ELECTRICAL DESIGN


Safety First Electrical

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Electrical Design. Basic guidance on planning residential wiring for safety, functionality, and National Electrical Code compliance. ©2001 David Eli Shapiro

Disclaimer

None of the information you will read is intended as legal advice. None of it is sufficient in itself to serve as a "how-to" to let you do your own wiring. None of it is intended to substitute for the Terms of Engagement under which I work as a contractor or consultant.

For comfortable reading:

You are welcome to read the material below on line. However, it is formatted more like a text document; you may be more comfortable printing it out.

Contents

I start with an explanation of the plans that are needed before starting a sizable electrical project.
I then talk about the legal requirements for various aspects of your electrical system, including rationales and options.
From that, I lead into a discussion of lighting and controls.
Next, I introduce some information on smoke alarms that you may not know.
Finally, there are four appendices:

  • GFCIs;
  • Labeling
  • The elderly and disabled;
  • and
  • Children.

    Plans

    On any sizeable job, involving the installation of more than ten electrical devices, the first thing you need is a set of plans. You can prepare them, provided you understand the basic symbols used for electrical equipment. Sometimes, I am paid to sketch them. Other times, an architect, professional drafter, or general contractor will do so for you. The plans do not need to be professionally perfect, but must include everything an architect would show. This includes the following: fairly accurate scaled dimensions; doors (including closet doors) and their directions of opening; other permanent installations along walls, such as kitchen counters, bathtubs and fireplaces; all electric utilization equipment that will be permanently connected, or fixed in place such as baseboard heaters, smoke alarms, furnaces, doorbell transformers and garbage disposals; and electrical panels, telephone jacks, intercom, alarm and doorbell stations, switches, receptacles, fans and lights, stove, dryers, washing machines, and dishwashers.

    The National Electrical Contractors Association will sell you a nationally-recognized standard that offers you pictures and schematics to guide you in drawing up your plans. Please remember to include items such as range hoods, central air conditioners, attic exhaust fans, thermostats, under-cabinet lights and garbage disposals. Low voltage systems often require a local source of power. When this is a permanent connection, it must be approved by the electrical inspector -- so it has to be on the electrical permit. Not integrating the power and low-voltage plans can lead to problems.

    Code requirements

    Any remodeling, renovation, new building, or conversion of a non-habitable area to living space must meet current Code. I am responsible for ensuring that my installation meets the 2011 or 2014 or 2017 National Electrical Code (depending on jurisdiction) and applicable local variations. (On later jobs this will be the 2020, etc. Code.) In preparing for my visit, you need to determine what lights and switches and receptacles you want, with the Code as a minimum guide. I will review and modify your plans as necessary. While Chapter 2 of the Code, particularly Articles 200, 210 and 220, is your best guide, I will mention some considerations you must keep in mind.

    You can read the coded online, free and legally, at www.nfpa.org/70, provided you sign a pretty-normal agreement.

    RECEPTACLES

    Rationale

    There have been many accidents and fires over the years because of electric cords stretching on, through or under places they did not belong. Extension cords, some are surprised to learn, are designed for temporary use only. This also is true of power strips, such as sometimes are mounted to the backs of desks. The tragedies that stemmed from ignoring this have resulted in legal rules that attempt to provide enough receptacle outlets so that extension cords should be unnecessary. Installations that follow the Code should minimize the use of octopus adapters. The point is to space receptacles close enough that wherever you plug in an electrical appliance there will be a receptacle within reach without your exposing the appliance cord to hazard.

    Requirement

    The rule is explicit. Everywhere in habitable rooms, not counting closets, pantries, bathrooms, unfinished (having exposed joists and studs) basements and attics, garages, and hallways, every point along the wall shall be within 6' of a receptacle, measured along the wall without crossing doors, fireplaces or other hazards. Broken lengths of wall shorter than two feet do not require receptacles, but even a 30" section behind a door does count. One reason is that the door could later be rehinged on the other side or removed, and a floor lamp set in that 30" space. Thus the greatest distance permissible between receptacles along an unbroken wall is 12'. Just about every hallway also needs at least one receptacle.

