Post by rdstarwalt on Mar 25, 2012 8:42:57 GMT -6
At 3:59, I am pretty sure Trent experienced a ground fault situation.
By looking at the video of his 'power supply' I made a sketch of what I suspect happend.
The sketch is attached.
Trent later says that the fishing line broke. When it broke, the nichrome wire, which has electric potential and not just temperature, touched the concrete he was working on.
Once on the floor, part of the wire made an electrical circuit and current continued to flow until it was interrupted.
Because nichrome wire is resistive wire, not all the wire turned luminous.
Trent either dashed for the switch/power source or the current burned through the luminous part of nichrome wire.
This demonstrates the danger of using this type of supply on a grounded surface, in this case the concrete floor of his garage.
His garage is supposed to have a ground fault interrupt outlet.
I did not notice or see if that is the case from the video.
Looking on the left side of my sketch, notice that the Neutral connection has no electrical potential between it and the Ground connection.
If the wiring of the 'supply' was proper (black wire to black, white wire to white), the sketch would explain the situation prior to the failure.
How can Trent prevent this in the future and live to enjoy old age?
I happen to be assembling a foam cutter supply.
One site I was reading discussed that if the foam is vaporizing (a.k.a. smoking - causing gases), the wire is too hot.
This also seems to be the case here - thus the fans to move the fumes away.
The Raptor looks like it will be a fun project.
Let us help Trent work safer.
By looking at the video of his 'power supply' I made a sketch of what I suspect happend.
The sketch is attached.
Trent later says that the fishing line broke. When it broke, the nichrome wire, which has electric potential and not just temperature, touched the concrete he was working on.
Once on the floor, part of the wire made an electrical circuit and current continued to flow until it was interrupted.
Because nichrome wire is resistive wire, not all the wire turned luminous.
Trent either dashed for the switch/power source or the current burned through the luminous part of nichrome wire.
This demonstrates the danger of using this type of supply on a grounded surface, in this case the concrete floor of his garage.
His garage is supposed to have a ground fault interrupt outlet.
I did not notice or see if that is the case from the video.
Looking on the left side of my sketch, notice that the Neutral connection has no electrical potential between it and the Ground connection.
If the wiring of the 'supply' was proper (black wire to black, white wire to white), the sketch would explain the situation prior to the failure.
How can Trent prevent this in the future and live to enjoy old age?
- Use an insulated, fused, proper power supply (I will help you with this)
- Insulate the entire system from the garage floor with something - wood, plastic, cloth, any non-conductive material
- Stay away from power sources that could supply 15 amps- in short, abandon this 'supply'
I happen to be assembling a foam cutter supply.
One site I was reading discussed that if the foam is vaporizing (a.k.a. smoking - causing gases), the wire is too hot.
This also seems to be the case here - thus the fans to move the fumes away.
The Raptor looks like it will be a fun project.
Let us help Trent work safer.
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