DCC Bus Wiring Advice

[Blue Day]

 

Hi all. 

 

Be gentle, another newcomer :). So it’s taken me a year to get a layout planned and laid - not permanentply just testing. So now I’m contemplating securing the track and wiring it fully. Also considering powered points in some places. I have the Elite software running on my laptop that seems to work pretty well (apart from trying to build my layout using their software). I’ve read up on bus wiring and I’m confident to give it a go, are there any basic guidelines to this? 

 

Also regarding points. Although I have Elite I’m considering wiring any points / uncouplers the traditional way with independent switches rather than run it all through the laptop. I just think it’d be easier. 

 

Any thoughts? It’s not a massive layout, roughly 8ft x 12ft with an operating well in the middle. 

 

Thanks 

[Chrissaf]

No problem having a mixture of DCC loco control but retaining the point operating motors on an analogue DC control system. But if you do, I make this one recommendation. You want to reserve every mA of current supplied via the Elite for operating and running your locos and trains. So I highly recommend that the analogue point operating system is a completely separate overlay that uses its own dedicated power supply. In other words, do not use the Elite 15 VDC AUX output for operating your points.

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Also I cannot stress enough the advantages and benefits of basing your point operating system around the inclusion of a CDU (Capacitor Discharge Unit). This of course, assumes that you will be using Solenoid type point operating motors and not an alternative point motor operation technology such as servos or slow action stall motors.

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Again, in an analogue point operating solution. I would advise against using Hornby's R044 point operating switch. These are not 100% compatible for use with a CDU.

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Review these previous posts for more information on wiring Solenoid point motors using traditional analogue switches and technology:

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Solenoid point motors used with general purpose non-locking switches (mentioning R044 and PL-26 switches) plus CDU recommendations.

https://www.hornby.com/uk-en/forum/point-motors-19797/?p=1

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better link

https://www.hornby.com/uk-en/forum/layout-points/?p=1

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or this one detailing actual switch types and functions.

https://www.hornby.com/uk-en/forum/point-motor-switches-newbie-sorry#

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best link yet, incorporating parts of the above links

https://www.hornby.com/uk-en/forum/points-25203/?p=1

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Solenoid point motors draw a lot of current and need thick wiring. I would consider 24/0.2mm wiring to be the minimum, but 32/0.2mm wires would be preferred in my opinion [24 or 32 strands of wire each of 0.2mm diameter inside a common sheath of insulation].

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With regard the implementation of a DCC Bus.....a wise choice in my opinion. I would go even further than perhaps you envisaged and put rail droppers on each and every individual track piece, so that the transfer of electrical current from one track piece to another is in no way reliant on the metal rail joiners. In other words, the metal rail joiners are just relegated to performing physical track joining and alignment. A full Bus implementation connected to all track pieces also means that you do not need to fit any Hornby R8232 DCC point clips to the points.

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With specific regard to the DCC Bus. I recommend that only stranded wire cables are used. Solid conductor wiring can be prone to fatigue induced breakages. Breaks can easily occur within the wire insulation sheath, thus they are difficult to spot.

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I would suggest that the droppers are based on 7/0.2mm wire (7 strands of 0.2mm diameter wires inside a PVC sheath) and that the main Bus is based on 32/0.2mm wire. You should try and limit the dropper length to a maximum 300mm. Under baseboard joints between the 7/0.2mm and 32/0.2mm can be made in many different forms. You could use solder tag strips. You could use terminal screw-down strips. You could use crimps. Whatever you feel most comfortable with.

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The droppers however, will need to be soldered to the outside (or underside) of the rails. So some soldering skill will be required. If you are unsure about soldering, have a read of my soldering tutorial. Underside rail soldered wire connections will need to be installed as part of the track laying as a small piece of plastic rail webbing will need to be removed. Outside rail wire soldering can be performed after track laying. The underside rail connections offer greater scope for disguising the wires and/or covering them with ballast so that they don't show.

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However, if you get any rail droppers reversed. You will get an instant 'short circuit'. So whichever termination method you use, I highly recommend that you connect the track droppers one pair at a time and check for a short before moving on to the next one. A crossed dropper after the event will be very time consuming and disruptive to find if not tested for until the layout wiring is complete.

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I would also recommend some form of colour coding is used to identify electrical function. Two colours for the DCC Bus and other colours as required for other circuits such as point operating circuits (Hornby use Black, Red & Green). Then maybe another pair of colours for any 12 volts accessories that you might deploy on the layout. Internal building lighting for example or possibly signals.

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OK, using lots of different colours to identify different things can get expensive when purchasing the wiring. But the benefits of fault finding and layout wiring expansion later outway the additional up front cost.

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TIP: As this is your very first post, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

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See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

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[Blue Day]

Thanks Chris. 

 

I was intending on using a separate power supply for the points and other accessories. I wasn’t aware of the different methods of installing powered points so I’ll give the links a read, thanks. 

