Electrical Design in Modular Offices

All modular electrical components supplied by Starrco are UL listed. The modular power systems including modular lighting systems have standard components that are designed for use with a 120/240-vo1t single-phase system operating at 60 Hz.

Modular components for three-phase and other special requirements are available as special orders.

The standard light fixture is a 2′ x 4′ recessed fluorescent troffer designed for 4-32 watt bulbs. Total watts per light fixture are 128.

Determining the modular lighting systems needed for a particular application can be a complex process involving several different formulas. Listed below are some simplified guidelines to help figure the quantity of lights needed. (Starrco standard modular lighting design is based upon 70-foot candles):

Recommended Foot Candles of Lighting
Foot Candles 30FC 50FC 70FC 100FC 150FC
Rooms lavatories office area classroom drafting fine drafting
conference room stores proof reading general assembly display lighting
cafeteria reading room general assembly testing fine assembly
corridors rough assembly inspection inspection testing
deskwork testing counter display prolonged seeing


Quantity of Light @ 50FC = Square foot of room x 1.5 watts / 160 watts
Quantity of Light @ 70FC= Square foot of room x 2.0 watts / 160 watts
Quantity of Lights @ 100FC = Square foot of room x 3.0 watts / 160 watts

Note: to reduce the quantity of lights needed for an entire area, concentrate the lighting in the areas where the actual work is being performed. Limit the lighting in common or non-critical areas. This not only reduces the number of lights in an area, but will also reduce cooling requirements and maintenance costs.

Starrco’s standard portable building design is to supply an outlet approximately every 8 linear feet of wall, unless specified otherwise. A simple design alternative is to put outlets in the areas they are needed (i.e. around work stations, equipment, etc…)

Outlets for computers, air conditioners, copiers or equipment with motors should be on separate circuits. Do not count on these outlets for general usage.

Starrco’s standard circuit breaker box is a 120/240v single-phase panel capable of handling up to twelve single pole breakers. We use the following guidelines for determining the quantity of breakers supplied with each circuit breaker box:

Ten (10) lights per light switch or 20 amp breaker

Eight (8) 120v duplex receptacles per 20-amp breaker. Note: the types of modular electrical components being used may affect the quantity of receptacles assigned to each breaker. For example, if space heaters are going to be used in the office, the quantity of receptacles per breaker should be reduced because of the potential amp draw of the heaters. For more help determining electrical needs, visit our Calculating Amp Draw page.

Air conditioners and HV AC units are on separate power circuits.

Items requiring 220-250v will be on a separate two-pole breaker.

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