A-Line Electrical Supply, Inc.

"The Electrician's Source"

Home

About Us

Shop Online

Energy Star

Manufacturers

Reference

NYC Reference

Directions

Contact Us

Common Electrical Terms, Formulas and Charts

Below are some commonly used electrical reference items.


Common Electrical Terms Simplified
  • Ampere - rate of flow of current 
  • Kilovolt Ampere - one kilovolt ampere - KVA - is equal to 1,000 volt amperes
  • Kilowatt- Unit of power - KW - equal to 1000 watts
  • Ohm - unit of resistance 
  • Power Factor - ratio of watts to volt amperes
  • Volt - unit of electrical potential or motive force  
  • Volt Ampere - product of volts and amperes as shown by a voltmeter/ammeter 
  • Watt - unit of electrical energy or power


Portable Cord Letter Connotations
  • S = 600 Volt Service Cord
  • J = Junior Service - 300 Volt
  • T = Thermoplastic
  • E = Elastomer - thermoplastic that looks and feels like rubber
  • O = Oil Resistant Outer Jacket
  • OO = Oil Resistant Outer Jacket and Oil Resistant Insulation
  • W = CSA Weather and Water Resistant (approved for indoor and outdoor use)
  • SPT-1 = All thermoplastic construction, parallel jacketed. 300 Volt (18 gauge)
  • SPT-2 = Same as SPT-1, but with heavier construction (18-16 gauge)
  • SPT-3 = Same as SPT-2, but with heavier construction (18-10 gauge)
  • SRDT = Portable dryer or range cord, parallel jacketed. 300 Volt
  • HPN = Two-conductor, neoprene insulated heater cord. Parallel construction, damp location. 300 Volt
Example: 12-3 SJOW = 12 Gauge, 3 Conductor, Service Junior 300 Volt, Oil and Weather resistant


Common Electrical Formulas, NEMA Charts & Definitions

KW = Kilowatts
KVA = kilovolt/amperes
HP = horsepower
% Eff. = percent efficiency


To Find

Single Phase

Amps

Amps = Watts ÷ Voltage

Watts

Watts = Amps x Voltage

Voltage

Voltage = Watts ÷ Amps



To Find

Three Phase

Amps

Amps = Watts ÷ Voltage ÷ 1.73

Watts

Voltage x Amps x 1.73



To Find

Single Phase

AMPERES when KVA is known

KVA X 1000
Volts

AMPERES when horsepower is known

HP X 746
Volts
X % Eff.X Power Factor

AMPERES when kilowatts are known

KW X 1000
Volts
X Power Factor

KILOWATTS

Amps X Volts X Power Factor
1000

KILOVOLT/
AMPERES

Amps X Volts
1000

HORSEPOWER

Amps X Volts X % Eff. X Power Factor
746

WATTS

Volts X Amps X Power Factor

If power factor is unknown, multiply by 1, use result as a guide.



To Find

Three Phase

AMPERES when KVA is known

KVA X 1000
Volts X 1.73

AMPERES when horsepower is known

HP X 746
Volts
X 1.73 X % Eff. X Power Factor

AMPERES when kilowatts are known

KW X 1000
Volts
X 1.73 X Power Factor

KILOWATTS

Amps X Volts X 1.73 X Power Factor
1000

KILOVOLT/
AMPERES

Amps X Volts X 1.73
1000

HORSEPOWER

Amps X Volts X 1.73 X % Eff. X Power Factor
746

WATTS

Volts X Amps X 1.73 X Power Factor

If power factor is unknown, multiply by 1, use result as a guide




To Find

Direct Current

AMPERES when horsepower is known

HP X 746
Volts
X % Eff.

AMPERES when kilowatts are known

KW X 1000
Volts

KILOWATTS

Amps X Volts
1000

HORSEPOWER

Amps X Volts X % Eff.
746

WATTS

Volts X Amps




NEMA Enclosure

Definition

Type 1

Indoor use, limited protection

Type  2

 Indoor use, greater protection against water and debris

Type 3

Outdoor use, limited protection

Type 3R

Outdoor use, greater protection against water, debris and ice

Type 4

Indoor or outdoor use, greater protection against hose directed water, debris and ice

Type 4X

 

Same as Type 4, corrosion resistant (normally Stainless Steel)

Type 6

Same as Type 4, with temporary protection from limited submersion




Overcurrent protection for conductor types marked (*) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper. See NEC 240-2 for motor & welders overcurrent protection exceptions. See NEC 240-3D.
For ambient temperatures other than those noted above, see NEC tables 310-16 & 310-18 Footnotes.



Disclaimer

This material is presented as a guide only. A-Line Electrical Supply, Inc. assumes no responsibility for any information or results from the use of such information. The results produced by these calculators and general information are not guaranteed to be correct or applicable in any or all situations. The user must have a thorough understanding this trade and any applicable Electrical Codes where work is being performed. It is the users responsibility to verify compliance with local jurisdictions.


Home
About Us

Manufacturers
Reference Information
NYC Reference Information
Directions
Contact Us
 

© 2005-2022 A-Line Electrical Supply Inc. 8704 Foster Ave Brooklyn, NY 11236 (718) 257-4100 Fax (718) 257-5315