National Electrical Code Top Ten Tips: Article 422 -- Appliances
by Mark Lamendola
Based on the 2020 NEC
Please note, we do quote from copyrighted material. While the NFPA
does allow such quotes, it does so only for the purposes of education
regarding the National Electrical Code. This article is not a substitute
for the NEC.
These are the 10 NEC Article 422 items we deem most important, based
on the pervasiveness of confusion and the potential costs of same.
- An "appliance" has a specific definition, which you will find in
- Some appliances have a protective device rating on them. This is
not telling you how much current the appliance draws. It is telling
you the maximum breaker size for the circuit that supplies the
appliance. You can't exceed this [422.11(A)].
- If there is no breaker marking on the appliance, a maximum may
still apply. Several types of appliances have maximums, as denoted
in 422.11(B) through (G). If that reference still doesn't tell you the maximum, search for it online for that specific appliance and/or contact the manufacturer.
- Central heating equipment, per Article 100, is also a type of
appliance. Any such equipment other than fixed space heating
equipment must be on its own branch circuit. There are a couple of
exceptions, but those essentially allow for very closely related
equipment. This was formerly mentioned in 422.12, but that section was been removed with the 2020 revision.
- When you are calculating total loads, consider the typical
residential water heater to be a continuous load [422.13]. That's because the rule applies to storage type water heaters with a capacity of 120 gallons or less. A larger water heater will likely cycle off for enough time that considering it to be a continuous load would be erroneous.
- The flexible cords of garbage disposals, dishwashers, trash
compactors, cooking units (wall-mounted or counter-mounted), and
range hoods have specific requirements [422.16(B)]. In residential construction and retrofit, these requirements are often not met. If servicing, for example, a dishwasher, show the homeowner or landlord what is wrong with the electrical cord and the water supply line, and offer to replaec both of them. This is not only a nice way to get an upsell, it's a nice way of ensuring your customer you are looking out for their best interests.
- If you do any work in a room that has a DIY-installed ceiling
fan, beware! DIY people are notorious for code violations, and this
is one place they are likely to make them. One common problem is
improper mounting. The fan must be supported independently of a
standard outlet box, or it must be supported by a box identified for
the purpose and installed per 314.27(D) [422.18].
- A less common violation involves the disconnecting means for the garage
door opener. The opener is an appliance, and the motor is typically
1/2 hp. But any appliance with a motor more than 1/8 hp cannot use
the panel breaker as the disconnecting means [422.31]. That's one reason these are typically designed to be plug and cord powered. Skipping the receptacle and hard-wiring in the opener would violate this rule. Even if the opener is only 1/8 hp, install a local disconnect to avoid the inconvenience of having the disconnect remote from the opener.
- Switches or circuit breakers used as a disconnecting means must
be of the indicating type [422.35]. That just means they must be marked "On" and "Off". Ensure you mount them in the correct orientation. If the switch operates vertically, then the handle should be up when in the On position and down when in the Off position.
- When you install an appliance, ensure its nameplate remains either visible or easily accessible [422.60]. In most cases, this is nothing to worry about because the appliance can easily be slid or rolled from its installed postion to one that provides nameplate access. In some cases, the appliance cannot be easily moved so the nameplate is easily accessible only if you orient the appliance to face a particular way thus exposing the nameplate.
If you can't orient the appliance so the nameplate is exposed, then you'll need to devise a means of allowing it to be easily moved.
For example, the particular dishwasher you're installing has its nameplate on the back and the unit is an undercounter unit. In this case, you will need to ensure the electrical cable, water supply hose, and drain hose are all of sufficient length to roll the dishwasher out far enough for the nameplate to be read. You'll also have to ensure those hoses and that cable are safe when the unit is rolled back in. So use hoses with steel-braided coverings and run each with a single loop that can expand and contract with movement. Use the loop method with the electrical cable, as well. Route these carefully.
For example, you are installing a refrigerator. And it's heavy. The floor is linoleum and the wheels bite down into it. To solve this problem, pull the refrigerator out from where it goes. Clean and dry the floor, then put down a desk chair mat. This is plastic sheet that is thin enough not to be obtrusive but thick enough to be stable under that weight. You can easily roll the refrigerator in and out. Usually, you do not have to cut these to fit because they are almost exactly the needed size. You probably should not put this under the range, but you can set the range down on a sheet of linoleum cut to fit from the "left over" roll.