    Bathrooms require at least one receptacle, near the sink. (These must be on 20 amp circuits that don't serve non-bathroom spaces.) Finished attics and basements are treated like other habitable spaces. Each separate unfinished area of a basement requires at least one. At least one is required on the outside of the building, accessible from ground level. Most porches and unfinished attics may not require receptacles if no electrical equipment is located there, but it is worth installing some anyway. Kitchens require additional receptacles above counter tops. Here, an unbroken space 1' or wider requires power, and the maximum spacing is not 12 feet but 4 feet. Kitchen receptacles must be served by at least two 20 amp circuits that serve only receptacle loads, and both must be located in each counter. These two or more circuits can serve receptacles only in food-preparation areas--kitches, dining rooms, and pantries. Sinks and ranges are considered breaks; you do not want to drape cords across them. You are welcome, and often wise, to install more convenience receptacles than the minimum required ones. All kitchen counter, bathroom, garage and outdoor receptacles require ground fault circuit interrupter (GFCI) protection, as do receptacles in unfinished basements and basement crawlspaces. See the Appendix on GFCIs.

    LIGHTS

    Rationale

    Plugging in lamps and using their switches for light is not considered a safe way to find your way through a house. Generally, groping for pull chains is not considered safe, either.

    Requirements

    Kitchens, bathrooms, hallways and stairs (indoors and out) require switch-controlled lights mounted on the wall or ceiling. Inside stairs should have a switch at each landing to control the stairway light or lights. Other habitable rooms are permitted to have switch-controlled receptacle outlets instead of permanently-installed light fixtures. A paddle fan whose light may be turned off by a pull chain or a portable remote control can be but really should not be substituted for the required switch-controlled light, as the wall switch may be bypassed by the other control.

    Closets

    There are special restrictions on lighting in clothes closets. Because of the danger of leaving a light burning and thus accidentally setting combustibles on fire, clothes closets require a storage-free area around light fixtures, an area that extends floor to ceiling. No shelves may protrude in this area, and hanger bars must be mounted such that no part of garments on them will protrude into it. Only certain types of fixtures may be installed in these closets, even with the restrictions. They don't apply to storage closets without clothes bars, under the usual interpretation.

    The empty area specified is pictured in the Code book; I'm not going to reproduce the sketch here. Some shallow closets must be lit by fixtures located on the ceiling outside, shining in. Mostly, the closets that can legally accommodate lights are walk-ins

    CIRCUITING

    After the basic plans are prepared, I will determine, in consultation with you, how the wiring is to be run and protected. This both determines and depends upon the size of your electric service. Several Code rules apply. In addition, your life, and that of anyone dealing with your wiring in the future, will be a whole lot easier if we rationalize your wiring. By this I mean that we separate the circuiting enough that it is easy to accurately label your panel, hard to get confused over what circuit controls what electrical device, and hard to overload a circuit or to create interference between circuits.

    FIXTURES AND OPTIONS

    You need to think about fixtures fairly early, because they affect wiring and circuiting choices. For example, both the location and the outlet box used to support a normal light fixture are inadequate for a ceiling fan or a heavy chandelier. Except for some special arrangements, ceiling outlets designed to serve one light from a wall switch will not let you use separate switches on the wall for an exhaust fan, a heater and a light, or a paddle fan and its light kit, without rewiring or, perhaps, using wireless controls.

    There are three criteria to keep in mind regarding light fixtures and fans. First, are they suitable for the locations where you intend using them? They need to be marked "suitable for wet/damp location" if they are to be used in such spaces. ("Damp" includes screened porches, some bathroom areas, and most under-house crawlspaces.) They need to be marked "Thermally protected" (or TP) or "Intrinsically safe" (or IC) (or IC) if they are to be used recessed in a cement ceiling or thermal insulation. Recessed fixtures also require clearance from combustible materials inside the ceiling--such as joists and subfloors. Fans for cathedral ceilings need to have a swivel hanging arrangement to allow them to hang plumb. Fixtures also need to physically fit in the space where they will be installed. This can be a problem when fixtures are located near walls or recessed in shallow ceilings or in roof spaces near eaves. Paddle fans need to have their blades--not just their housing canopies--at least 7' off the floor. Lights can extend lower, if nobody real tall is likely to walk under them.

