Electric Frequently Asked Questions

In most places, homeowners are allowed to do their own wiring. In some, they're not. Check with your local electrical inspector. Most places won't permit you to do wiring on other's homes for money without a license. Nor are you permitted to do wiring in "commercial" buildings. Multiple dwellings (eg: duplexes) are usually considered "semi-commercial" or "commercial". However, many jurisdictions will permit you to work on semi-commercial wiring if you're supervised by a licensed electrician - if you can find one willing to supervise. If you do your own wiring, an important point: Do it NEAT and WELL! What you really want to aim for is a better job than an electrician will do. After all, it's your own home, and it's you or your family that might get killed if you make a mistake. An electrician has time pressures, has the skills and knows the tricks of the trade to do a fast, safe job. Don't cut corners. Exceed specifications. Otherwise, the inspector may get extremely picky and fault you on the slightest transgressions. Don't try to hide anything from the inspector. Use the proper tools. Ie: don't use a bread knife to strip wires, or twist wires with your fingers. The inspector won't like it, and the results won't be that safe. And it takes longer. And you're more likely to stick a hunk of 12ga wire through your hand that way. Don't handle house wire when it's very cold (eg: below -10C or 16F). Thermoplastic house wire, particularly older types become very brittle.

The UL stands for "Underwriters Laboratory". It used to be an Insurance Industry organization, but now it is independent and non-profit. It tests electrical components and equipment for potential hazards. When something is UL-listed, that means that the UL has tested the device, and it meets their requirements for safety - ie: fire or shock hazard. It doesn't necessarily mean that the device actually does what it's supposed to, just that it probably won't kill you. The UL does not have power of law in the U.S. -- you are permitted to buy and install non-UL-listed devices. However, insurance policies sometimes have clauses in them that will limit their liability in case of a claim made in response to the failure of a non-UL-listed device. Furthermore, in many situations the NEC will require that a wiring component used for a specific purpose is UL-listed for that purpose. Indirectly, this means that certain parts of your wiring must be UL-listed before an inspector will approve it and/or occupancy permits issued.

USA: The following three books were suggested by our readers Residential Wiring by Jeff Markell, Craftsman Books, Carlsbad CA for $18.25. ISBN 0-934041-19-9. Practical Electrical Wiring Residential, Farm and Industrial, Based on the National Electrical Code ANSI/NFPA 70 Herbert P. Richter and W. Creighton Schwan McGraw-Hill Book Co. Wiring Simplified H. P. Richter and W. C. Schwan Park Publishing Co. The Electrician's Toolbox Manual Rex Miller Prentice Hall (ARCO) 1989 ISBN 0-13-247701-7 $11.00

One thing where things might get a bit confusing is the different numbers people bandy about for the voltage of a circuit. One person might talk about 110V, another 117V or another 120V. These are all, in fact, exactly the same thing... In North America the utility companies are required to supply a split-phase 240 volt (+-5%) feed to your house. This works out as two 120V +- 5% legs. Additionally, since there are resistive voltage drops in the house wiring, it's not unreasonable to find 120V has dropped to 110V or 240V has dropped to 220V by the time the power reaches a wall outlet. Especially at the end of an extension cord or long circuit run. For a number of reasons, some historical, some simple personal orneryness, different people choose to call them by slightly different numbers. This FAQ has chosen to be consistent with calling them "110V" and "220V", except when actually saying what the measured voltage will be. Confusing? A bit. Just ignore it. One thing that might make this a little more understandable is that the nameplates on equipment ofen show the lower (ie: 110V instead of 120V) value. What this implies is that the device is designed to operate properly when the voltage drops that low. 208V is *not* the same as 240V. 208V is the voltage between phases of a 3-phase "Y" circuit that is 120V from neutral to any hot. 480V is the voltage between phases of a 3-phase "Y" circuit that's 277V from hot to neutral. In keeping with 110V versus 120V strangeness, motors intended to run on 480V three phase are often labelled as 440V...

Fuses and circuit breakers are designed to interrupt the power to a circuit when the current flow exceeds safe levels. For example, if your toaster shorts out, a fuse or breaker should "trip", protecting the wiring in the walls from melting. As such, fuses and breakers are primarily intended to protect the wiring -- UL or CSA approval supposedly indicates that the equipment itself won't cause a fire. Fuses contain a narrow strip of metal which is designed to melt (safely) when the current exceeds the rated value, thereby interrupting the power to the circuit. Fuses trip relatively fast. Which can sometimes be a problem with motors which have large startup current surges. For motor circuits, you can use a "time-delay" fuse (one brand is "fusetron") which will avoid tripping on momentary overloads. A fusetron looks like a spring-loaded fuse. A fuse can only trip once, then it must be replaced. Breakers are fairly complicated mechanical devices. They usually consist of one spring loaded contact which is latched into position against another contact. When the current flow through the device exceeds the rated value, a bimetallic strip heats up and bends. By bending it "trips" the latch, and the spring pulls the contacts apart. Circuit breakers behave similarly to fusetrons - that is, they tend to take longer to trip at moderate overloads than ordinary fuses. With high overloads, they trip quickly. Breakers can be reset a finite number of times - each time they trip, or are thrown when the circuit is in use, some arcing takes place, which damages the contacts. Thus, breakers should not be used in place of switches unless they are specially listed for the purpose. Neither fuses nor breakers "limit" the current per se. A dead short on a circuit can cause hundreds or sometimes even thousands of amperes to flow for a short period of time, which can often cause severe damage.

