The AM Forum

A trick I use to get a wide copper strap through the floor, while avoiding cutting a slot, is as follows:

I form a row of holes, whose length is the same as the width of the strap, consisting of 8 to 12 holes drilled through the floor, each just barely large enough to pass a #12 or #10 wire.  I cut the strap at the point where I want to pass it through the floor.  I then solder across  the end of the strap a corresponding number of pieces of wire, long enough to feed through the holes and extend down a couple of inches below.  Once the wires are inserted into the holes,  from the underneath side of the floor, I solder the rest of the copper strap to the lengths of wires poking through the floor, and continue on my way.

This does less damage to the floor than sawing a slot, and it is MUCH easier to do, using a simple electric drill. If the strap feedthrough is ever removed, it is a simple matter to plug the small holes with wood filler.