    Second, will your fixtures do what you want? A paddle fan will not move air from one room to another. One with 24" blades will not provide any turbulence 10' away. One light fixture probably will not give adequate reading light in a large room. A fixture that requires small reflector bulbs, say "R-20"s, will be much more expensive to relamp than one that takes normal light bulbs; on the other hand, a spotlight effect may be just what you seek.

    Third, will the fixtures work with your wiring? An outside light designed to fit against the house will not mount against a weatherproof box protruding from the surface. Similarly, a fixture designed for installation against the underside of a ceiling probably can't be installed legally against a surface-mounted electrical box. A fixture marked, "Use only with 75 (or 90) degree C wiring" cannot be installed in any house more than a very few years old without rewiring. (Prior to 1987 or 1988, normal cables installed in houses contained conductors with insulation only suitable for fixtures that generated 60 degrees C or less.) Look very carefully for such markings, before buying fixtures for use with older wiring.

    Controls

    You should consider control systems when choosing fixtures. Only a small subset of outdoor lights will accommodate photocells or motion sensors. Dimmers, timers, and remote controls can be great conveniences, and usually can replace plain wall switches at any time. (Most fluorescent fixtures, though, cannot be dimmed.) As mentioned, a wall switch intended for a light will not conveniently adapt to separately control a paddle fan and the associated light fixture, with some exceptions. Plan ahead, and appropriate wiring can be run to allow separate controls. Similarly, installing a switch at each entrance to a room initially is much less expensive than adding a second switch later on. Should all lights go on together? Should they go on in banks? Too many switches can be confusing, so these decisions involve tradeoffs. I've sometimes found it helpful, and aesthetically acceptable, to label switchplates.

    Light locations

    Once you decide, through observation of existing installations, on the types of light fixtures you wish installed, I recommend that you experiment. If you are renovating an existing house, I suggest using clamp-on or other relocatable lights at proposed locations. If you are thinking about recessed lights, you will want to poke (inconspicuous) holes in the ceiling to check that there is empty space above the locations you have chosen.

    Light brightness, color and quality

    How bright should your light be? So long as it doesn't glare, the more light during the day, the better. It can be better for spirit, for energy, and for navigation. One way the Johns Hopkins School of Nursing CAPABLE study helped elderly people avoid unnecessary hospitalizations is by giving them enough light that they wouldn't trip and fall as often. An incandescent 60 watt light bulb produces perhaps 800 lumens. If you buy LEDs, look at how many lumens they claim to put out, not what incandescent they claim to be equivalent to. I've seen purported "60 Watt equivalent" LEDs that put out less than 700 lumens.

    Light color matters. We need to see by bluer light during the day if we want to sleep well at night. We want warmer colors at night, though, or the light will keep us up. A warm color temperature is 2000 to 3000. A cooler, bluer, color temperature is 4000 or 5000. (The numbers are the degrees you'd have to heat maybe a piece of steel before it glowed that color--red hot versus white hot and so forth.)

    How well we see the colors of objects depends on the color of light illuminating them. A cheap LED flashlight will shine a restricted range of blue light, and you'll get weird-looking color photos by that light. The way experts classify light quality is changing, because a simple number is trying to account for a range of wavelengths. However, you don't need those details. Look for Color Rendering Index, CRI, of at least 80 or 90, if you want to see colors well. In my attic crawlspace, that's irrelevant, so I didn't even look up the fixtures' color temperatures or CRIs.

