Model Railway Forum

I've noticed a lot recently both on forums and on YouTube, that a lot of people no longer twist their bus wires. Is this a thing of the past or is it still recommended?

I’ve never done it and never had an issue.
Once twisted surely it becomes an issue to add extra droppers if needed?

Actually Steve, you were one of the ones I noticed didn't do it. I've done in the past, but probably won't bother in the future.

The bus is connected to the rails and they aren’t twisted.

If your bus wires are in close proximity to other wiring then twisting the bus wires can prevent interference between the bus wires and the other wires. Telephone cables, for example, have twist in the individual pairs of wires to prevent interference and overhearing.

Another recommendation is to keep the bus wires apart from each other and other wires.

The large current pulse that happens when solenoid point motors operate may be the most likely source of interference on a layout.

Telephone wire the type that was/is used for extensions, called 4 wire, had no twist, four individual wires.

I agree it is best to keep the bus away from other wires but that is not always easy.

Solenoid point motors are usually very close to the track which is in itself just an extension of the bus.

Some twist, some don’t, a matter of choice. I think it is better just to keep the two wires well apart, makes it a lot easier to attach droppers.

I'm not referring to internal cable but underground cable that used to contain up to about 800 pairs or more and ran for a number of miles. Even overhead open wire trunk lines would have twists in them.

I'm not saying that twists in bus wires are necessary but hopefully helping people to understand why twists might help.

With you now Rog. When I did my GPO apprenticeship (my dad was a cable jointer) cables were joined to a set plan, not colour to colour, so each pair of wires sort of spiralled along the lengths of cable but matched up at each end which of course were often many miles apart. So a blue wire could be joined to a red then that to brown then green and finally blue again in a simplified form.

Mr Bones wrote: ↑Sun Aug 15, 2021 8:08 pm I've noticed a lot recently both on forums and on YouTube, that a lot of people no longer twist their bus wires. Is this a thing of the past or is it still recommended?

On long DCC Bus pair wire runs twisting will help overcome any induced interference. But on the average UK layout (up to around 18 feet long) keeping the two DCC bus wire about 50mm or more away form other wiring will ensure all is OK. However, all that said, there is no reason why around 8 to 10 twists per Mtr of the DCC bus wire wont hurt anyway!

Walkingthedog wrote: ↑Sun Aug 15, 2021 10:07 pm Telephone wire the type that was/is used for extensions, called 4 wire, had no twist, four individual wires.......................

Not true Brian, only last week I bought a couple of meters of telephone wire from Bitsbox. I use it a lot in my electronic projects. I stripped it only yesterday.

It had Orange/White twisted with White/Orange and Blue/White twisted with White/Blue. then the two twisted pairs were loosley twisted with each other all in a plastic white sheaf.