Shocking news! - determining the electrical capacity of home offices - Office Design

Home Office Computing, April, 1993 by Bob Duke

It Takes Amps to Run Lamps. Make Sure Your Circuits Will Bear the Load.

Electricity is the lifeblood of your home office, and you probably never think about it. It's just there. Your computer, answering machine, copier, and other equipment all rely on the electricity, and you rely on the equipment. When your office equipment fails, your business fails; data is lost, schedules are missed, and invoices aren't mailed.

Not knowing your home office's electrical capacity and requirements is a gamble. An inadequate and overburdened electrical system can cause downtime, damage equipment, impede work, and, in the worst case, result in an electrical fire.

Electrical engineer and licensed electrician Abe Khadem from Costa Mesa, California, says the average home office is protected by one 15-or 20-ampere (amp) circuit breaker. "If the circuit breaker is defective, the load too great, and the wire gauge too small," Khadem says, "there can easily be a fire from a circuit overload."

The typical home office was never intended to be an office in the first place. It is most often a converted bedroom in a 10-to-30-year-old house that has 110-volt, 100-amp electrical service. The room itself usually has three, two-receptacle, 15-amp service wall outlets. One of the outlets is normally controlled by a wall switch at the entry door. Sound familiar?

The often slow and fragmented way home-office equipment and furnishings are accumulated easily masks the buildup of high electrical loads that can be troublesome or dangerous if they remain unknown. When I recently did an electrical inventory of my home office, I was amazed to discover the potential electrical load of my equipment totaled 32.5 amps (see "Power Up?," above, for details). I have a 20-amp circuit breaker.

Office copiers are the single biggest home-office electrical load, in electrician Khadem's experience. "If it's a very big copier, I recommend purring it on its own circuit with its own breaker," Khadem says.

ONLY A TEST

Without the help of an electrician and special equipment, it is hard to know whether normal home-office operations are going to overload your electrical circuit. Generally not all equipment is drawing maximum power at the same time. You can tell whether your circuit may be nearing its capacity, though, with a simple experiment. Turn on all the equipment you normally use and have it perform its normal functions-leave the copier copying, the printer printing. "Then go to the home-office circuit break-er," Khadem says, "and listen to whether the breaker is making a buzzing sound or see if it is warm to the touch. Either sign is an indication the breaker is near its capacity."

Khadem warns that, besides overloading the circuit, other common home-office electrical faults include ganging too many plugs into too few receptacles and overloading the 15-amp capacity of the receptacles, using ungrounded receptacles, and using undersized, low-quality extension cords. "The common cheap, flat, two-wire extension cords are often undersized and are too easily damaged by pets and furniture," Khadem says. "I recommend using round, three-conductor cords of at least 12-gauge wire."

GANG OF FOUR

A safe way to increase the number of receptacles in your home office, without putting the whole load on the circuit breaker, Khadem says, is to use a ganged receptacle box with its own circuit breaker. These are metal or plastic boxes containing a gang of four or six electrical receptacles connected to the box's own circuit breaker. The box is plugged into a wall outlet with its own heavy-duty extension cord, then equipment is plugged into the box, and the house circuit is protected by the receptacle's breaker instead of the main panel's breaker. The boxes are available at any hardware or home-improvement center for $10 to $20.

Modifying an existing electrical system can be expensive, so you may be better off managing your power requirements than trying to add capacity. However, if you are already tripping your home-office circuit breaker, if the lights dim when your laser printer comes on, or if there are signs of power surges on your computer monitor, it is time to call an electrician.

If you are remodeling or involved in new construction, this would be the best time to look at your home-office electrical needs. "Nobody usually thinks of things like this in time," Khadem says, "but during construction for a home office, I would recommend two independent circuits, with one dedicated to sensitive equipment. Doing this at the stud stage of construction would cost only about $75. Doing the same thing later would cost at least $400 or $500."

To calculate the maximum electrical power requirements of your home office, locate the power-rating label affixed on every piece of electrically powered equipment in your office and total the watts or amperes. For incandescent lighting, read the wattage rating on the bulbs, and for fluorescent, read the label on the fixture. Convert all power requirements to amperes by dividing the number of watts by 110. The ampere is a more convenient measure for this purpose because circuit breakers are rated in amperes. Next, compare your calculated amperes to the circuit breaker rating marked on the front or side of the circuit breaker handle at the electrical panel. The more your potential load exceeds the circuit breaker's rating, the greater the possibility for overloading the circuit, and the more care you must take to control the load.