    SMOKE ALARMS

    These are critical. Gluing in place or plugging in the odd standalone smoke alarm does not protect your family properly, for a whole host of reasons. Some are straightforward, others are subtle, most-easily understood by someone with a suitable background, or at least a very good head for technical details. All of those required--and these include some in locations that may not be immediately obvious--should go off simultaneously, and each one should be connected to two sources of power, unless it runs on a permanent, 10-year sealed battery. All should be replaced at least every 10 years; their reliability falls off considerably after that point.

    There's a raft of additional material to learn about them before designing an installation. A goodly bit can be found on manufacturers' web sites.
    For an intelligent homeowner's report, I invite you to visit Tom Metcalf's site, http://metcaffeination.net/weblog/2009/06/07/confounded-smoke-alarms/
    If you want to go directly to more-technical research material, you can visit NIST's site, at http://smokealarm.nist.gov (Tom Metcalf links to it on his blog, which I just referenced).
    By 2020, a new standard will be in place for smoke alarms, and much more sophisticated ones will be available. Don't wait for it, though, if you're under-alarmed.

    DELVING YET FURTHER

    There are four appendices, half of which go into detail regarding special circumstances that might cause you to modify your wiring design. Before you go there, I want to touch briefly on two issues that didn't quite fit anywhere else above. The first is special needs and interests, including future-proofing.

    The minimum-quality new phone line that complies with FCC rules, as of 2001, is called Category 3. There is no particular requirement that you install any phone or data jacks, though, nor that you locate them anywhere in particular. Experts do recommend, though, that you locate jacks on at least two walls of every habitable room.

    If you do install jacks, you face choices that involve trade-offs between cost and quality. It is cheaper to run Category 3 line, stapled along baseboards, than the alternatives. Radial wiring, which runs a separate line to each room from a central box where a phone jack might be desired, is a much better job, and there are now Category 5, 5e, and 6 protocols, and even more. One customer had me run flexible conduit from a central location to various rooms, with drag lines in it, so that whatever the latest and hottest phone line in the future, if they want to run it, we simply can tie it to the line and drag it through the conduit leading to the room where they want the jack. Think about your likely needs. The most efficient time to do such other work is when walls are opened for your power wiring.

    If you are using your lines for more than just chatting, you might want to consider how to minimize interference. Telecom professionals advise keeping phone lines at least half a foot from power lines, and where they do cross, crossing at as close to 90 degrees as possible. They also recommend keeping phone or telecom jacks well away from power outlets such as receptacles--not even attaching them to opposite sides of the same stud.

    Another issue has to do with choosing receptacles. The NEC rules are satisfied by the installation of single, not even duplex, receptacles at the specified spacings. That's mostly a silly idea though, as single receptacles are more expensive than standard duplex receptacles. There are other odd possibilities, though, that might merit your consideration. Would black, or brown, or red receptacles fit your color scheme? They're available for a price, and will serve better than will regular ones with a coat of paint. Do you want extra-heavy-duty ones, or at least receptacles with nylon rather than thermoplastic bodies? "Spec grade" can mean anything or nothing, but "Fed Spec" has specific durability requirements. Do you want receptacles with surge protection built in? Will you need to plug in more than two items at a certain location, so a quad receptacle, or even a box with three or four duplex receptacles, will make sense? The difference in my labor required for one of these variations generally is trivial.

    The last miscellaneous item that I will bring up here is the Arcing Fault Circuit Interrupter (AFCI). This is a no-longer-new type of protective device, available only in circuit breaker form, that is required for all new circuits serving sleeping areas. Its purpose is enhanced fire protection, and while a legal requirement it does not yet have whole-hearted industry support, especially among handymen and builders. Like the GFCI, and for identical technical reasons, it cannot be used on some circuits that have messed-up wiring without that hazard being sensed, causing the AFCI to trip. It can, and legally must, be used on new circuits feeding anything in a bedroom under some versions of the Code; nearly all new residential branch circuits under the very latest rules. With the new circuits properly installed, it should not have any problems. Its use to protect older circuits is even more important; with them, though, it may well trip and stay tripped, not allowing power through, until sometimes-unsuspected problems have been corrected. It also will trip if you plug in a tool that is having problems, or juzst is very electrically "noisy." There are fewer and fewer of the latter.

