tag:blogger.com,1999:blog-46103723619383388462024-03-06T23:57:48.200+08:00KW HR POWER METERING INFORMATION SITEyour revenue, our concernStanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.comBlogger42125tag:blogger.com,1999:blog-4610372361938338846.post-50816177057762837852013-11-02T12:33:00.002+08:002013-11-02T12:33:34.948+08:00UNDERGROUND SERVICES AND UNDERGROUND WIRING
ADVANTAGES OF UNDERGROUND WIRING
The advantages of underground electric service are attractiveness (lack of physical and visual clutter overhead), service reliability, and long life. The principal disadvantage is high cost. To overcome this, utilities frequently use direct burial techniques that, by eliminating a raceway, reduce costs considerably.
Because direct buried cable cannot be Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com3tag:blogger.com,1999:blog-4610372361938338846.post-23379445641942869802013-10-12T22:02:00.001+08:002013-10-12T22:02:39.809+08:00PARTS OF ELECTRIC SERVICE ENTRANCE BASICSHow to install service entrance? You will only know it if you know its parts. The details of how the service lateral or triplex cable provided by the electrical utility is fastened and spliced to the customer’s service point are illustrated in Fig. 5-3.
The bare neutral/grounding cable that supports the triplex is fastened at one end to the utility pole and the other end is fastened at the Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com4tag:blogger.com,1999:blog-4610372361938338846.post-85633532915014190812013-06-16T11:11:00.001+08:002013-06-16T11:12:12.291+08:00GUIDE FOR INVESTIGATION OF CUSTOMERS’ HIGH-BILL ELECTRICITY INQUIRIES ON THE CUSTOMERS’ PREMISES
As a representative of the company, an employee who is assigned to investigate a customer’s inquiry concerning his billing has a dual responsibility. First, make absolutely certain that all service used by the customer is being accurately registered on the meter. Attempt to explain some of the metering factors to a customer who does not understand them to assure the customer of the accuracy of Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-38219137365670273452013-06-16T11:07:00.003+08:002013-06-16T11:12:00.952+08:00GOOD PRACTICES FOR METERING PERSONNEL
Efficient metering personnel will make good installations. In doing so, they will observe certain practices that will be helpful to both their company and the customers. These good practices have many benefits. They insure good service by preventing unnecessary outages.
They insure good customer relations by preventing damage to the customer’s equipment. Also, the meter employee will not have Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-60106204778815592582013-06-16T11:02:00.001+08:002013-06-16T11:02:58.702+08:00RESIDENTIAL WIRING GROUNDING SYSTEM BASIC INFORMATIONResponsibility for adequate grounding on the customer’s premises lies with the customer and not with the utility company.
Grounding is one of the most important subjects covered by the National Electrical Code and this code is very clear in regard to the purposes of grounding. It reads:
Circuits are grounded to limit excessive voltages from lightning, line surges, or unintentional contact with Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-66662507563427455012013-06-15T21:49:00.000+08:002013-06-15T21:49:01.509+08:00MAGNETIC CONTACTORS - BASIC INFORMATION
WHAT ARE MAGNETIC CONTACTORS?
A contactor is a switch. Instead of a handleoperated, movable blade, a contactor uses contact blocks of silver-coated copper, which are forced together to make (close) or are separated to break (open) a circuit.
The common wall-mounted light switch is a small, mechanically operated contactor.
A relay is an electrically operated contactor. Most Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-15814026030732442432013-06-14T20:26:00.000+08:002013-06-14T20:26:27.310+08:00COST OF USING ELECTRICAL ENERGY BASIC INFORMATION
POWER CONSUMPTION COMPUTATION TUTORIALS
A watt-hour meter is always connected into some part of the service-entrance equipment to record the amount of energy used. Billing by the utility is generally done on a monthly basis.
The meter might be mounted on the side of the house or on a pedestal somewhere on the premise on the lot line. The utility makes this decision.
The residence discussed Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-79855441373734257472013-06-13T22:58:00.001+08:002013-06-13T22:58:21.812+08:00SERVICE ENTRANCE CABLE INSTALLATION BASIC INFORMATION AND TUTORIALSThe installation of service-entrance cable is covered in NEC Article 338. Service-entrance cable for above ground use is supplied in one of two varieties. A “U” style consists of two insulated conductors with a bare neutral wrapped around the insulated conductors in a spiral configuration.