Statistics show that fuse panels have a significantly higher risk of causing a fire than breaker panels. This is usually due to the fuse being loosely screwed in, or the contacts corroding and heating up over time, or the wrong size fuse being installed, or the proverbial "replace the fuse with a penny" trick. Since breakers are more permanently installed, and have better connection mechanisms, the risk of fire is considerably less. Fuses are prone to explode under extremely high overload. When a fuse explodes, the metallic vapor cloud becomes a conducting path. Result? From complete meltdown of the electrical panel, melted service wiring, through fires in the electrical distribution transformer and having your house burn down. [This author has seen it happen.] Breakers won't do this. Many jurisdictions, particularly in Canada, no longer permit fuse panels in new installations. The NEC does permit new fuse panels in some rare circumstances (requiring the special inserts to "key" the fuseholder to specific size fuses) Some devices, notably certain large air conditioners, require fuse protection in addition to the breaker at the panel. The fuse is there to protect the motor windings from overload. Check the labeling on the unit. This is usually only on large permanently installed motors. The installation instructions will tell you if you need one.

For a 20 amp circuit, use 12 gauge wire. For a 15 amp circuit, you can use 14 gauge wire (in most locales). For a long run, though, you should use the next larger size wire, to avoid voltage drops. 12 gauge is only slightly more expensive than 14 gauge, though it's stiffer and harder to work with. Here's a quick table for normal situations. Go up a size for more than 100 foot runs, when the cable is in conduit, or ganged with other wires in a place where they can't dissipate heat easily: Gauge Amps 14 15 12 20 10 30 8 40 6 65 We don't list bigger sizes because it starts getting very dependent on the application and precise wire type.

Overload is the most common reason for tripping. Too many things are plugged in or turned on in the circuit. Short circuit is another reason; this may be caused by faulty wiring, appliances or fixtures.

A GFCI or Ground Fault Circuit Interrupter is a special breaker or receptacle providing extraordinary protection from shock. The GFCI can tell if current as low as 5 milliamps is “leaking” out of a circuit to ground. If the GFCI senses this leakage it will de-energize the circuit. If this current is “leaking” through your body to ground because you have touched an energized piece of equipment you may feel a shock but it will be a very short duration before the circuit is turned off by the GFCI. These are the receptacles with the “test” and “reset” buttons found in many bathrooms and kitchens.

An AFCI is a special breaker intended to provide fire protection caused by arcing faults (small sparks) by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected. An AFCI recognizes the “signature waveform” of an arcing fault and shuts the power off to the circuit to protect against fire. AFCIs have been required in all new homes' bedrooms effective January 1, 2002. However if you have an old house you can still benefit greatly with AFCI protection. Powell Electric can install this fantastic safety technology today so your family will be protected by the best technology available.

You may be exceeding the maximum lamp wattage of the fixture. There should be a label inside the fixture. If the label is not there consider replacing the fixture. Do not exceed 60 watts for most ceiling fixtures. Many times vibration is the culprit in short bulb life. There are vibration resistant bulbs for ceiling fans and garage door openers and there are rough service bulbs for portable lights. Sometimes a porch light can have a shortened life due to a slamming door. A rough service bulb would do well in such a location. Sometimes there is more than 120 volts being brought into the light socket. You can purchase a 130 volt light bulb to take care of this problem.

The National Electrical Code which sets the minimum safety standards for the electrical system in your home, requires that each smoke detector in your home be hard-wired into your electrical system, battery back-up, in case your power goes out, and interconnected with your other smoke detectors. So if one goes off, they all go off. A smoke detector is required in each bedroom and one is required within six feet of your bedroom door. A C.O. detector is also required to be installed within 15 feet of your bedroom door is you have natural gas, propane or an attached garage.

A surge arrestor protects against surges, spikes, lightning etc. These surges may come down the utility line or they may come from within your home or nearby. This device will sacrifice itself to protect your electrical system and electronic equipment from surges. Many surge protectors simply plug into the wall and your equipment plugs into it. Using this kind of surge protection is less than optimum protection for the attached equipment. Powell Electric can install a whole house surge protector to protect everything in your house including phone and cable equipment. This is the best surge protection you can get and it protects everything in the house.

During normal operation, solid-state dimmers generate heat. A solid-state dimmer is roughly 98% efficient-2% of the power is dissipated as heat, causing the dimmer to feel warm to the touch. The closer a dimmer is run to full output and the higher the load (watts) on the dimmer, the warmer it will feel. This is perfectly normal and safe. Dimmers are designed to the strictest UL safety standard, and can handle their full rated load without overheating.

Trouble Shooting is the “detective work” involved in any electrical repair. We need every clue we can get to troubleshoot quickly and accurately. You can help us tremendously by giving us an accurate description of what the problem was, and also how and when the problem occurred. We test and examine your wiring of course, but first we listen to you, to find out exactly what you have experienced and why you have called us.

Trouble Shooting a problem usually does not take very long. The average time is about an hour. In many cases the solution to the problem is even easier than finding the problem. If we discover that the trouble shooting process will take additional time, we tell you before continuing.

Most of the time we send one technician. In some cases two technicians are necessary or more economical than one. In these cases, of course, we send two.

Answer: We will make every effort to do so. More often than not we can fix the problem very quickly the same day. Some problems require a county or city permit, an inspection, or the power company to do work and we have to work with these entity's schedules.