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    APPENDICES:
    1 GFCIs
    2 LABELING
    3 THE ELDERLY OR DISABLED
    4 CHILDREN

    Appendix 1: GFCIs

    Definition

    GFCI is the initialism for Ground Fault Circuit Interrupter. It is a device to protect you from electric shock and electrocution.

    Varieties

    There are two common permanently installed versions of the GFCI: the circuit breaker and the receptacle outlet. (There is a switch version as well, but it is relatively uncommon.) The circuit breaker GFCI is installed in your electrical panel and has a switch handle looking just like your other (full size) circuit breaker handles. When it trips, the handle moves, and needs to be reset just like those of other breakers. However, it also has a TEST button, next to the handle. The receptacle GFCI lives in an outlet box and, just like an ordinary receptacle, has openings for the three prongs of one or two attachment cord plugs. It also has a test button, and in addition it has a reset button, because unlike the circuit breaker it has no switch handle. Most receptacle GFCIs are a smooth rectangular faced ("decora") design, and come with a special cover plate. For temporary use, one can also purchase plug-in or extension cord versions of the GFCI.

    Operation, and comparison with overcurrent devices--fuses and standard circuit breakers

    A fuse or circuit breaker is designed to protect your appliances and house from overcurrent. Too heavy a load can cause a fire because wires overheat. Overcurrent also can indicate that a particular appliance is shorted out (damaged), greatly overloaded or stalled. GFCIs, on the other hand, are designed to protect your life from electrical leakage that could take a path through your body. Instead of tripping in response to overcurrent, they operate when they detect that some current has escaped from a circuit's wiring. GFCI circuit breakers combine both functions.

    Legal Requirement

    A house that was wired twenty, fifty or a hundred years ago is grandfathered--not required to have GFCIs--until work is needed on those parts of the wiring to which GFCI requirements now apply. This requirement comes into place even when you simply replace a receptacle.

    GFCI protection is required where people are considered especially vulnerable to electrocution. Generally, increased danger of electrocution is found at the intersection of wet people and electrical appliances. For going on three decades, the National Electrical Code has required home GFCI protection in bathroom and outdoor receptacles or at functionally outdoor receptacles, such as those in garages and ground level screen porches and decks. The 1987 Code added a requirement for GFCI protection of countertop receptacles near your kitchen sink, and of at least one basement receptacle. In 1990, all receptacles in unfinished basements were covered by the requirement. Kitchen countertop receptacles, plus those near wet sinks, nowadays are covered as well. Swimming pools, garages, whirlpools, construction jobs, and fountains also have GFCI requirements.

    Additional GFCIs

    GFCIs can serve an additional purpose in some homes. Old, ungrounded systems are not safe to use with modern, three-prong appliances. In fact, three prong appliances normally offer a greater likelihood of shock, if they malfunction when not grounded, than do two prong appliances. GFCIs provide fairly adequate safety to allow the use of three prong appliances in ungrounded systems.

    Until this was determined, people with very old or very badly wired houses with ungrounded circuits had three choices. First and best, they could have an electrician replace their cables or add ground wires, which takes considerable time and money. Second, they could make do with two-prong appliances exclusively. Third, they could take their lives in their hands: breaking off third prongs, using three prong adapters, using two wire extension cords, or simply installing three prong receptacles where they didn't belong. None of these tricks provides a jot of safety if the system is not grounded. With a GFCI, this can all be made pretty safe.

    By now, GFCIs may sound so good that you may wonder why not give all circuits GFCI protection, perhaps the way they do in England. Unfortunately, some mixed-up wiring simply will not permit a GFCI to function. If you're lucky, an experienced electrician will recognized this on examining the wires, or will find this out as soon as the GFCI is connected the the circuit is turned back on. Other times luck runs against you.