[Blue Day]

So I’ve confidently (gulp) ordered a bus wiring kit after reading various sections on it. Fingers crossed. 

 

Now about point motors. I think I’ve got my head around the need for a CDU and the correct switch to use and solenoid motor. However, a question on switches......

Chris mentions using simple toggle switches (on)off(on) type which is also a cheaper option. However if my reading is correct, the toggle returns to the centre OFF position once you’ve used it. So, hope I’m not being stupid here, how do you know which way the points are directed? I thought the switch would remain one end or the other so as to know which direction the points were set?

Also. Can someone recommend a simple power unit to use for the points and possibly other accessories in future (lights perhaps)?

[Chrissaf]

When using bog standard electrical switches aka toggle ones. You have to use a sprung to centre off. Because the current pulse to operate the the solenoid point motor must be just that..... a pulse. Toggle switches that lock over to one side or the other, create a permanent switching condition not a pulse. If the switch is left over on one side or the other. Two things will happen. If you are not using a CDU, then the solenoid coil will burn out. If you are using a CDU, the CDU will fire the point being operated, but won't then recharge for the next point to be operated.

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If you want a switch that can stay over on one side or the other to indicate point position and want it to be compatible with a CDU. Then you can use the PECO PL26 range of switches as I documented in the links in my previous reply.

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The other option you could use [but requires more wiring and a little more skill] is to use a solenoid point motor that has integral changeover contacts. For example a SEEP PM1 or PM4 point motor and then wire the contacts to LEDs [wired in series with a 1,000 ohm (1,000R) current limiting resistor] mounted next to the toggle switch. The LEDs then indicate which way the point is thrown. The power for the LEDs would come from the 12 volt accessory power supply described further below.

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Ideally for the point operation you want a power supply that is either 16 volts AC or 19 volts DC. If you use the CDU, then the power supply can be 1 amp current rated. If you don't use the CDU, then you want a power supply that is 4 amp rated. I suggest, just because they are so cheap. Using a 19 volt DC Laptop switched mode power supply purchased via eBay.

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16 volts AC and 19 volts DC are not really suitable voltages for general layout lighting, and most general purpose accessories are designed on the basis that the user will be using a 12 volt DC power supply.

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So I recommend that the point operating supply be dedicated for that purpose alone and that a second dedicated 12 volt power supply be installed for the general accessory and layout lighting requirements. This time you want a 12 volts supply with plenty of current oomph as once you get the bug and start adding 12 volt accessories the current demand quickly builds up. As an absolute minimum I would suggest a 12 volt 5 amp supply. Again, Laptop supplies from eBay can meet that criteria quite cheaply.

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However, a word of caution. Do not buy the lowest priced power supplies that you find on eBay. Many of them are copies and clones and may not meet valid safety standards. Try to buy from a UK supplier if you can, rather than direct from China. It is worth paying a little extra to be on the safe side.

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This is an example of how it would be wired up using a SEEP PM point motor

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[Blue Day]

Thanks again. Yeh I’ve looked at the Peco switches and the housing and they look a neat (but slightly more expensive) option. 

 

Unless theres another simpler way to identify point position?

[Chrissaf]

If you use SEEP point motors then you are getting the integral contacts virtually for free. The cost of LEDs and resistors is pence. The SEEP motors are cheaper than Hornby R8014 motors as well.

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PS - The positive lead of a standard round LED is the longer one.

[Blue Day]

Hmmmm something to ponder. I’m edging towards the peco switches and somehow just numbering the points to the switch. Seems a lot simpler for someone of limited knowledge of electrics :)

[Flashbang]

Hi

In case you're unaware.... Seep PM1 - PM4 motors are mounted below baseboard and not like the Hornby R8014 motor which is normally directly fitted to the points underside.  A Seep requires extremely exact positioning to get it to work correctly, any miss alignment will result in frequent failure to operate the point in one direction. Next the PM1 or PM4 built in switch is of very poor quality. Just a simple washer being pressed down by a spring onto the printed circuit boards copper tracks to form the switch action.   Hornby don't make a point motor with a built in switch. 

Remember... You MUST use a switch that is of the Momentary contact type.  The power should never be allowed to be feed continually.  If using a CDU the Hornby R044 Black lever is not recommended due to the way its internal switching contacts operate, see further down this section.... https://www.brian-lambert.co.uk/Electrical_Page_2.html#Bookmark4

 

Using the DCC just to run the trains is always the best option IMO. Points and other accessories are powered and operated by totally separate power sources and switches.  Remember to keep these feed wires separate from any DCC feed wires. 

 

If using a CDU consider the Gaugemaster WM-1 or WM-3 power supplies. Though any power source that is able to provide ideally 16 volts AC at around 1.0Amp is OK. Alternativly use a ex laptop power supply (small brick looking PSU) with a rating of around 19 to 21 volts DC  

 

 

Edit to add PSU comment

 

 

 

[Blue Day]

I think I’m gonna stick with the Peco switch idea and a CDU. I’ll look around for some power supply (might have got something anyway in a box somewhere). 

