Wiring a layout with Cat5 cable

[DaveN]

Hi

Will be starting to build a new layout soon (00) and looking at the possibility of using cat5 cable.

Anyone know if cat5 can handle the 12/16 voltage required by most railway accessories.

Thanks

[gordon s]

Hi

Will be starting to build a new layout soon (00) and looking at the possibility of using cat5 cable.

Anyone know if cat5 can handle the 12/16 voltage required by most railway accessories.

Thanks

 

It's the current rating that is more important and Cat5 is only rated at 0.577A per conductor. I guess it depends on what accessories and how many.

 

I s'pect others will be along soon to give their opinion, but I wouldn't feel comfortable with such a low current rating.

[Coombe Barton]

Some CAT5 is solid core, some is stranded. They're all twisted pair. Stranded is less prone to breakage. However putting normal model accessory currents through either will probably result in a small of burning after a short while.

 

Same as Gordon S I'm not at all comfortable with the idea.

[bertiedog]

Hi

Will be starting to build a new layout soon (00) and looking at the possibility of using cat5 cable.

Anyone know if cat5 can handle the 12/16 voltage required by most railway accessories.

Thanks

 

Assuming multi strand CAT5( there is solid as well), it can handle the 12/16vac/dc voltage OK, but has a current limitation of about .57 ampere per conductor, on the low side, and is about .2 ohms per metre.

 

Under no circumstances use CAT5 as mains cable, no way, ever, at all!!!!

 

Despite the issues on current it is quite usable for loco wiring, but for layout feeds etc it should really be a heavier gauge cable. However if you have access to a large amount for free or low cost, it can be dual wired on each feed etc., doubling capacity.

 

But one very major check is needed, and that is to very closely examine the wire, as a lot of Chinese made CAT 5 is simply not the real thing, they have used copper plated aluminium cable, it is next to useless as it has higher resistance, corrodes, and is poor at high frequencies,(but not an issue here).

 

Carefully sand the wire at the end and look at the metal, it should be copper right through. Just because it appears to solder is not an indication, the plating takes the solder, but it will corrode later on.

 

If the cable has a well known makers brand on it it is probably OK to use as general purpose wire for light loads.

 

Stephen.

[Coombe Barton]

If the able has a well known makers brand on it it is probably OK to use as general purpose wire for light loads.

I'm not trying to be derogatory, but the manner in which the OP asked the question suggests that the judgement about 'light loads' would not be confidently made.

[bertiedog]

I'm not trying to be derogatory, but the manner in which the OP asked the question suggests that the judgement about 'light loads' would not be confidently made.

 

I did say for loco wiring, and dualed, (or more), use if you want, not the loading required for power feeds etc., .5 amp rating would be OK for lighting etc., and jumpers across pointwork etc. It is not suitable for DCC supplies where the current would be far to high.

[noiseboy72]

Aluminium Cat5 cable is fine for higher frequencies due to the skin effect, meaning that high speed data signals travel along the outside of the cable only. It is also lighter and less prone to failure due to oxidisation of poor joints. For model railway DC or 50Hz low voltage AC, I doubt you could measure the difference, even after a few years.

 

I have used Cat 5e Solid UTP for point wiring & lighting without problems. For the DCC backbone, I use heavy duty stranded cable designed for car stereo installations. It is robust and flexible, plus is easy to crimp and solder as required It will carry 20A at 12V.

 

Speaker cable (Thick bell wire) is equally as good, but the clear red and black colouring of the car cable makes wrong connections a little less likely.

[AMJ]

The possible idea I had about wiring with CAT5 is that at the joints between each layout section I would install a row of sockets a patch pannel on each side of the join. Just a standard lead would be needed to connect 1-1 2-2 etc.

 

The Prodigy Advanced DCC uses a CAT5 cable between the controller and main box. I had a problem with the one that came with it at an expo and swapped it for a 3m lead that was in the laptop bag. I'm now using a 5m and this gives me the length without needing to wire in points at the other end of the loft. I have punch down (Crone) tool and crimp tools for ends so wiring is solder free!

 

I use a similar wire for all my wiring and have done so for a while (it's 4 pair telephone cable). I think looking at it that the spec is probably the same as CAT5 and I have run DC track supplies on it (since changed to DCC) and also have 16VAC for points.

 

If in doubt use a pair as a single wire.

[BR60103]

Not for general layout wiring.

The current rating would work for a single small modern loco. Older Triang, Dublo or Wrenn would really tax it as would any double header.

It should work for frog wiring, internal loco wiring, or jumpers from a bus to rails as long as there are lots of other jumpers in the same section.

 

My rule of thumb is that a modern loco may draw 1/2 amp but older ones draw 1 amp or even more.

 

It's eminently suitable for controller wiring on DCC where it will only carry signals, not track power.

[DavidB-AU]

Cat 5 is excellent for track feeds and accessory control such as lighting effects and slow motion point motors.

 

However Cat 5 is not ideal for carrying power over long distances. It might be okay for a small shunting layout but for a room sized layout you are better off using medium to heavy duty (2-2.5mm) figure 8 speaker cable as a track bus and using Cat 5 for short (under 150mm/6") track feeds.