    Safety-minded people do add GFCI protection to additional circuits. For example, a GFCI offers far better protection than do most childproofing designs. The only way an infant can be killed by a correctly functioning GFCI receptacle is by simultaneously sticking objects in two parallel slots.

    GFCI use is limited for two reasons. The first is expense: GFCIs cost far more than normal circuit breakers or receptacles. The second is nuisance tripping, which I discuss further below.

    Installation Options

    If you are adding a GFCI, should it be a receptacle or a circuit breaker? They offer similar protection, and either one can protect multiple outlets. Generally, the circuit breaker is preferable for protecting multiple outlets, where a circuit breaker GFCI can be used. Whatever receptacle goes dead, you still will be able to go to the panel and check breakers. With receptacle GFCIs, if for example your bathroom receptacle goes dead you may forget that it is protected by the GFCI receptacle on the outside of the house. A possibility intermediate between the two basic options is to install a receptacle GFCI in your basement adjacent to your panel, and run power from there up to other outlets. This can solve the problem of how to install GFCI protection when you have a fuse box rather than circuit breakers. (Note that this option is not legal for a kitchen receptacle circuit, because it may not have outlets anywhere but in the kitchen and related food preparation areas.)

    In a new home, it is absurd to use GFCI receptacles rather than GFCI circuit breakers, unless your budget is terribly tight. The discussion below focuses on rewiring and renovations.

    Bathrooms

    Perhaps half the time, a receptacle outlet can be added at the bathroom wall switch location, with little damage to the wall. This depends on the wiring layout. If the vanity fixture contains a receptacle, that must have GFCI protection or be disabled. In some wiring layouts, a GFCI switch will protect the vanity outlet, eliminating your need to install a separate GFCI receptacle. When suitable power is not available at the switch, it sometimes is easiest to run power for a GFCI from outside the bathroom -- whether from the basement GFCI or just from a normal outlet on the other side of the wall. The switch or the circuit breaker option allows you to avoid chopping tile, as might be necessary to install a separate GFCI receptacle. A separate issue is that bathroom receptacles are now supposed to be independent of circuits serving other areas. This may, however, only be deemed to apply to new construction. We have to consult with your local inspector.

    There are three arguments against installing a GFCI circuit breaker. First, it is considerably more expensive than a GFCI receptacle. Second, there is the danger of nuisance tripping. If you replace a regular circuit breaker that serves many outlets with a GFCI breaker, a leakage problem at any of the outlets will kill power to all of them. It may not be advisable, for example, to have your refrigerator on such a circuit, and one home inspector with whom I've discussed this vehemently objects to installing them on circuits serving gas stoves with electronic ignition. While the oven will not release gas if you turn it on after power is cut off, the range top may. Some very old fluorescent fixtures, and some power supplies for outdated electronic equipment will in normal operation trip GFCIs. The third problem with GFCI circuit breakers is that one particular wiring design called the multiwire circuit fools a single GFCI into thinking there has been leakage. An electrician can determine whether any particular circuit is part of a multiwire circuit, at least a legally-installed one. (Sometimes ignorant work can create an illegal multiwire circuit, which can be both dangerous and hard to identify or correct.). With some multiwire circuits, your best bet is to put in receptacle GFCIs; with others, you can use special two-pole GFCI circuit breakers. Some prefer to avoid GFCIs for computer circuits, preferring the risk of electric shock to the risk of disk crashes.

    Afterthoughts

    Being complicated devices, GFCIs have a slightly higher defect rate than, say, switches. Test them, at least initially if not monthly as instructed. New ones now are required to self-test. Both kinds of GFCIs can also be installed wrong, and consequently not protect anything; this usually will trip them, though.

