[willc86]

im not sure how this was started? the connections seemed fine?

 

[craig11152]

At the 28 second mark it says "Please note the connection was intentionally created as a loose connection in order to immediately simulate a glowing connection"

I'm no electrician so I'm not sure what all that means except the connections were not fine....intentionally.

 

[beenthere]

Most likely, the wire nut was only set on top of the wires, not screwed onto them.

 

[willc86]

Most likely, the wire nut was only set on top of the wires, not screwed onto them.

stupid question, but what do you mean wire nut was set on top and not screwed in? Sorry just trying to understand this. I plan to do my own basic electrical (i will hire electrician for more moderate to complex) so just trying to get basic understanding on how fires get started

electrical work also interests me very amusing to me haha

 

[Bondo]

so just trying to get basic understanding on how fires get started

Ayuh,.... Electrical connections must be between clean metal wires, 'n must be Tight connections,.....

Corrosion, or a loose connection creates resistance,...

With electricity, resistance equals heat, heat equals fire, eventually,...

 

[joed]

I'm not sure what the point of the video is other than to show that loose connections are not good and j boxes are goo to contain the fire.
If they had use an AFCI it might have tripped as it is designed to detect this type of fault. A GFCI is not designed for this type of fault.

 

[spaceman spif]

If the connections used to hold the wires together are not tight, it can create a small gap between the conducting wires. The electric current can jump that gap, creating a spark - just like static electricity. Get enough sparks and you can set something on fire.

 

[intelpcguy]

For your basic 20 amp 12/2 romex type of circuit ( for receptacles for example ), you need to ensure each connection point ( wire nuts junctioning wire to wire, wire to the screw terminals to a receptacle, ) are mechanically sound and tight. Pretwisting 2 or more wires with a line mans pliers before applying a wire nut ( as well as using the correct sized wire nut , proper amount of stripped lead out on the wires ) is a good practice for ensuring tight, trouble free joints.

The same applies to other wire sizes, be it solid or stranded. With stranded unless you have side plates to lock on to devices, they need to be pigtailed in solid or have the proper crimp on ring or fork terminal connectors.

Most wire nuts are rated for 2 wire ( appropriately sized ) junctioned with no pretwist, provided you tighten the wire nut ( and i the process end up twisting the wire ).

Devices ( switches and receptacles ) should never be back stabbed, but wire wrapped clockwise on the screw terminal.

Of course if you apply more amps continuously than the wire is rated for ( 30 amps on a 20 amp rated wire for example ) you'll get insulation failure and probably a fire as well. So proper over current protection of the circuit is vital as well.