Perhaps the most frustrating, confusing, and misunderstood aspect of any home is the wiring. If you’ve never worked with it before then just the prospect of electricity may seem scary, but a little knowledge and preparation can go a long way to help squelch those fears.
It should be noted that pretty much all electrical work in your home, besides changing a lightbulb or a smoke detector battery, should be done by a licensed electrician. But that doesn’t mean you shouldn’t know what to expect in advance. After all, the best way to avoid being taken advantage of by a contractor is by simply knowing what’s involved in their work. Since this topic can be, and has been, covered in books as thick as an oak tree, today I’ll just be talking about the ins and outs of residential electrical code.
The first thing to know about electrical code is that there is a mountain of information to absorb and it changes every three years, so no one has all of the information stored in their head (not even veteran master electricians). That’s why there are so many great resources available to help both homeowners and electricians keep track of the requirements.
The National Electrical Code (NEC) establishes the minimum safety standards that every building in the country must meet, and on top of that, each state, county or parish, and city or town all have their own standards and requirements. The NEC falls under the broader umbrella of the National Fire Protection Association (NFPA), which oversees the safety codes for a number of industries (gas, hazardous materials, etc).
An updated version of the NEC (which comes in the form of a 1,000-page book) is published every three years with new codes. The NEC isn’t a set of laws, they’re just generally agreed upon safety standards which local and state governments adopt as they see fit. So, while one town may be following the standards of 2014, another may still be working off the codes from 2005. That means if you call your electrician cousin on the other side of the country with a code question, they may give you information that’s outdated in your state.
A GFCI outlet (ground fault circuit interrupter) basically detects a difference in current between the line and load wires (which are usually supposed to be the same), so that the outlet or circuit will shut off before any real harm is done to a person or building. The practical application of this device is that it protects people from being fatally electrocuted if the outlet comes into contact with water. That’s why they are required in bathrooms, kitchens, basements, garages, exterior circuits, and anywhere else you might find water. Bathrooms and exterior circuits are also required to have at least one dedicated GFCI protected circuit (which means nothing else is on that breaker), while kitchens are required to have a minimum of two. For more information on work in bathrooms, check out this post on old house remodeling.
An AFCI (arc fault circuit interrupter) is a device that senses a break in the current and shuts off the circuit to prevent a fire due to arcing. An electrical arc, which is basically when current jumps, can reach up to 5,000 degrees Fahrenheit for residential wiring, which is enough to burn a home down in a relatively short amount of time. While GFCI protection most often comes in the form of an outlet, AFCI protection usually comes from the breaker for a circuit. The easy way to remember the difference is that GFCIs are used more to prevent electrocution while AFCIs are used more to prevent fires. According to the newest version of the NEC, AFCIs are now required in every room of the house except the bathroom. There is really no logical reason for them being required in kitchens but not bathrooms, and most electricians agree that bathrooms will probably be added in the 2017 code.
A lot of electrical codes have to do with the distance of a device to another object. For instance, there aren’t supposed to be any outlets or switches within three feet of a shower or bathtub since someone could potentially be standing in the tub while plugging something in (unlikely, I know, but they try to account for all possibilities). Another distance requirement is that no outlet can be more than twelve feet from another outlet and six feet from a doorway (which is meant to make for safer use of appliance cords), and every wall that’s more than two feet wide must have a receptacle. Hallways longer than ten feet must also have at least one outlet. Outlets installed in the floor must also be within eighteen inches of the wall. Although, in the hundreds of homes I’ve wired, I’ve never installed any floor outlets, so that’s not a very common one.
Dedicated outlets are for any specific device or appliance that require their own load. This includes electric ranges/stoves, refrigerators, dishwashers, range vent hoods, built-in microwaves, and as I mentioned before, bathroom, kitchen, and exterior GFCIs. The water heater, furnace, and A/C condenser all require dedicated circuits as well, but no outlet is required (disconnect boxes are installed instead).
Every “living space” must have at least one light or outlet controlled by a switch. The reason for the switched outlet is because you can use lamps to light the room, but generally every room needs a switch. The term “living space” is how the NEC designates bedrooms and living rooms, as opposed to a bathroom or garage. This means you can get away with having no light in certain parts of the house, but generally, everything is covered. Every interior hallway and stairwell also must have a light or switched outlet.
As I mentioned at the beginning, a lot of electrical codes have to do with where you live. For instance, in Chicago, all wiring in a home has to be run in conduit (usually with THHN rather than NM cable), but in most other places you can just run Romex through the walls. In some areas, you can use an exterior service panel (breaker box) if the weather is relatively nice year round, while in other areas exterior panels are prohibited. It all depends on your local codes.
Know the Code
If you decide to rewire your home, then make sure you brush up on your local codes. It’s also wise to hire an experienced electrician you trust, and get multiple opinions from qualified professionals. There are volumes written on this subject, and we only scratched the surface here today. We’ll be back soon with part two to answer your 10 most common questions about electrical code. In the meantime, safe wiring.