Electrical

WIRING SIZES AND USAGE

It is very important that the correct size wire is used of the application. Wire size must be matched to the load and the breaker or fuse it will be connected to.

The use of wiring that is too light for the load, a breaker or fuse that has a higher amperage rating than the connected wire, or a connected appliance or sub panel that is too large for the wiring are the main causes of electrical fires.

Wiring used outside must be sunlight resistant outdoor wiring if above ground, and if going underground must be a type approved for burial. The use of indoor wire outside is prohibited due to the fact that it will deteriorate and fail.

Wiring size is measured by gauge.
The lower the number of the gauge the heavier the wire. The heavier the wire the more current it can carry.

   Suggested Gauge vs. Breaker Amp 
     For Copper branch circuits and feeders.

       Incoming Service Cable Sizing:

Common Usage -  Breaker / Fuse size:

*Check the rating on the appliance tag.

Wire type:
Romex wire - Non metallic sheathed cable (most common, white colored outer) used for most wiring jobs.
BX - Armor clad cable, wire in a flexible metal sleeve.

Size explained:
12/2 wire - 12 gauge, two wires & ground.
12/3 wire - 12 gauge, three wires & ground.

Colors explained:
Hot / Positive wire - Black or Red
Neutral wire - White
Ground wire- Uncovered copper

NOTE: A heavier wire may be used than the size required, a lighter gauge can never be used. Extension cord wire, lamp wire or wire less than 14 gauge can not be used for any wiring.

<Back 

| Welcome to BIS | About BIS | Home Inspections | Get Started  | Technical FAQ | Contact us |