DCC Bus

[Daniel S]

Hi everyone

I am going to be contructing a dcc bus. For the bus wire I am going to use 1.5mm T & E cable. For the dropers, I already have some alarm cable which has seven strands in it so I presume it is 7/0.2mm.

Will this be ok for droppers? I have read somwhere that it will be ok for short lengths.... how long?

Thanks.

[Flashbang]

Hi everyone

I am going to be contructing a dcc bus. For the bus wire I am going to use 1.5mm T & E cable. For the dropers, I already have some alarm cable which has seven strands in it so I presume it is 7/0.2mm.

Will this be ok for droppers? I have read somwhere that it will be ok for short lengths.... how long?

Thanks.

Hi
1.5mm2 solid wires as DCC bus will be ok for the layout.
7/0.2mm2 can be used, but the more normally recommended wire size is 16/0.2mm2. If you keep the 7/0.2mm2 wire short, to around no more than 300mm each wire then you should be ok. If you need longer dropper wires consider doubling up the 7/0.2mm.

[Daniel S]

Ok,

How about Bell wire, would that be any better? Because I have quite alot of that. It is just one solid cable.

[m8internet]

I have just started on the DCC wiring for my N gauge layout

For the droppers I am using 7/0.2 at intervals of 60 cm / 2 feet
However I can get away with this due to N gauge

For the BUS I am using 32/0.2

You could use bell wire, but it might not be enough if the current drawn is more then 1A
If your layout is OO gauge, then I would recommend droppers of 16/0.2

So far today I have done 60 solders, rail to droppers, only another 80 to go (and that is just the lower fiddle yard)
All in I have about 1000 solders to complete

[RFS]

The longer the wire, the greater the voltage drop and hence you need a thicker wire. But for droppers of no more than 2-3ft in length then 7/0.2mm is fine. Whereas the bus wire may be carrying current for all the locos running on the layout, a dropper is unlikely to be feeding more than one - two at a push if it's a double-header. As OO guage locos typically take not more than 0.5amp then the thinner wire will do. After all, look at the size of wire on the decoder harness, or the bonding under Peco points for example. These wires can be thin as they are short and only need to power one loco.

[Flashbang]

Ok,

How about Bell wire, would that be any better? Because I have quite alot of that. It is just one solid cable.

Hi
Not recommended at all for DCC operation, its far to thin!

[m8internet]

Ok,

How about Bell wire, would that be any better? Because I have quite alot of that. It is just one solid cable.

Hi
Not recommended at all for DCC operation, its far to thin!

Bell wire would be acceptable for droppers
I've compared some I have to the 7/0.2 I have used and there isn't much between them
The droppers only have to cope with the current drawn by a small number of locos briefly, as they pass over the connected section

[Flashbang]

Droppers perhaps - only just though, its really getting very thin! The recommended dropper wire size is 16/0.2mm (Of course a bit of 5Amp fuse wire will probably work too, but certainly not recommended! )

But bell wire is never suitable for the DCC bus

The thing is to always over engineer - its costs very little extra, if anything, and you will never suffer poor performance and have total peace of mind
Under rating or using a "That I'll do" methodology will eventually lead to problems

[m8internet]

Recommended dropper wire size is 16/0.2mm

I spent some time converting the recommendations from Lenz;wire rated 1.0A and/or 7/0.2 is the equivalent minimum, providing you are using a bus rated to at least 5A
The only other main consideration is the current drawn per motor, which varies by gauge
One final consideration is changing the output voltage, that is again should only be varied by gauge

When using 1.0A or 7/0.2mm droppers, then they should be no more than 6" / 15 cm in length
Mine are 4" / 10 cm, at intervals of 2' / 60cm
I have also checked my decoder specifications and the maximum current is 0.8A (Lenz mini Silver), all the rest are 0.5A

[Daniel S]

Hi

Thanks everybody for you help so far. My dad has got some old red and black 2.5mm2 T & E wire, so i will use that as a bus and I will use the earth as a "Lighting return bus" to simplify the wireing of the lights. I think,I will get some 16/0.2mm wire, since I will need some for my point motors.

(By the way for anybody else interested, I managed to get my R8216 point decoders replaced with the R8247 accessory decoder by honrby, since one of the units was faulty anyway, they now programme and operate perfectly with the PA ).

[Daniel S]

Hi,

Sorry to bother everybodt again .

I have just checked with my dad and the wire he has is 1mm2 household Lighting cable. Will this be ok, or not? If not i will get some of the 2.5mm stuff. Because my 16/0.2mm wire arrived the other day and i have soldered some track feeds. My layout is about 6' by 7'.

Thanks.

[m8internet]

1mm2 household Lighting cable

Really need to know how many strands, but 1mm sounds plenty to me
Most household lighting is capable of taking 12A, so that's more than enough

[locoworks]

1mm2 household Lighting cable

Really need to know how many strands, but 1mm sounds plenty to me
Most household lighting is capable of taking 12A, so that's more than enough

house hold stuff is all ONE strand till you get to 4mm. most lighting circuits are protected by 6 amp breakers these days but i'd use 1.5mm as a minimum just to be sure, but if i was using a 5 or 8 amp system with longer runs i'd use a 2.5mm bus.

[Silver Surfer]

Funny how we all have different opinions and set ups for our layout and what we find acceptable or good in practice.

I'm using 1.5mm stripped out household lighting cable for my bus with 16/0.2 for the droppers to every piece of track - lots of soldering as it's a total run of around 85metres. I was intent on using 2.5 cabling but I found it so awkward and difficult to work with 30 odd metre lengths** of the stuff under the baseboard, I opted for the lesser 1.5mm which is much more user/installer friendly and so far seems perfectly adequate for my needs - I've had 5 loco's running at the same time.

(EDIT: ** I'm aware I could have shorter lengths of bus wire and join them up but I consider breaks in any cable to be potential weaknesses/sources of future problems so avoid them as far as possible.)

Purely for fault finding reasons the bus is divided into three districts (I call them power districts but technically they're not as they are all switched from one 5amp DCC power source- NCE PowerHouse Pro) with each district protected by using a 12v car tail lamp bulb. For connections from the NCE, through the switches and bulbs to the bus districts I use 24/0.2.

For points I'm using a combination of Fulgurex and Tortoise motors from a separate 9v power source (makes 'em run slower and quieter) and for panel LED's and signalling another separate 12v source. For these I use 16/0.2 for the supply/return from source to motor for the power side of things and 7/0.2 for all other leads.

So far everything is working out just fine (fingers crossed and I've a long way to go).

Mike

[Valentascream]

A DCC Bus?

Aha A digital Routemaster or Leyland Titan? LOL