Electric Meters

A watt-hour meter measures and records the quantity of K electric power consumed over time. Meters are supplied by the utility, and are always placed ahead of the main disconnect switch so that they can't be disconnected. Meters are located outside at the service point or inside the building, where they must be kept readily accessible to utility personnel. Manual reading of kilowatt-hour meters of individual consumers is labor intensive. Meters are often inaccessible, and meter readers may face hostile dogs and inclement weather. Remote reading of inside meters is now common. Programmable electro-optical automatic meter-reading systems can be activated locally or from a remote location. Meter data is transferred electrically to a data processing center, where bills and load profiles are prepared, and area load

Three lines from power company

Service entrance head

• Grounding electrode conductor

Ground rod or cold-water service to metal pipes underground —

• Grounding electrode conductor

Ground rod or cold-water service to metal pipes underground —

Figure 28-2 Electrical service entrance.

patterns can be studied. Miniature radio transmitters on the meter can be remotely activated to transmit current kilowatt-hour data, which is encoded and recorded automatically. Such meters are more expensive but are replacing conventional units, resulting in a large reduction in labor costs, and better quality and quantity of data. Even with remote readers, the meter must be available for inspection and service.

Within the meter, the electricity drives a tiny motor at a speed proportional to the rate at which current passes through the wires. The motor advances pointers on dials by means of gears, and records the quantity of energy consumed in units of kilowatt-hours. In single-occupancy buildings or where the landlord pays for electrical service, there is one meter. For multitenant buildings, banks of meters are installed so that each unit is metered separately. A single meter is not allowed in new multiple dwelling constructions by federal law, as tenants tend to waste energy when they don't have to pay for it directly.

Advanced smart meters are now available that tell you how much electricity really costs right this hour or minute, and how much it would be worth to you, in real money, to conserve. Electricity prices are set largely by what it costs to produce enough electricity for the busiest few hours of the year, with prices rising dramatically when demand threatens to outstrip supply. A considerable portion of what you pay for electricity each month covers the risk of these rare price spikes and the cost of building special power plants like jet turbines and hydroelectric reservoirs that are used only rarely to cover demand peaks. If enough people had electric meters that said, in effect, you can save 25 cents by waiting until midnight to dry your clothes, demand could be measurably reduced, enough to trim price spikes significantly.

Electric utilities already offer this type of service to their largest industrial and institutional customers, giving them bounties to shut down factories or conserve power when shortages and rolling blackouts loom. Utilities are also initiating Web sites that allow participating businesses to get real-time electric price information, with incentives to cut back use when prices soar.

Companies are developing technologies for the small-user market, such as a device that connects home and business electric meters, and conceivably individual appliances, through the Internet to electric utilities. Utilities would be able to collect billing information directly over the Internet, rather than sending out meter readers. Puget Sound Energy in suburban Seattle has outfitted 1 million homes and businesses with advanced meters that take readings every 15 minutes and send them back wirelessly. Eventually, utilities may be able, with customer's approval, to control things inside the house like thermostats, electric heaters, clothes dryers, and dishwashers. This would allow consumers to save energy and electric costs without having to repeatedly check their electric meters or the utility's Web site.

Solar Power

Solar Power

Start Saving On Your Electricity Bills Using The Power of the Sun And Other Natural Resources!

Get My Free Ebook


Post a comment