| WATTS = POWER | The amount of electrical energy required to convert volts into heat energy. |
|---|---|
| AMPERES = CURRENT | The flow of electrical energy |
| VOLTS = PRESSURE | Measurement of force required to move current through a circuit |
| WATTS | WATTS = AMPS x VOLTS |
|---|---|
| AMPS | AMPS = WATTS / VOLTS |
| VOLTS | VOLTS = WATTS / AMPS |
The most important aspect of calculating amp draw for a prefabricated office is to get information from the customer as to what equipment or machines are going to be in the office. Most normal office items (ie. Personal computers, monitors, printers, calculators, fax machines, etc…) do not draw enough amps to be concerned about. The office items that have large amperage requirements are the ones to find out about. These include main frame computers, vending machines, space heaters, HVAC systems, welding equipment, etc… We would also like to know if the office or an area in the office is going to have a concentration of machines (like a typing pool or copier room).
Based on architectural graphic standards guidelines, listed below are some general rules to figure power requirements:
| Average electrical loads for typical spaces in watts per square foot | |
|---|---|
| Room Type | Watts/SqFt |
| general office | 4 |
| copier rooms | 15 |
| conference rooms | 1 |
| word processing | 5 |
| computer rooms | 40 |
Note: these loads do not include HVAC or special equipment requirements.
20′ x 40′ office with 2-wall mount A/C-heat units
800 sq. ft. X 4 = 3200 watts
3200/120v = 26.7 amps
2-HVAC units @ 20 amps each
Total amp draw for office: 66.7 amps
Resources