Electrical Conductivity Question

[Guest guest]

Greetings All-

I'm setting up my LOR 1602W Controllers for 40 amps, and am using 12FT sections of 12/3 Wire to do this. The problem is, I'm having a heck of a time getting all of that braided 12 ga copper wire into those little slots on the board. Seems like I get the thing in there, and then I notice 3 or 4 little strands sticking out the side. Not the sort of Arc situation I'm looking for. Is there something I can dip those ends into to secure the wires together, like the ones that came from LOR? I know Silver is the best conductor, but I don't have a bunch of silver laying around to melt down. Is lead a good enough conductor of electricity to use for this purpose? I make my own fishing sinkers out of lead and can easily melt this down. I just remember reading somewhere that lead was not that great at conducting electricity. Will this matter?

Or, if the general concensus is to not coat the wires, would it hurt my ability to use 20 amps if I cut off say 5 or 6 of the little strands to get everything to fit?

Thanks

[Guest guest]

This is called "tinning" and in general, is done with solder. Some recommend doing it (to solve the problem you describe), others say you shouldn't. There's actually a current thread on this -- search for "tin" or "tinning"...

Don't go crazy cutting of little strands, but if it's a hair or two, you (or your circuit) won't miss them.

-Tim

[Guest guest]

The circuit certainly will not miss the few threads that are sticking out, but these dangling threads are still dangerous, and yes, you should be removing these threads, no matter what it takes.

It's plain old sloppy electrical work to leave exposed threads, and it is most likely a violation of the National Electric Code (NEC). Remember, you are dealing with high voltage AC here.

It's NEVER a good idea to leave exposed high voltage wire out in the open.

You don't want these exposed threads to short to the conductor next to them. Also, if your finger should somehow come in contact inadvertently on a "brush by" while the power is on, you'll get zapped, or maybe die in worse case.

In cases like this you have to really look ahead into other chain reaction failures that could occur, like you drop a foil gum wrapper and it lands in the box, shorts against an exposed thread, and blows you board and voids your warranty.

Sounds absurd, but then again it sounded absurd to the guys who put oxygen canisters onto ValueJet Flight 592 back in 1996, improperly capped off to prevent discharge during flight. We all know what happened next.

Electrical codes are here to save us from ourselves. Always use universal precautions and protect yourself against the most absurd of failure modes that you think will happen. Be smart and wire it the correct way, and it may even protect you against failure modes you never would have thought of.

It's not as easy to stick your finger onto top of the little screws on the bus strip as it might be to brush up against an energized thread that is sticking up.

The best procedure for you is to tin the end first with a soldering iron. After you tin the end of the wire, if it cannot fit into the opening on the bus strip on the PCB, then you can snip a few threads of to thin it down before you try tinning the next one.

Jeff's Safety Theorem: Safety First Dudes! Everyone Lives.

Follow Up Theorem: If you die, who's gonna put the lights up?

[Guest guest]

For this purpose (semi temporary and easily redone), you can "tin" the ends of your wires before you put them in the terminal clamps on the LOR.

ON a different note: On a permanent connection you should never TIN wires prior to crimping (unless you flow the solder after the crimp) because over time the solder will flow away from the crimp causing a bad connection.