    Appendix 2: LABELING

    To label your panel, new or existing, it is best to have a partner to help reduce the running around; however, that is not essential. First, make sure you can read the numbers associated with each circuit breaker or fuse. If necessary, touch up the markings that should be embossed on your panel. Next, prepare plans showing where everything electrical is located. Move furniture and storage boxes, so you don't miss any outlets. Then test to make sure all electrical outlets and devices work. Test by turning on lights, operating appliances and plugging in a working lamp or radio to receptacles. Turn thermostats up or down as appropriate to trigger heater or air conditioner operation.

    Once everything is marked on your plans and confirmed as working, unscrew one fuse or flip one circuit breaker. Go through the house and test everything again. Now mark the number of that circuit on the plans alongside each item it controlled. Do not neglect furnaces, air conditioners, attic fans, doorbells, alarm systems, and outside receptacles. Then restore that circuit (and make sure it's back on) and proceed to the next. If a circuit seems to have no function, leave it off. Sooner or later you will learn what it controls, if only by the smell of rotting food from the downstairs freezer. If two fuses or breakers both seem to control an item, there are three main possibilities. Either one of them is a main or service switch, which offers backup protection for many branch circuits, or something is seriously miswired. Alternately, the item may require 240 volt or 208 volt power, which takes a double-width circuit breaker or paired fuses. They really should function together rather than being capable of independent flipping.

    Mark on the plans the locations of any subpanels, and label the subpanels. Mark which fuse or breaker in the main panel feeds which subpanel. If you are unable to determine what circuit controls a load, turn everything off at once and see if that kills it. If you are unable to determine what load a circuit feeds, leave that circuit off, and sooner or later you will find out (unless it is a spare). "Finding out" can mean, as mentioned, discovering that the food in the basement freezer has started to rot, because it's the one thing you forgot to check. That's still better than not knowing how to disconnect the freezer in an emergency without killing all power to the house.

    Appendix 3: The Physically Impaired or Elderly

    Children, invalids, and some elderly can benefit from judicious planning of electrical systems. Children are treated separately, below, but some of this section is also applicable to them.

    Elderly and handicapped

    The needs of the elderly do not differ in kind but rather in degree from those of younger people and those of invalids. Reduced agility may suggest installing more convenient controls. This can mean added switch locations to reduce walking, sound activated switches operated by a finger snap or hand clap, automatic switches on timers or motion sensors, bluetooth or centralized master controls to eliminate unnecessary walking. Feelings of vulnerability, to intruders or to medical emergencies, can be addressed with security systems, such as additional perimeter lighting, alarm systems, intercoms, extra telephone jacks, panic buttons, hotlines and closed circuit entrance monitors.

    Making switches and receptacles easily accessible can mean lowering switches in children's rooms or rooms for wheelchair users, and raising receptacles (to at least 18" above the floor; 40 or 48" may be even better) for flexibility-impaired people. Wheelchair users optimally have unencumbered routes 36" wide, except at doorways. Items such as wall sconses should not protrude into passageways more than 4" between 27" and 80" above the floor. This is not only to avoid hindering wheelchair travel: blind persons' canes may not alert them to protrusions above 27" or so. Kitchens and bathrooms not designed for accommodation can be particularly challenging for wheelchair users. To be reached reliably from a wheelchair, a switch or plug to the side can be from 9" to 54" above the floor, but if the unobstructed reach is forward, this shrinks to between 15" and 48" above the floor.

    Sensory deficits can be compensated for through design options. For people with significant hearing loss, telephones, doorbells and alarm systems such as smoke detectors can operate bells or sirens of almost any loudness. There are auxiliary devices that will produce a much lower-frequency signal than standard smoke alarms. These are required by law where an occupant has a hearing deficiency.Those with more profound hearing loss can substitute stroboscopic lights -- bright enough to wake someone from sound sleep -- for auditory signals.

    People with visual loss often require brighter--but glare-free--lighting for reading and household tasks. Halls, walks and stairs can pose the risk of a fractured hip to a feeble person attempting to navigate by a 40 watt bulb 15 feet away.

