DCC Dropper Wires for 7mm track in the Garden.

[CME & Bottlewasher]

Hi All,

I am trying to plan for supplying DCC to the garden section of Down Ampney - although RC is not out of the picture yet and I may operate a hybrid of the two systems.

I hope to fit a BUS rated up to 10 amp.

I was to use some ex-T&E copper - single strand - for the droppers (from the rail to the BUS) and I have been recently told that such may be too brittle in the long run (in terms of 'movement' in outdoor conditions etc)......I know that we have discussed similar before, yet 'current wisdom' seems to have moved on .

It has been suggested that I use either 7/0.2 or 16/0.2 cable (which is 'Equipment Cable') the only issue I have is that I cannot fathom what the amperage is for these stranded cables and I have come across 3 amp, 5 amp and 1.5 amp being mentioned

The BUS will cope with 10 amp and to start with the Booster/Command Station is 5amp and
as such the dropper wires will only have to cope with passing amps, yet I am well and truly confused now

Thanks in anticipation.

CME

 

[ZiderHead]

7/0.2 is waaaay too weedy, and 16/0.2 isnt really up to it either. 32/0.2 would be ok if you want to use stranded although weatherproof insulation might get expensive. If you're not going to bother with twisted pair cable why not just use solid core mains installation cable? Its tough and cheap as chips

 

[CME & Bottlewasher]

7/0.2 is waaaay too weedy, and 16/0.2 isnt really up to it either. 32/0.2 would be ok if you want to use stranded although weatherproof insulation might get expensive. If you're not going to bother with twisted pair cable why not just use solid core mains installation cable? Its tough and cheap as chips

Hi Jon,

I was pondering that too.

The copper (single strand) whilst being 'brittle' (according to the experts) would have been, IMHO, up to the task - hence my confusion and would come from mains cable that I have to hand......

I suppose that the other fella recommended stranded cable so as to help with any 'movement', yet if the baseboards move that much I shall be up the proverbial creek without a proverbial paddle The boards are pretty solid - now - and I hope that they wont move at all!

Interesting to hear that you have the same thoughts as me

Thanks.

ATVB

CME

 

[ZiderHead]

Just put in S-shaped service loops where appropriate and that will cover the movement (in both the jacketed sections and the unjacketed single ends), plus it will leave some spare length if you need to reterminate them later.

I'm a fan of mains cable - its lots of copper for hardly any money and use stranded mains cable for my speaker cables, and have used it for wiring up monitors in multi-million £ recording studios too

 

[CME & Bottlewasher]

Just put in S-shaped service loops where appropriate and that will cover the movement (in both the jacketed sections and the unjacketed single ends), plus it will leave some spare length if you need to reterminate them later.

I'm a fan of mains cable - its lots of copper for hardly any money and use stranded mains cable for my speaker cables, and have used it for wiring up monitors in multi-million £ recording studios too

Hi Jon,

Thanks - that is a good idea.

I shall have to make 'em 'S' shapedish anyway so as to solder them to the track and BUS fairly neatly.

That's great advice - as you say it is a cheaper way to buy cable and we have some to hand anyway.

Keep rockin

ATVB

CME

 

[JimG]

It has been suggested that I use either 7/0.2 or 16/0.2 cable (which is 'Equipment Cable') the only issue I have is that I cannot fathom what the amperage is for these stranded cables and I have come across 3 amp, 5 amp and 1.5 amp being mentioned

Here's a web page quoting amperages and multi-strand cable details.

http://www.electricalcarservices.com/Cable/Single-Cable-__c-p-0-0-168-169.aspx

This is for auto cable which I would use if you want a cable to withstand vibration and movement. For short droppers you would only be worried by the amperage but if you were going to run long lengths as feeders, you might be more interested in the resistance of the wire so that you don't get voltage drop or poor short circuit identification with DCC.

Jim.

 

[CME & Bottlewasher]

Here's a web page quoting amperages and multi-strand cable details.

http://www.electricalcarservices.com/Cable/Single-Cable-__c-p-0-0-168-169.aspx

This is for auto cable which I would use if you want a cable to withstand vibration and movement. For short droppers you would only be worried by the amperage but if you were going to run long lengths as feeders, you might be more interested in the resistance of the wire so that you don't get voltage drop or poor short circuit identification with DCC.

Jim.

Hi Jim,

Many thanks - I will gen up.

Evidently copper has a lot lower resistance than NS (Rail) so hopefully that will be okay as far as signal and voltage drop etc is concerned As I am using a copper BUS with copper Droppers all should be well - fingers crossed

Kind regards,

CME

 

[Simon]

I have used twin and earth for the "bus" on my line, running the feeds to the rails with multistrand wire with the "flexibility issue" in mind.

So long as you don't use bell wire or something tiny then I wouldn't worry about the resistance values as the droppers are only short lengths and the r in resistance will equal the resistivity of the wire multiplied by the length used, and will therefore feature but little in the overall circuit resistance value (That was a "Grandmother sucks your eggs" public service announcement)

So far the only failure that I'm aware of is where I soldered some brass strip across the underside of the crossing/wing rail assembly. This failed in the first year out there.

