at a certain time of day, such as just after quitting time. But quitting time isn’t the same for everybody, so this presents a problem. Especially when equipment such as a computer workstation is plugged into one of those receptacles.

Now, all nonlocking, 125V, 15A and 20A receptacles that have an automatic means to remove power from the outlet (e.g., for energy management or building automation) must be marked with a specific “controlled receptacle” symbol placed on the receptacle. This symbol must be visible to users, so choose the location for the symbol with that in mind [406.3(E)].

You don’t have to use this marking on wall switch-controlled receptacles used for lighting. See also [210.70(A)(1) Ex 2].

Grounding type

Previous editions of the NEC provided the rule that receptacles must be of the grounding type but stated it as an exception. Now the requirement is in the opening statement of 406.4(A) and the NEC states it in positive text. This is just one more effort in the long quest to change the NEC from the “National Exceptions Code” back to the National Electrical Code.

Receptacles installed on 15A and 20A branch circuits must be of the grounding type, unless used for replacements as permitted in (D)(2). Single receptacles must have an ampere rating not less than the rating of the branch circuit [210.21(B)(1)]. Multioutlet receptacles (such as duplex receptacles) must have a rating compliant with Table 210.21(B)(3) [406.4 (A)].

No face up

The NEC now prohibits installing receptacles face up in any countertop, not just those in dwelling units [406.5(E)]. The logic behind this now extends to seating areas and similar surfaces, with the new subsection (F) providing the requirements.

Why doesn’t this change apply to all floor receptacles? Floor boxes are typically listed without the receptacle, so they aren’t a listed assembly. Rather, they’re an assembly of listed parts.

Damp or wet locations

All 15A and 20A receptacles installed in a wet location must be within an enclosure that’s weatherproof when an attachment plug is inserted [406.9(B)(1)]. All nonlocking type 15A and 20A, 125V and 250V receptacles in a wet location must be listed as weather resistant. Receptacles rated 30A or more installed in a wet location must comply with (a) or (b):

(a) Wet Location Covers. A receptacle in a wet location, where the load isn’t attended while in use, must be installed in an enclosure that’s weatherproof when an attachment plug is inserted.

(b) Damp Location Covers. A receptacle (in a wet location) that will be used only while someone is in close proximity (e.g., one used with portable tools) can have an enclosure that’s weatherproof when the attachment plug is removed and the cover is closed.

Finally, note that outlet box hoods now must be listed and identified for “extra-duty” use. Why such a stringent requirement? Too many weatherproof covers were breaking off. Now that these must be “extra-duty” we should see far fewer broken covers.

Tamper-resistant receptacles

On a tamper-resistant receptacle, inserting an object into one side of the receptacle doesn’t open the internal tamper-resistant shutter. The only way to open it is with simultaneous pressure from a two or three pronged plug.

The 2008 NEC introduced us to the concept of tamper-resistant receptacles. It specified where you must use them, and it did that with no exceptions. The 2011 NEC added guest rooms, guest suites, and child care facilities to the list of required places. The 2011 NEC also added some exceptions, but they were applicable only to dwelling units.

But if you don’t need these receptacles some locations of dwellings, why do you need them in the same areas of nondwellings? The 2014 NEC solves the inconsistencies by combining all of the rules into one section [406.12]. Thus, the exceptions become applicable to all of the areas requiring these receptacles.

If installing receptacles in the following areas, they must be tamper-resistant:

(A) Dwelling Units. All nonlocking type 15A and 20A, 125V receptacles in the following areas of a dwelling unit [210.52] must be listed as tamper resistant.

• Wall Space—210.52(A)
• Small-Appliance Circuit—210.52(B)
• Countertop Space—210.52(C)
• Bathroom Area—210.52(D)
• Outdoors—210.52(E)
• Laundry Area—210.52(F)
• Garage and Outbuildings—210.52(G)
• Hallways—210.52(H)

(B) Hotel and Motel Guest Rooms and Guest Suites. All Nonlocking type 15A and 20A, 125V receptacles in these locations must be listed as tamper resistant.

(C) Child Care Facilities. Nonlocking type 15A and 20A, 125V receptacles in these facilities must be listed as tamper resistant. A child care facility is a building/structure or portions thereof used for educational, supervision, or personal care services for five or more children seven years in age or less [406.2].

Now, what about those exceptions? Receptacles don’t need to be tamper-resistant in these locations:

(1) Over 5½ ft above the floor.

(2) Where part of a luminaire or appliance.

(3) Within dedicated space for an appliance that in normal use isn’t easily moved from one place to another.

And nongrounding receptacles used for replacements as permitted in 406.4(D)(2)(a) don’t have to be tamper-resistant.

Dimmer-controlled receptacles

Connecting your floor lamp to a dimmer-controlled receptacle might seem like a good idea, but plugging your LED TV into the same receptacle isn’t. The average home owner may not realize this, or may not remember that a particular receptacle is controlled by a dimmer switch.

To prevent damage to connected equipment, the NEC previously didn’t allow receptacles to be connected to a dimmer switch [404.14(E)]. Now it does, but only if the receptacle and plug are nonstandard. Also, these devices must be specifically listed and identified for each such unique combination [406.15]. This way, there’s no risk of someone plugging in a piece of equipment that can become damaged.

Avoiding violations

Switches and receptacles are common types of branch circuit loads, and an electrician might install hundreds of them in a single year. As we’ve clearly seen in this article, the requirements for these have changed over the past few code cycles.

The installation methods that were OK at one time might not be OK now. Has it been a while since you’ve reviewed your designs and installation practices against Articles 404 and 406? If so, spend some time doing that review so your installations comply with the requirements of the NEC revision adopted for the jurisdiction in which you’re working.