 

Cheers

David

[DaveN]

Thanks all for your replies - appreciated

 

Looks like (as I thought) cat5 has issues - I will not use.

 

As my layout will be 10mx3m - multicore cable makes more sense to keep everything neat and tidy, and rather than going to someone like Maplin to make it up for me, I'm trying to find "oftheshelf" product.

 

Now looking at burglar alarm cable - comes in 4-6-8-12 multi core stranded - and at around £15 per 100m for the 8 core its cheap.

 

Handles upto 60v but I don't know the rating - any idea if this will be suitable (seems ok to me)

[gordon s]

Thanks all for your replies - appreciated

 

Looks like (as I thought) cat5 has issues - I will not use.

 

As my layout will be 10mx3m - multicore cable makes more sense to keep everything neat and tidy, and rather than going to someone like Maplin to make it up for me, I'm trying to find "oftheshelf" product.

 

Now looking at burglar alarm cable - comes in 4-6-8-12 multi core stranded - and at around £15 per 100m for the 8 core its cheap.

 

Handles upto 60v but I don't know the rating - any idea if this will be suitable (seems ok to me)

 

 

Alarm cable is made up of 7/.02 condictors and is rated at 1A. Again on the light side for track power, but will be OK for low power accessory circuits. 16/.02 would be better for dropper connections to a main bus or track power in DC applications.

[Edwin_m]

Just to be clear, the sorts of cable you are considering here will be no good for connections to solenoid point motors. These need at least 24/0.2 or equivalent.

[melmerby]

A long shot:

 

Do you know anybody having a house re-wire, mains 1.0mm would do fine.

Ive just had a re-wire and the old plastic cable is just waiting to used for my layout wiring!

 

Keith

[RedgateModels]

I use Cat5 wires for track droppers. They conveniently come in twisted pairs in blue and brown - matching the colour coding of the bus wires that use domestic ring main cable. I use one pair per rail dropper, so even if one gets broken there's a backup

 

 

It's also free from work

 

 

[bertiedog]

I would still worry about checking it's not copper plate aluminium CAT 5, I had nasty experiences with aluminium cable experiments with the GPO and BICC, corrosion can occur without any trigger, and crimping is the only way to join the stuff, as soldering is un-predictable with aluminium. Look at the problems BT have in Milton Keynes, where aluminium cable was widely used......total disaster.

 

Aluminium has a tough oxide surface, we use it as sand paper!!!, and it needs a strong flux to get solder to alloy, any trace left and it corrodes.

 

The plated aluminium is better, the copper should protect the aluminium, but it depends on the plating quality, and the Chinese cables barely passed tests at first.

 

But to solder to this cable is really asking for trouble, it works, but the flux attacks the plating at the edges of the tinned area, exposing aluminium and it deteriorates rapidly.

 

I would be prepared to use CAT 5 copper on layouts for any use if doubled up, cheap and reliable wire, especially the stranded version.

 

By the way, there is no such thing as separating signals and power in DCC it is all the same connection, a simple pair, and as such has to be a much larger size to allow the power to flow without excessive resistance.

 

The bus bar or power cable is simply in parallel with other wiring, it does not bypass the smaller loop and dropper wiring, or separate up the signal or power.

 

Stephen.

[buffalo]

...

By the way, there is no such thing as separating signals and power in DCC it is all the same connection, a simple pair, and as such has to be a much larger size to allow the power to flow without excessive resistance...

 

I think what was meant here was the difference between the 'signals' between a hand-held controller and the power booster (e.g. Lenz XpressNet), as compared with the 'power' feed from booster to track (standard DCC signal/power).

 

Nick

[bertiedog]

My apologies, I was not getting at the comment by the poster, but commented separately as I had often heard the suggestion from other users that the DCC signals and power are separate in some mysterious way! One commentator suggested that the power bus was an absolute requirement as the track does not carry power.............it all goes via the bus cable.........a sad lack of electrical knowledge.

 

Cat 5 ( especially in pairs), would suit hand held control cables as well as any type.

 

Stephen,

[jamie92208]

Having seen that the layout is goin to be 10m by 3m then the minimum requirement for the layout is 16/0.2 cable which is about £11 per 100m roll from the likes of RS. The main problem on a lyout that size is voltage drop and the bigger the better. Household mains cable is ideal and also use as few joints as possible and try and make long umbilicals rather than taking power through each baseboard in turn.

 

Current carrying capacity is what matters rather than voltage rating.

 

Jamie

[Edwin_m]

By the way, there is no such thing as separating signals and power in DCC it is all the same connection, a simple pair, and as such has to be a much larger size to allow the power to flow without excessive resistance.

 

True, but it is possible to run a separate bus to carry the DCC signal to accessory decoders which are powered from a separate supply. This is a good idea as by fitting a switch or circuit breaker the accessories can still work if the track has shorted, which is handy to re-set that "electrofrog" that has been trailed through when set wrongly.

 

Although it is carried back to the same command station, the accessory bus carries very little current and therefore doesn't need to use thick wire. It would be wise to protect it via a current limiter for the unlikely event of a short on the accessory bus.