Model Railway Forum

Evening All

I am in the process of wiring up a bus wire and droppers. Are there recommended lengths for the dropper flex? The way I am proposing the bus wire layout would mean some of the flex lengths would be longer than others, would this be a problem?

John

Are you taling about several feet or a few inches. In my view it won’t make any difference.

Thank you WTD.

My planned layout may require droppers of no more than 1/2 metre, so it looks okay!!

John

A lot depends on the number of droppers and their wire size!
So, if every piece of track has a dropper pair then you can use 7/0.2mm wire, but try and keep its length to around no more than 300mm (12 Inches).
Where droppers are not frequently installed/spaced then use 16/0.2mm and ideally to no more than 500mm in overall length maximum Bus wire to rail.

A piece of wire is just a piece of wire ?
Actually, no.

I did some research for an electronic project which required some long runs of wire.
So I bought in various cables to test.
I was quite shocked at just how much the different wires varied in resistance per metre.
So for a long run you can get quite a voltage drop with poor wire.

Clearly thickness of wire makes a difference too as it affects resistance per metre length.

The clue is the thickness of wire used in a house power supply. Probably why they don’t use lighting flex on the national grid pylons