Proper gauge wire for Ross uncoupler

@lionelflyer posted:

I'm hooking up a number of Ross Uncouplers and I'm not sure of the proper wire gauge to use.  The wires on the uncouplers themselves are really thin but I can't tell the actual gauge.  I hope to operate them with Lionel #90 Controllers.  Is 24 gauge solid core adequate?

Short answer, maybe if the wires are all very short home runs back to the transformer.

Longer Answer: If the wire lengths were more than a couple of feet, I'd go with at least 18 gauge up to about 20' feet, but that's only if you wire each uncoupler individually.  If you're running a bus wire some distance to power more than one uncoupler (and/or other accessories) and there's also a chance more than one uncoupler or similar accessory can be activated at a time by grandkids/visitors, then either bigger wire or more individually wired circuits would be safer.

Longest Answer: If you really want to use the smallest possible wire, then you'd need to measure the full round trip length of the circuit.  You'd also need to know how much current the Uncoupler draws (roughly a few Amps).  With that information and an assumed voltage of 16 VAC , you can find the recommended wire gauge on a Wire Ampacity Table for either Solid or Stranded wire.  Well, maybe this wasn't the longest answer until I added this sentence to say that even though the answer isn't all that long, finding the solution would take longer.

Hi Steve,

Thank you.  I guess I just don't understand electricity.  The wires that come attached on the Ross uncoupler must be about 32 gauge, although they are quite short.  I wanted to just daisy chain the power between the #90 controllers rather than making a run back to a buss (about 3 feet for each).  This would greatly reduce the amount of wire strung under this area of the table.  There are a total of 9 uncouplers and only one would be activated at a time.  I have no idea of the current draw of the uncoupler.  I can't find it anywhere.  I did note that an Atlas Uncoupler, which I am not using, comes with 20 Gauge wire.

@lionelflyer posted:

I'm hooking up a number of Ross Uncouplers and I'm not sure of the proper wire gauge to use.  The wires on the uncouplers themselves are really thin but I can't tell the actual gauge.  I hope to operate them with Lionel #90 Controllers.  Is 24 gauge solid core adequate?

What's the Ross product number for your uncouplers (so that we can look up the details)?

Mike

It's fine to leave the smaller wires that come with the uncouplers attached to them.  To extend them in the way you describe, using a larger wire gauge like 18 or bigger is recommended.  In other words, run one 18 or 16 gauge to one side of all the #90 controllers from the transformer hot in parallel (daisy chained).  From the other terminal on each #90 controller, either connect the stock Hot Uncoupler wire directly or extend it with 18 gauge.  For the ground/common connections to the transformer, run a 18 or 16 gauge wire that connects to all of the stock uncoupler ground wires together to this one common transformer wire.

The stock wires that come with the uncoupler are rated for short distances.  If you extend the length of the circuit between them and the power source, increasing size of the additional wire length is preferable.

A given wire gauge and type has a constant electrical resistance per foot, with larger wires having a lower resistance.