How many wires can safety How many wires can safety be installed in a junction boxbe installed in a junction box

or

2 things happen 2 things happen when current when current

flows in a flows in a conductorconductor

Heat is the arch Heat is the arch enemyenemy

of electrical of electrical equipment equipment

when current flowswhen current flows

Every conductor producesEvery conductor produces

so does the generated so does the generated heat within the boxheat within the box

so does the generated so does the generated heat within the boxheat within the box

As the number of conductors As the number of conductors in a junction box increases,in a junction box increases,

Installing the maximum Installing the maximum number of conductors in a number of conductors in a junction box is limited by junction box is limited by

heat dissipation heat dissipation

                    

 

The conductor length within The conductor length within the junction box is estimated the junction box is estimated

atatsix inches six inches of free conductorof free conductor

The six inches is The six inches is measured from the measured from the

termination point (splice termination point (splice or terminal screw)or terminal screw)

The six inches is The six inches is measured from the measured from the

termination point (splice termination point (splice or terminal screw)or terminal screw)

to the point of to the point of emergence from the emergence from the

cable sheathingcable sheathing

to the point of to the point of emergence from the emergence from the

cable sheathingcable sheathing

Or from where the Or from where the conductor exits a racewayconductor exits a raceway

Each 14 gauge Each 14 gauge conductor installed in a conductor installed in a

junction boxjunction boxrequires 2.0 cubic requires 2.0 cubic inches of spaceinches of space

Except the GROUNDINGconductor

Regardless of how many

are in the box

The TOTAL is always ONEGrounding conductor

ONE

The required spaceThe required space(2.0 cubic inches)(2.0 cubic inches)

is determined byis determined by

                                            

the the National National Electrical Code Electrical Code

BookBook

15 amps15 amps

14 gauge wire14 gauge wirehas a maximum has a maximum current flow ofcurrent flow of

14 gauge conductor14 gauge conductor

15 amps of current15 amps of currentproduces the maximumproduces the maximumallowableallowableinternal heatinternal heat

generated safely generated safely within thewithin the

If more than 15 If more than 15 amps of current amps of current

flowsflows

through a 14 through a 14 gauge conductorgauge conductor

the internalthe internalheatheat

will slowly COOK the will slowly COOK the conductorconductor

will slowly COOK the will slowly COOK the conductorconductor