3/11

Electrical Panel Locations

Question: Can an electrical panel be installed in a bathroom?

Answer: Do not install an electrical panel in a bathroom.

All electrical conductors, equipment, light fixtures and so on must be identified for use in the operating environment in which they will be installed (indoor dry locations, indoor or outdoor wet locations, hazardous [explosive] location inside a vehicle paint spray booth, etc.). There is a basic rule in the code that says unless otherwise approved and marked accordingly, no electrical conductors or equipment are permitted to be installed in damp or wet locations, locations exposed to gases, fumes, vapors, liquids, other deteriorating agents, or locations exposed to excessive temperatures.

Electrical conductors and equipment that are rated for dry, indoor locations free of any corrosive effects obviously would be the most economical to purchase. Do they make equipment for corrosive locations, such as inside your favorite drive-through car wash? Yes, but it’s going to be much more expensive. It’s always best to plan and layout every installation in such a way that the electrical equipment is located where it is protected and kept dry, and then minimize the quantity of electrical wiring that is extended into the less desirable locations.

4/11

Which Panels are Approved for Double-Lugging?

Question: How do you determine which electrical service panels are approved for terminating two neutrals together under one screw terminal, or one neutral and one equipment grounding conductor under one screw terminal, often referred to as “double-lugging”?

Answer: As they say, the devil is in the details.

First of all, neutral conductors can never be doubled-up under one terminal; the code has specifically prohibited this practice since 2002. For other terminations, the electrical code has a very basic rule; terminals for more than one conductor must be identified. Space is limited on terminals due to their small size; it’s more important for that precious real estate on a terminal to be marked with the size of conductors, whether it’s approved for copper or aluminum, the temperature rating, etc.

There’s not much room left for identifying whether or not the terminal is approved for more than one conductor. Often you have to look at the terminal or circuit breaker packaging, product wiring diagrams, the manufacturer’s label inside the electrical panel, a product specification sheet from the terminal or circuit breaker manufacturer, online at the manufacturer’s website, etc. It inevitably requires some detective work unless the electrical panel or packaging is clearly marked, and different brands of terminals and circuit breakers have different allowances.

When in doubt, don’t “double-lug” two conductors under a single terminal. It’s a favorite violation that gets flagged by private home inspectors when homes are being bought and sold.

5/11

Labeling Circuit Breakers

Question: Does the electrical code require that electrical panel circuit breakers be labeled?

Answer: Absolutely.

There is no gray area here. Labeling a new electrical panel only takes a few minutes. Tracing circuits and labeling an existing panel is a task that is best done with two people and could take hours. A complete directory helps to ensure the safe operation of the electrical system, especially in an emergency. The code requires that every circuit and circuit modification be legibly identified as to its clear, evident and specific purpose or use. The identification must be included in a circuit directory that is located on the face or inside of the panel door. The circuit directory must be durable enough to withstand the environment in which it is located.

Each label identification must contain a degree of detail that distinguishes it from all other circuits. Even spare, unused circuit breakers must be identified. And don’t create personal labels such as “Mary’s Bedroom” that will have no meaning to the next family that owns the home.