Suggestions for Wiring Accessories

I would use 18 or 20, whichever you have on hand.

If you just have lights, probably 22 ga would be adequate.  If motors are involved, 20 or 18 as Denny recommended.  If it draws a fair amount of power, like a 282 crane with magnet, 18 would be better.

 

It also depends upon how far you are running.  If the accessory is close to the terminal strip, wire size will be less important.

 

What size wire feeds the terminal strip?

Dale, I use 16 guage from transformer to terminal block. 

I would use 22 stranded.  It's the best workable size for what you have to do.  It will work well to connect to the very thin wires from the lights and is big enough to work well in a terminal strip, wrapped or in a U connector.  Use your 18 for any long runs to an accessory that may need more juice.   

That'll be fine .The wire they supply with the buildings is good enough if you can use it for a pig tail to drop down to your 16 gauge wire . I usually come up short so if you keep a little 18 gauge wire around handy it makes it nice. You can usually get it at Lowes or the auto parts store.

David

DPC, I use 18 guage to track lock on's and 16 guage just from the transformer to my terminal blocks.  Others on here have suggested 20 to 22 stranded for accessories.  What do you think?

 

I suspect that for almost any accessory that #20 or @22 is plenty.  Now, if you're daisy-chaining ten of them, heavier wire might be called for.

How about just making sure that you don't go smaller than that provided by the manufacturer of the accessory. You can always match or go larger.

The only thing that I would do if it's my layout is to make sure that the fuse is sized appropriately for the wire size your going to use.  But I believe you know this already.  That way if you do end up drawing too much current  because of the quantity of accessories or increased current that might occur as a result of a short or excess current draw the fuse would protect the wiring (if it's too small) from overheating.