Calculations:Electrical Design Guideline: Difference between revisions

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## Provide manual checks of pertinent results (e.g. service size, main feeder voltage drop) for computer generated output.
## Provide manual checks of pertinent results (e.g. service size, main feeder voltage drop) for computer generated output.


=== Basic Electrical Engineering Formulas ===


==== List of Symbols ====
''V'' - Voltage (volts)


''I'' - Current (amps)
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''R'' - Resistance (ohms)
 
''X'' - Reactance (ohms)
 
''Z'' - Impedance (ohms)
 
''W'' Real Power (watts)
 
''θ'' - Phase angle whose cosine is the power factor
 
''eff'' - Efficiency
 
==== Direct Current (DC) Formulas ====
'''Basic Formulas'''
 
===== Volts ===== 
 
: <math>V=I \times R</math>
: <math>V={P \over I}</math>
: <math>V=\sqrt{P \times R}</math>
 
===== Power =====
 
: <math>P=V \times I</math>
: <math>P=I^2 \times R</math>
: <math>P={V^2 \over R}</math>
 
===== Current =====
 
: <math>I={P \over V}</math>
: <math>I={V \over R}</math>
: <math>I=\sqrt{P \over R }</math>
 
==== Alternating Current - Single Phase ====
''Note: V denotes line to neutral voltage.''
 
'''Basic Formulas'''
 
Volts
: <math>V=I \times Z</math>  (''volts'')
 
Power Factor
: <math>pf=cos \phi</math>
: <math>pf={P \over S}</math>
 
Apparent Power '''''S'''''
: <math>S=V \times I</math>  (''volt-ampere'')
 
Reactive Power '''''Q'''''
: <math>Q=V \times I \times sin \phi</math>  (''volt-ampere-reactive'')
 
Real Power '''''P'''''
: <math>P=V \times I \times cos \phi</math>  (''watts'')
 
==== Alternating Current - Three Phase ====
'''Under Construction'''
 
=== Sample Calculations- ===
'''Under Construction'''

Latest revision as of 16:11, 10 November 2023

Electrical Design Calculations Guideline

Figure 1 Power Line

Electrical design calculations guidelines establishes minimum requirements for generating electrical calculations on projects. Electrical calculations should be made for all projects that include electrical components. Design calculations may be made either manually or by computer programs. At a minimum, the following types of calculations should be made where applicable:

* Load calculations
* Conductor sizing
* Conduit sizing
* Motor branch circuit sizing
* Power factor improvement
* Transformer primary and secondary circuit sizing
* Voltage drop
* Motor starting voltage dip
* Short circuit analysis
* Lighting levels
* Grounding in substations where step potentials are of concern
* Harmonic distortion analysis
* Cable pulling calculations
* Generator capability/motor starting.

Basic Requirements for Electrical Calculations

The following are basic requirements for electrical calculations:

  1. Non-computer generated calculations must be on standard project calculations sheets.
  2. Calculations generated by computer programs must conform with the following procedures:
    1. Include all heading information on each sheet
    2. Insert comments wherever possibly to clarify concepts and actions taken in the computer input
    3. Provide clear documentation of electrical geometry, support conditions, load application, and load requirements
    4. Provide where practicable sketch of model indicting nodes, materials, connectivity, etc.
    5. Provide electronic copy on CD or other suitable device of analysis input and output with hard copy calculations.
    6. Provide manual checks of pertinent results (e.g. service size, main feeder voltage drop) for computer generated output.


Calculations:Electrical Design Guideline/Basic Electrical Engineering Formulas