Just to confirm, the point motor to use. The R8243 is the surface mounted one (which I’ll use for track that’s OOV). Which is the equivalent under board motor to use?

Also, while I’m here, is it possible to have 2 sets of points (used for a cross over) operated by one switch?

[Blue Day]

Chris

when I searched for the PL26 switch at my suppliers, it points me to a PL23 which it says ‘matches the PL26 range’. Will this be ok for me to use with the CDU and does the lever on the switch remain one side or other (not central)?

[Blue Day]

Also, can someone please recommend a suitable power supply for my points layout? It’s a minefield out there  😢

[Chrissaf]

Which is the equivalent under board motor to use?

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R8014

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Also, while I’m here, is it possible to have 2 sets of points (used for a cross over) operated by one switch?

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Yes

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When I searched for the PL26 switch at my suppliers, it points me to a PL23 which it says ‘matches the PL26 range’. Will this be ok for me to use with the CDU.

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The 'matching' statement is misleading you. The PL-26 and the PL-23 switches 'are matching' only in as far that they share the same case style and can fit in the same PECO switch housing boxes. No, you cannot use a PL-23 with a CDU.

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The switch functions that the switch performs are completely different. The PL-26 is a 'passing contact' change-over switch. The PL-23 is a change-over contact switch. You cannot use a PL-23 for operating solenoid based points either with or without a CDU. You must use the PL-26 which is specifically designed for that purpose. The PL-26 does not have a central-off position. The switch moves all the way in each direction, but as it is a 'passing contact' switch. The electrical contact is only briefly made (creating a current pulse) as the switch lever passes through its operating arc. The PL-23 switch on the other hand is not a 'passing contact' switch and makes a permanent electrical connection in each direction. If the PL-23 switch is used directly with a solenoid point motor, the point motor will swell and burn-out the coils.

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Also, can someone please recommend a suitable power supply for my points layout? It’s a minefield out there.

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If you are going to use a CDU then you either need a transformer with a 16 volt AC output or a DC Power Supply with a 19 volt DC output. The 19 volt DC power supplies are easier and much cheaper to source as the 'switch mode' power supply does not use a transformer. It is the transformer that is the expensive component. Also, finding a 'cased' transformer is harder as well at a competitive price.

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So, I suggest a 19 volt DC 'Switch Mode' laptop power supply is used. They are cheap and easily obtained and do the job admiringly. I stress, that these should be used with a CDU. The CDU will reduce the electrical stress on the power supply when points are operated.

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Something like this purely as an example.

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The item in my example has a 5.5mm / 2.5mm DC Coax plug connector. if you don't want to cut off the plug and void the Warranty. Then you will need an adapter to convert to wires to suit the input of the CDU.

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Something like this for example.

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Note that these two examples use 2.5mm centre pins on the DC connectors and not the more common 2.1mm pin variety. You need to ensure that whatever product you eventually choose to source, that the DC Coax connectors match. They are using the larger 2.5mm pin because of the higher current rating of the power supply.

[Flashbang]

Hi Blue Day

The Peco PL-23 IS NOT suitable for use with solenoid point motors such as Hornby or the Gaugemaster Seep etc  You MUST use a momentary type of switch such as the Peco PL-26. However a much cheaper option is to use a sprung to centre Off toggle switch. Often referred to as (On)-Off-(On) type where the bracketed (On) cant remain in the On position once the toggle lever is released.  

As for power supplies suitable for solenoid point motors, this will depend on whether or not you use a CDU (Capacitor Discharge Unit) for the operation of the motors. Only one CDU is normally needed for the whole layout.  If you do, then the Gaugemaster PSU I mentioned in my post on page 1 of this topic are ideal.   If you opt not to use a CDU (Not recommended) then you need a power supply that can provide ideally 16 to 18 volts AC at around 1.0Amp or more or 20 - 22 volts DC at 4 to 5 Amps. Often ex laptop PSU are used.   PSU = Power Supply Unit.  Either a direct plug into the wall socket type (Wall Wart) or the 'brick' type used with laptops etc.  

 

Much of what you need to know is available on my my web site

www.brian-lambert.co.uk

[Blue Day]

Thanks to both. Yes I’m using a CDU (already purchased). 

[Blue Day]

Quick question - thought I'd add to this thread than start a new one. 

so I've started (veeerrry slooowly) to solder drop wires to my track. Finding a tad tedious and fiddly but slowly getting the hang of it. 

so, I've read various stuff in points and fixing drop wires but in a bit lost. Do I keep the power clips in the points and / or attach drop wires? 

[Chrissaf]

The whole point of installing a BUS with drop wires is so that the you can do away with the Hornby R8232 DCC point clips. If there is a drop wire pair installed on each side of a point. That is to say one on the track that leads into a point on the common end and further drop wire pairs on both the potential output route tracks. Then that will completely eliminate the need for DCC clips.

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[Blue Day]

Thanks Chris. I kind of thought that but wanted it confirming before I continued