I am re-wiring for a more permanent layout. The main buss wires, including ground loop are 14ga solid, looped and connected at the ends. Feeders to the track are 16ga stranded soldered to the track. Layout is only 4’x7’.
I’m running a conventional PW ZW, and I have a single loop with (3) passing tracks and (4) sidings. I want to switch the passing tracks and sidings, so I can park PW locos, and be able to turn them off to save the smoke units.
I have read the threads on switching the blocks by isolating the hot wires, but is it possible to keep the hot wires connected, and isolate the ground rails, and switch the grounds?
Connect the Ground Buss, isolate the hot. Connect: Hot Buss-Block Switch-Track. (16ga)
or
Connect the Hot Buss, Isolate the ground(s). Connect: Ground Buss-Block Switch-Track. (18ga)
Which is best? Is 18ga too small for ground feeders?
It is easier to switch the hot wire because you need less insulating pins if using tubular track, to insulate the ground or common you must put insulating pins in both outside rails unless using Gargraves track. Also I would not use 18 gauge wire for ground feeders as 18 gauge is a very small size wire and will get hot quickly, try using 14 gauge wire and buy your wire at Lowe’s or Home Depot as Radio Shack gets very expensive for buying wire over ten feet. You could even buy 14-2 with ground(sometimes cheaper than a spool of wire) and use the ground wire for a common, using the black & white wire for hot circuits.
Lowe’s has has copper, stranded in black, red,green,blue and yellow in 100" and 500" rolls. I just bought five 500’ rolls #12 for the shop. In the long run you save money by getting at least 100’ rolls. You can also get 8-9 colors of hookup or, machine tool and appliance, wire at Auto and Industrial Fastener Distributors in 50’ and 100’ rolls and ranging from #10 to #18 and #22.
Greensboro has two such distributors–Automotive Fasteners, Inc. and Piedmont Fasteners, plus Grainger, Inc. Their prices at the “City Counter” are below NAPA,etc. They all sell via the internet.
On a small layout, I see nothing wrong with using 18 gauge wire for hot or ground feeders as long as you have a 5 amp circuit breaker or fuse in the line. Even the 14 gauge buss is overkill unless the layout is much larger. The large wires are not so much to keep from overheating the wires but to prevent voltage drops on long runs.
You can shut off the sidings by disconnecting the common from the outside rails. But here is the problem: If the siding is already shut off when a train enters the siding, the wheels and frames of the cars can carry the current across the gaps. Sooner or later you will see a flash of light as a coupler’s knuckle spring fuses when it momentarily carries the full locomotive current. I would switch the center rail.
You talk about “feeders” and “buss wires”. The bus wires (one “s”) are feeders. I think your “feeders” may be what are called “taps”. In that case, using a few inches of 18 AWG is just fine. The heat generated will be thermally conducted to the larger wire and to the rails, protecting the smaller wire.
I was trying to save some anguish, since the dollar vale here is negligable, wiring the control panel with smaller (more manageable) wire to the block disconnect switches, typically about 5-feet.
Reading another post, it’s better to wire track at 14ga, in case I ever go onto a Legacy system, that requires 18v, and keep the cable rating (14ga for 15A) within the fuse/breaker range, in case of shorts.