Electrical Code for Bathroom Lights: A Homeowner’s Guide

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On the surface, the electrical code for bathroom lights is no more complicated than for any living space. However, the presence of plumbing fixtures and features such as vent fans in a bathroom does create some unique circumstances. Electrical code for bathroom lights is stipulated by your local building code, which is usually based on a model national code known as the National Electrical Code (NEC). Whether you're undertaking an electrical project for the bathroom—or you just want to be prepared for a discussion with an electrician during a remodel—it's important to know and understand these important electrical codes before you begin work in the bathroom.

Understanding the Electrical Code for Bathroom Lights

The National Electrical Code is a model code published by the National Fire Protection Association, and most states use the articles from the NEC to create their own official electrical codes. Although the NEC is revised every three years (the last revision was in 2020), various states and municipalities do not always adapt the most recent edition as their own code. Make sure to consult your local code authority to determine what the actual requirements are in your area as it's possible that your community uses an older version as the basis for the local code rules. (Note that the code requirements for bathroom lighting in this article are based on NEC 2020.)

Few homeowners actually buy their own copies of the NEC, as the document is very large (more than 800 pages) and very expensive (more than $100). The key code requirements are easy to find, as many local communities make their own codes available online, and their article citations will match those used by the NEC. In addition, organizations such as the Electrical Safety Foundation International (ESFI) makes the key NEC elements available online. The ESFI offers detailed and easy-to-understand information on ground-fault circuit-interrupter and arc-fault circuit-interrupter requirements, for example, based on the exact NEC code language.

Bathroom Circuit Requirements

Like any other room in the home, a bathroom requires service from at least one branch circuit that powers lighting and sometimes other fixtures. For a bathroom, this branch circuit must power at least one ceiling light fixture controlled by a wall switch, and it may also power one or more wall sconce or vanity light fixtures. The code also allows this branch circuit to power an exhaust vent fan in the bathroom. However, according to the NEC for 2020, if the fan/light unit also powers a heat lamp, a separate 20-amp circuit must be installed to power that combination fixture.

In addition, bathrooms require service from at least one additional 20-amp circuit that powers receptacle outlets. This is similar to the requirement for kitchens, which must have two "small-appliance" receptacle circuits in addition to the general branch circuits.

Why is this required in a bathroom? Small appliances used in a bathroom are often heating units, such as curling irons or hair dryers, and these appliances can overload a general branch circuit's capacity. Therefore, a new bathroom or a bathroom undergoing major remodeling is often wired with one 15-amp general branch circuit that powers the lighting, a 20-amp circuit that supplies the outlets in the room and possibly another 20-amp circuit if the bathroom has a combination vent fan/ceiling light/heat lamp.

There is a notable exception to this "minimum of two circuits" practice: If a 20-amp circuit powers only a single bathroom and no other rooms in the house, then both the outlets and the lighting fixtures can be powered by that one circuit alone. If, however, that general branch circuit powers any other devices anywhere else in the house, then the bathroom must have additional circuits.

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Light Fixture Requirements

In addition to the required ceiling-mounted light fixture controlled by a wall switch, there may be (and often is) at least one other fixture or group of fixtures, such as wall sconces or bar lights above a vanity mirror as well as a watertight light fixture within a tub or shower enclosure. The required ceiling light fixture is often combined with a vent fan or with a vent fan/heat lamp combination. Unlike what the code allows for other rooms, a bathroom cannot be illuminated solely by a plug-in lamp connected to an outlet controlled by a wall switch. Only a ceiling fixture satisfies the code mandate due to the close proximity and frequent use of water in a bathroom.

Bathroom light fixtures (which NEC Article 410 refers to as "luminaires") that hang from cords, chains, rods or tracks cannot have any portion of the fixture fit inside a zone that is within 8 vertical feet of a bathtub or shower base rim or within 3 horizontal feet of the rim. Any light fixture that does fit within this zone must be marked "suitable for damp locations" if above a bathtub or "suitable for wet locations" if it is subject to possible water spray. Remember too that you can't place light fixture wall switches within the tub or shower enclosure unless they are already integrated into the tub or shower surround unit (Article 404.4).

Light Fixtures With Vent Fans

A light fixture that is combined with an exhaust vent fan can be powered by the general branch circuit since vent fans draw very little power. However, if this combination light fixture/vent fan is located inside the shower/tub zone (8 vertical feet from the shower or tub rim and 3 horizontal feet), then this combination unit must be rated for "moist locations" (when in the tub zone) and for "wet locations" (if subject to shower spray).

And don't forget that if this combination fixture includes a heat lamp, it should be powered by its own 20-amp circuit that is not shared by any other light fixtures or outlets.

GFCI Protection for Light Fixtures

Although ground-fault circuit-interrupter (GFCI) protection is required for outlets in bathrooms and other damp locations, the National Electrical Code does not require it for bathroom light fixtures or their wall switches. However, many bathroom light fixtures — especially those rated for damp or wet areas — have a manufacturer's requirement that the light fixtures and the switches controlling them must be GFCI-protected. If so, then it is common to install a GFCI circuit breaker to protect the entire branch circuit that powers these light fixtures.

Another means of providing GFCI protection to light fixtures that require it is to use a single dedicated 20-amp circuit to power both outlets and light fixtures and to feed power to the light fixtures through a GFCI receptacle that is wired for downstream protection. This is considered a superior method to using a GFCI circuit breaker since a GFCI outlet that trips can be easily reset right in the bathroom; you won't have to travel to the service panel to reset the breaker. GFCI circuit breakers are prone to "phantom tripping," and this can be very inconvenient for a bathroom circuit.

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AFCI Protection for Bathroom Lights

Operating in a manner similar to GFCI protection that aims to prevent shock, an arc-fault circuit-interrupter (AFCI) is designed to sense sparking (arcing) between wire contacts in a circuit and automatically shut off current flow before overheating and fire can occur. The first AFCI requirements for residential wiring appeared in 1999 when the NEC began requiring AFCI protection for sleeping spaces. In the 2020 NEC, AFCI protection is required for virtually every circuit that serves receptacles in a living space in the home.

However, the code language omitted bathrooms from the list, considering them something other than traditional living space. Thus, any circuit that is dedicated to only the lights and outlets in a bathroom does not require AFCI protection. Be aware that code requirements can change, and local rules often vary from the NEC. The general trend with each code revision has been to require AFCI protection in more locations, so it is possible that this will be required in future revisions of the NEC.

However, if the bathroom lights are powered by a circuit that also feeds outlets in another room — most often in an adjoining bedroom — then the code does require that this circuit be AFCI-protected. This protection is normally provided by an AFCI circuit breaker (or a combination GFCI/AFCI breaker, known as a CAFCI). During a bathroom remodeling project, it's important to determine which rooms each electrical circuit powers and to provide AFCI protection when needed.

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Bryan Trandem is an avid home improvement DIYer and trained Master Gardener. He has been writing and editing books and articles on gardening, home improvement, woodworking, and home decor for more than 30 years. He lives in Minneapolis, MN.

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