Troubleshooting Aluminum Condutor Circuits

[frizbeedog]

When these circuits have problems (speaking of 10 and 12 gauge lightng and appliance circuits) I generally can trace this down to the termination of devices. Usually I find the problem at the terminal for the "gounded" conductor at the receptacle. General overheating and insulation starting to melt. Rarely do find this on the ungrouded conductor. Thoughts as to why. I have my own opinions and would like some others.

 

[ptonsparky]

Humm, most installers are right handed, most installations are ground down, so ungrounded connection gets torqued a bit better than the grounded, just by virtue of the location on the device. :roll:

 

[wirebender]

MWBC, neutral not pigtailed?

 

[frizbeedog]

more info

more info

The splice for the circuit is usually at the device, and not pigtailed in the circuits I'm reffering to. Athough torque is probably the issue, what else.

 

[stickboy1375]

Most installers probably believe the ungrounded conductors are so to say more important so they pay more attention to how tight they are vs the grounded conductors...

 

[scrooge]

I am not trying to be a s.a. here but I believe its a 50-50 shot at these locations.bh.

 

[quogueelectric]

different coeficient of expansion ??

different coeficient of expansion ??

When these circuits have problems (speaking of 10 and 12 gauge lightng and appliance circuits) I generally can trace this down to the termination of devices. Usually I find the problem at the terminal for the "gounded" conductor at the receptacle. General overheating and insulation starting to melt. Rarely do find this on the ungrouded conductor. Thoughts as to why. I have my own opinions and would like some others.

Most hot (ungrounded) conductors are under a brass or copper colored screw which may be made of a different metal than the white or silvery colored screw the neutrals are under they may be diferent metals and or have a different coeficient of expantion as in the theory of the bimetalic thermostat or motor heater bimetalic trip unit. Now it is my understanding that the actual damage occurs when the screw doesnt expand as quickly as the aluminum causing it to be compressed more and squeeze out the sides a little bit yet when it cools down the aluminum cannot squeeze its self back to a tight connection against the screw so the thinking would be that al has a high coeficient of expantion and a metal whoch has a lesser value of expansion would most likely be the problematic one. That is my best guess. BTW it has been my experience that the al problems are almost always close to the panel as this is where the highest current occurs in the branch. GO GIANTS NICE WIN!!!

 

[frizbeedog]

BTW it has been my experience that the al problems are almost always close to the panel as this is where the highest current occurs in the branch.

That's what I was thinking.

 

[frizbeedog]

Most hot (ungrounded) conductors are under a brass or copper colored screw which may be made of a different metal than the white or silvery colored screw the neutrals are under they may be diferent metals and or have a different coeficient of expantion as in the theory of the bimetalic thermostat or motor heater bimetalic trip unit. Now it is my understanding that the actual damage occurs when the screw doesnt expand as quickly as the aluminum causing it to be compressed more and squeeze out the sides a little bit yet when it cools down the aluminum cannot squeeze its self back to a tight connection against the screw so the thinking would be that al has a high coeficient of expantion and a metal whoch has a lesser value of expansion would most likely be the problematic one. That is my best guess. BTW it has been my experience that the al problems are almost always close to the panel as this is where the highest current occurs in the branch. GO GIANTS NICE WIN!!!

I was leaning toward someting to do with current. Being close to the panel is something to look for. Good point.