At terminations, the spiral neutral conductor is unwound and twisted together to form the third or neutral Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-21703485338104159722013-06-11T19:17:00.001+08:002013-06-11T19:17:21.215+08:00CALCULATING THE MELTING POINT OF A COPPER CONDUCTOR TUTORIALS
The melting point of a copper conductor can be calculated by using these values:
• 1 ampere (RMS current)
• for 5 seconds
• for every 16.19 circular mils of cross-sectional area of the conductor.
NEC 250.122(B) states that if the ungrounded conductors are sized larger for any reason, the equipment grounding conductor shall be increased proportionately, based on the cross-sectional area of Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-34899322792383906352013-06-11T19:03:00.002+08:002013-06-11T19:05:03.323+08:00SINGLE PHASING OF MOTORS BASIC INFORMATION
A 3-phase motor can be subjected to a situation referred to as “single phasing.” Single phasing means one phase is open—somewhere. See Figure 1 and Figure 2.
FIGURE 1
Example of secondary single phasing. The windings in the motor are wye-connected. When a secondary single phasing occurs, the current in one phase drops to zero amperes and the current in the other two phases increases to Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-36097590807138045512013-06-09T17:40:00.002+08:002013-06-09T17:40:57.602+08:00SERVICE ENTRANCE AND NEUTRAL CONDUCTOR SIZING BASIC INFORMATION
Service-Entrance Conductor Size
A set of service-entrance conductors is installed from the termination box to each service disconnecting means. The minimum size of the service entrance conductors is determined by performing a load calculation in accordance with NEC Article 220.
On reviewing the load calculation form for any of the occupancies, you will find the service disconnecting
means and Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-1780758616979737732013-06-09T17:35:00.001+08:002013-06-09T17:35:07.510+08:00EXHAUST FAN INSTALLATION CONSIDERATIONS BASIC INFORMATION AND TUTORIALS
To turn the exhaust fan on and off, an ac general use, single-pole snap (toggle) switch is installed on the wall below the fan. The electrician will install an outlet box approximately 1 ft from the ceiling (see the electrical plan), from which he will run a short length of flexible metal conduit to the junction box
on the fan.
The fan exhausts the air from the Bakery. The fan is installed Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-20905011929580130792013-05-26T10:34:00.000+08:002013-05-26T10:34:41.069+08:00AIR CONDITIONER AND HEATERS ENERGY RATINGS EXPLANATION AND TUTORIALS
Energy ratings indicate the efficiency of heating and cooling equipment. Basically, these ratings are a comparison of output (heating or cooling) to input (electricity, gas, or oil).
Energy Efficiency Rating (EER)
Cooling efficiency rating for room air conditioners. The ratio of the rated cooling capacity in Btu per hour divided by the amount of electrical power used in kilowatt-hours.
The Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-64068587019414514912013-05-26T10:25:00.001+08:002013-05-26T10:25:33.567+08:00SUBMERSIBLE PUMPS BASIC INFORMATION AND DIAGRAMPARTS OF SUBMERSIBLE PUMP
figure 1
A submersible pump consists of a centrifugal pump driven by an electric motor. The pump and the motor are contained in one housing, submersed below the permanent water level, within the well casing.
The pump housing is a cylinder 3–5 in. in diameter and 2–4 ft long. When running, the pump raises the water upward through the piping, to the water tank. Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com23tag:blogger.com,1999:blog-4610372361938338846.post-8025660314995661932013-05-25T21:59:00.000+08:002013-05-25T21:59:19.771+08:00THERMAL (LAGGED DEMAND) ELECTRICITY METERSElectromechanical
In the electromechanical thermal or lagged-type demand meter, the pointer is made to move according to the temperature rise produced in elements of the meter by the passage of currents. Unlike the integrating demand meter, the lagged meter responds to load changes in accordance with the laws of heating and cooling, as does electrical equipment in general.
Because of the time Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-13140912578767400312013-05-25T21:55:00.001+08:002013-05-25T21:55:26.954+08:00ELECTRICITY METER (KW-HR) ANTI CREEP HOLES
Without anti-creep holes, the interaction of the voltage coil and the light-load adjustment might provide enough torque to cause the disk to rotate very slowly when the meter was energized, but no current flowing.
This creep would generally be in a forward direction, because the light-load adjustment is so designed that it helps overcome the effects of friction and compensates for Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-71081444485667620382013-05-25T21:45:00.002+08:002013-05-25T21:45:33.800+08:00RACEWAY SIZING AS PER NEC BASIC INFORMATIONIn keeping with the emphasis of the metric system of measurements in the NEC, a Metric Designator has been introduced to provide an equivalency to the inch system of measurement for circular raceways
used for many years as shown in table below.
