DCC and DC . What switch

[jmc1]

Hello all

My layout, under construction, has DCC and DC inputs.  I wish to keep both options for my older locos, but what sort of switch should I use to change from DCC to DC. 

Thanks

[Mick Bonwick]

Double pole double throw - DPDT.

 

Centre off.

Edited May 18, 2020 by Mick Bonwick
Edited to agree with kevinlms about the centre off facility. Thanks, Kevin.

[kevinlms]

11 hours ago, Mick Bonwick said:

Double pole double throw - DPDT.

Probably best with centre off.

[mkrob]

I think the biggest problem running dc & dcc on the same layout, is remembering to switch from one to the other,especially when you are an oldie like me with a goldfish memory LOL.  Bearing in mind that if you put a dc loco on dcc track it could damage the motor. You could use a different connector for dc & dcc to input the track, so only one or the other is connected at one time. Taking all your motive power off the layout may be best when you have finished playing trains, just to avoid any mishaps!

Using these type of connectors could be the answer, clearly marked which is which.

  https://cpc.farnell.com/camdenboss/ctsn433-12mf/10a-terminal-strip/dp/CN00144

Edited May 18, 2020 by mkrob

[F-UnitMad]

I just wouldn't mix the two systems on one layout, either with switches or even seperate connections. Because the day WILL come, when you decide to run your DCC stuff, switch the layout on, wonder what that strange whining noise is, and since when was one of your old DC locos fitted with smoke, and OH ☆@#€!!!!   

[jmc1]

Thanks for the replies and I will pursue the DPDT centre off idea and be very careful.....

[SRman]

If you place a DC-only loco on the tracks while switched to DCC, you'll hear the buzzing immediately. It shouldn't destroy the motor straight away, so there is a little leeway here.

For my lower level tracks (the first circuits I laid down), I wanted that ability too, but being double tracked with station loops as well, I added isolating sections and switches as well, so DCC locos and units could remain on the tracks without taking off as soon as the DC controller was turned on.

Being double tracked and wanting to use independent DC controllers (an old H&M Duette), I needed to be able to switch the tracks to each side of the Duette but to the one command station for DCC. I ended up using a rotary multi-pole switch, with three settings available: DC, Neutral, DCC. It took me a while to work out the wiring for this, but it does work and gives me exactly what I wanted.

For most people this is unnecessarily complicated, and th DPDT centre off switch is the easiest and best way to go.

[MartynJPearson]

You could consider a rotary switch rather than a toggle switch, that might be safer from accidental knocking.

 

IIRC they come in a form that has 12 outputs, so single pole 12 way, double pole 6 way, 3 pole 4 way etc, so you can have a number of "centre off" positions too to avoid accidents.

 

Venturing slightly off topic, but I used a similar arrangement on a siding to switch it between normal operation and a programming track, going for the 4 pole 3 way option. Two of the poles were for the end of the siding, designated as the programming track, the other two being a buffer zone between the main and programming track. The three switch positions were Main - Off - Programming, main energising both sections of track, off killing both, and programming connecting only the programming track to the programming output of the controller, leaving the buffer zone unpowered meaning there would be no issues with a loco bridging both main and programming sections.

[JimFin]

1 hour ago, jmc1 said:

Thanks for the replies and I will pursue the DPDT centre off idea and be very careful.....

Since you are at the design stage, run pairs of wires from each side of the DPDT to lights above your controllers so that there is a visual indication above each as to which is live.