    One problem for feeble people is forcing plugs into new, tight receptacles. With use, receptacles eventually lose all spring tension. They are then dangerous, because they do not make good electrical contact with the prongs of inserted plugs. One answer is to use listed adapters until a receptacle's grip relaxes. Hospital grade plugs may be designed better for this purpose, as well as being more robust.

    Another problem, not unique to the elderly, is that if the instructions on a device are too complicated, it may be useless. This holds for systems as diverse as lighting controls, security devices and telephones or intercoms.

    Appendix 4: Children

    There are three aspects to designing electrical systems for children's environments. First, children need to be protected from electricity. Second, electricity needs to be made safely accessible to their needs. (These ends may seem contradictory.) Third, electrical system design can ease your job of taking care of children.

    Protecting children from electricity

    Children have a tendency to get into things. They may stick objects into receptacles, chew on cords, drop electric appliances in water and poke into lampholders when the bulb is out. Since electricity can kill, and a number of children are electrocuted each year, the safest solution is to never allow them access to electricity unmonitored. This may not be realistic. In an older house, it may be impossible.

    Let's consider some of your choices. First, all outlets in a nursery, children's room or playroom can be on a separate circuit breaker which is shut off at night, or, better, whenever there isn't an adult monitoring them. Night lights can be battery operated. This certainly is extreme, but it is possible to do when newly wiring or rewiring. Putting all the receptacles in the room, but not the lights, on a separate circuit would accomplish nearly as much.

    Second, the receptacles as well as the lights can be all switch controlled. That switch can be made inaccessible by elevation beyond their reach, by locating it in your room, or by using a key-operated switch. Elevation has the disadvantage of inviting children to climb for access. A key-operated switch has the disadvantage of inviting the children to poke objects in the slot in an attempt to operate the switch. All three systems will be quite a nuisance when the room's use changes, and certainly will not help resale value. More important, the latter two systems could impede egress lighting in the event of an emergency. It is possible that an electrical inspector would not approve some of them as not meeting the intent of the requirement for switched lights.

    Third, Tamper Resistant receptacles are inaccessible to probing objects, and are now required in areas where children might be left. However, as I explain below, any time a device is plugged in to a receptacle, it may allow a small explorer to encounter electricity, even if the device is turned off.

    Fourth, you can use ground fault circuit protection. This choice leaves electric power available but renders it close to safe. Ground fault interrupters (GFCIs) are not calibrated to protect children, but they do as much as anything can to eliminate the danger from the most common way children get shocked.

    Making receptacles inaccessible is certainly the most common system employed. Installing receptacles four feet up on a wall does keep them out of easy access range for toddlers.

    Of course, the child still can get hurt by intercepting electricity from an appliance that is plugged in, for instance by chewing on the cord. My former dentist mentioned off- handedly that the most common mouth reconstruction he performs is for children who have done just that. The solution is two-fold. First, monitor children until they can be taught to respect electricity. Second, route cords behind heavy furniture (NOT under furniture or rugs where the cords can be damaged and start a fire, and NOT pinched between furniture and wall) so that children have little access.

    Making electricity accessible to children

    Empowering somewhat older children to use electricity has two aspects. The first is educational, and that topic goes beyond the scope of this treatment. The second is basically putting things where children can reach them. I recommend that switches be accessible to children without climbing; there are extenders that can be attached to switches, if you prefer to install switches at more standard mounting heights. The same is true of receptacles. If children are authorized to use kitchen appliances, there should be alternatives to their precariously clambering up to reach counter top receptacles.

    I do not recommend teaching young children to change light bulbs or fuses. However, it is unwise and probably illegal to keep your fuses or circuit breakers out of children's way by making them fully inaccessible. Putting the panel behind a door that a small child cannot operate may not be a bad idea.

    Surviving child care: electrical design

    There are certain design choices that can make child care easier. The first involve communications. Consider the impact of children on your need for convenience outlets and circuiting. Laundromats, for instance, become a distinctly less attractive choice when the amount of laundry doubles. Octopus adapters and extension cords should become things of the past, given the increase in fire risk they create.