The best advice I can offer is to get out there and do it - better to be repairing an imperfect installation than dreaming about a perfect one

Simon

 

[CME & Bottlewasher]

I have used twin and earth for the "bus" on my line, running the feeds to the rails with multistrand wire with the "flexibility issue" in mind.

So long as you don't use bell wire or something tiny then I wouldn't worry about the resistance values as the droppers are only short lengths and the r in resistance will equal the resistivity of the wire multiplied by the length used, and will therefore feature but little in the overall circuit resistance value (That was a "Grandmother sucks your eggs" public service announcement)

So far the only failure that I'm aware of is where I soldered some brass strip across the underside of the crossing/wing rail assembly. This failed in the first year out there.

The best advice I can offer is to get out there and do it - better to be repairing an imperfect installation than dreaming about a perfect one

Simon

Hi Simon,

Lots of wisdom there mate - we all need a reminder of the 'granny sucks eggs' issues from time to time.

I was contemplating using brass strip/phosphor bronze strip on one or two areas of the point-work, so thanks for the tip off, I shall go back to wire then .

On the subject of getting out there and doing it, we keep tryin, yet I have come accross some more challenges with the layout this evening (we also have endless issues with anything constructed in the garden as we are on clay )

May I ask - what sort of amps are your locos drawing and what gauge (SWG/AWG) wire did you use for the Droppers?

Thanks.

CME

 

[Simon]

My "worst" loco (so far) draws about an amp.

I don't know what swg I used, but it is nearly all ex mains flex stripped from scrap wires from all sorts of sources.

I am trying the flat bar soldered across the wing rail/crossing again but this time I drilled down into the rail and soldered brass "pegs" in first, then drilled some holes in the strip and after dropping it over the pegs have then soldered it. I am hoping this will be mechanically strong enough to withstand the rigours of different rates of movement in each rail. I have also soldered in doubly redundant wire links in addition, this time using thinner than mains flex wire.

Simon

 

[iploffy]

I use 2.5mm T+E. I am not particularly bothered about the look of the bond so long as it works and have only had 4 fail during the last winter. I intend to ballast the track so that should help to disguise the bonds.

 

[CME & Bottlewasher]

My "worst" loco (so far) draws about an amp.

I don't know what swg I used, but it is nearly all ex mains flex stripped from scrap wires from all sorts of sources.

I am trying the flat bar soldered across the wing rail/crossing again but this time I drilled down into the rail and soldered brass "pegs" in first, then drilled some holes in the strip and after dropping it over the pegs have then soldered it. I am hoping this will be mechanically strong enough to withstand the rigours of different rates of movement in each rail. I have also soldered in doubly redundant wire links in addition, this time using thinner than mains flex wire.

Simon

Hi Simon

Thanks for the info

As it's mains flex that gives me a very good idea of what you have used (and I was planning to use).

Hi Ian,

Thanks for you comments....

....I have recently read that some of the newer solders 'crystalise' when exposed to frost in the garden, I wonder if that's why many joints fail too?

ATVB

CME

 

[iploffy]

I was lucky enough to be able to get lead solder as it is still available for non commercial applications, regarding the amount of joints that failed 4 out of nearly 300 isn't bad at all.
Ian

 

[CME & Bottlewasher]

I was lucky enough to be able to get lead solder as it is still available for non commercial applications, regarding the amount of joints that failed 4 out of nearly 300 isn't bad at all.
Ian

Hi Ian,

I still have some lead solder too

That's a very good failure success rate

CME

 

[ZiderHead]

I bought a reel of Sn62 from RS recently, they still have a massive range of lead solders. I'm not sure where this you cant buy lead solder any more thing came from.

 

[CME & Bottlewasher]

I bought a reel of Sn62 from RS recently, they still have a massive range of lead solders. I'm not sure where this you cant buy lead solder any more thing came from.

Hi Jon ,

I think that it was quickly realised that doing away with lead in all solder/applications wasn't workable, so certain applications can still use leaded solder and others cannot (the categories were explained to me yet I forget all of the detail - but I think for personal use/non resale leaded solder can still be used ie in our model-making).

Having said this the lead-free solder comes to the fore more readily....

ATVB

CME

 

[Simon]

I don't think I have had any solder failures in the garden that weren't due to issues of thermal expansion and contraction and the stresses consequently put on the soldered joint.

I am using the bog standard tinmans lead containing solder, which is still widely available although now at a nicely inflated price, thanks to all the hoo-hah and that naughty Brian Lewis and his "clever" advertising at the time.

The potential movement of a soldered joint due to thermal wotsit as noted above is all you need to worry about in my opinion.

If it were to all go tits up then I'd be rolling out the batteries, but one thing I am emphatically not going to do is fret about it before it happens!

Simon

 

[Phill Dyson]

Where do you buy lead solder from these days at reasonable prices?

 

[ZiderHead]

Generally anything electronic will be cheapest from RS or Farnell, the main industry suppliers, although it can take a while to find what you want because they stock everything ...

http://uk.rs-online.com/
http://uk.farnell.com/

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