You may have noticed the NEC uses the term “trade size” rather than simply “size” or “size in
inches” to indicate the size of circular raceways. ThereStanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-59740071261680636902013-05-24T23:08:00.004+08:002013-05-24T23:08:40.605+08:00ADVANTAGES OF IMPLEMENTING SMART GRIDWHY IMPLEMENT SMART GRID NOW?
Since about 2005, there has been increasing interest in the Smart Grid. The recognition that ICT offers significant opportunities to modernise the operation of the electrical networks has coincided with an understanding that the power sector can only be de-carbonised at a realistic cost if it is monitored and controlled effectively. In addition, a number of more Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-25355645758780894552013-05-24T23:02:00.001+08:002013-05-24T23:02:07.853+08:00NEC CONTINUOUS LOAD CALCULATION FOR ELECTRICAL SYSTEM DESIGNSeveral NEC sections contain the very important requirement to size conductors and overcurrent devices at 100% of the noncontinuous loads plus 125% of the continuous loads. This takes into account heat buildup resulting from the current flowing through the conductors and overcurrent devices for an extended period of time.
These requirements are found in NEC 210.19(A)(1) for branch circuits, Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com1tag:blogger.com,1999:blog-4610372361938338846.post-13519757807972978592013-05-23T22:42:00.001+08:002013-05-23T22:42:07.817+08:00WIRING DIAGRAMS FOR A TYPICAL STANDBY GENERATOR
For simplicity, the diagrams presented are one-line diagrams. Actual wiring consists of two ungrounded conductors and one grounded “neutral” conductor. Equipment grounding of all of the components is accomplished through the metal raceways that interconnect the components.
The neutral bus in a panelboard that serves selected loads must not be connected to the metal panelboard enclosure. Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com3tag:blogger.com,1999:blog-4610372361938338846.post-55411688813853262762013-05-23T22:17:00.000+08:002013-05-23T22:17:06.866+08:00UNGROUNDED SYSTEM BASIC INFORMATION
In this type of system, a phase-to-earth
fault only produces a weak current through the
phase-to-earth capacity of the fault-free
phases.
It can be shown that Id = 3 CwV
V being the simple voltage,
C the phase-to-earth capacity of a phase,
wthe frequency of the system (w = 2* pi
*f).
The Id current can remain for a long time,
in principle, without causing any damage since
it Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-16814278971495201092013-05-20T21:15:00.000+08:002013-05-20T21:15:20.694+08:00INSULATION RESISTANCE TEST AND HI POT TESTING BASICS
Insulation resistance tests are typically performed on motors, circuit breakers, transformers, low-voltage (unshielded) cables, switchboards, and panel boards to determine if degradation due to aging, environmental, or other factors has affected the integrity of the insulation. This test is normally conducted for 1 min, and the insulation resistance value is then recorded.
As mentioned earlier,Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-76239542932338258812013-05-18T13:44:00.002+08:002013-05-18T13:44:42.115+08:00AUTOMATIC METER READING (AMR) TECHNOLOGIES BASIC INFORMATION AND TUTORIALS
PURPOSE AND ADVANTAGE OF AMR
To eliminate meter access problems and data entry errors while improving overall meter reading efficiency, many utilities are implementing Automatic Meter Reading (AMR) technology. The AMR technology enables utilities to collect meter data without having to visit the meter. Nationwide, an increasing number of electric, gas, and water utilities are installing these Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-15904809406140709462013-05-18T13:36:00.001+08:002013-05-18T13:36:32.029+08:00DYNAMOMETER POWER FACTOR AND PHASE ANGLE MEASUREMENT
Measurement of Power Factor and Phase Angle
A variation of the fundamental electrodynamometer instrument is used to measure power factor or the phase angle, and is called the crossed-coil type. See Figure 6-7. In this design the moving element consists of two separate coils, instead of one which are mounted on the same shaft and set at an angle to each other.
The lead-in springs or spiralsStanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0tag:blogger.com,1999:blog-4610372361938338846.post-52437120132920550722013-05-18T13:31:00.001+08:002013-05-18T13:31:40.276+08:00THREE-WIRE,THREE-PHASE DELTA SERVICE METERING TUTORIALS
Two-Element (Two-Stator) Meter
The three-wire, three-phase delta service is usually metered with a two-stator meter in accordance with Blondel’s Theorem. The meter used has internal components identical to those of network meters, but may differ slightly in base construction.
Typical meter connections are shown in Figure 7-4. In the top element (stator) of the meter the current sensor carries Stanlyhttp://www.blogger.com/profile/17984769319085340260noreply@blogger.com0