My friend is wanting to get a DCC system and he told me that he wants to wire the layout so he can switch between DC and DCC. In other words run decoder equiped locomotives then turn off the DCC and turn on the DC power packs and run analog locomotives. What do you think???
icmr, sorry cant help with the question all though I know it can be done with a bucket load of wires.
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Hope this helps, have fun & be safe,
Karl.
If done that way - so EITHER DCC power OR DC power is connected to the layout, that’s fine. Mix and match is NOT recommended - where one block might be DCC and the adjacent block DC. Bad Things happen when a loco overruns the block boundary, and it WILL happen.
However, as soon as more than 1 loco is converted to DCC - he won’t ever want to go back.
–Randy
icmr,
It is relatively easy to do, depending upon the size of the layout involved. If it is already in existence and wired for cabs, all he has to do is install the DCC system in place of one of the cabs. Set all the block switches to that cab and run trains. To run DC, just switch over to the DC cab. There are variations, but this is the easiest.
Good luck to you and your friend!
I am the FRIEND, and what I am wanting to do is connect the DCC and DC to the track, and using AC switches turn the DCC off (both wires) and using DC switches (on both wires) turn DC on, then if I want to, turn AC switches on for DCC and using DC switches turn the DC power off. The question is, will AC switches stop the flow of DC power? I know that AC switches should not be used to allow the flow of DC to pass through them, but will AC switches stop DC power when turned off, and will DC switches stop AC power when turned off?
I will be using 2 switches for each wire coming off the power packs. 2 for one wire 2 for the other on DC. 2 for one wire and 2 for the other on DCC (AC). After leaving the power pac, going through the switches, the wire will connect with the other wire from the other pac that has gone from the power pac through the switches and connect with the other wire which will combine two wires into 1 which will go to the tracks. I would use 2 switches on each wire to verify that the wire is not accidentally turned on. I don’t want to mix DC and DCC (AC) power at the same time.
The AC switches would be light switches that can handle 120 volts.
I would appreciatte your help.
Thanks.
You sure don’t need light switches, and you don’t want to use two sets of switches. If you arrange things so that there is one source for power that you wnat to switch between DC and DCC you want to use one switch to do the job, but you want a double pole double throw switch, probably with a center off position. In one position the DC will be passed to the track, in the other the DCC. That way there is no possibility for getting both at the same time, and there is no seqence of switches to remember to throw, or to accidentally get thrown wrong.
I wired a 20x40 foot HO scale club layout the way you are talking about. One central power supply is used for both types of control. A double-pole, double-throw toggle switch is used to change over from DC to DCC operation, and vice versa.
The main difference is that our club layout uses Cooler Crawler transistorized throttles for DC block control instead of individual power packs, so throwing the toggle switch to the DCC setting totally shuts off power to the DC throttles, and setting the toggle to DC completely shuts off power to the DCC boosters.
In order to do this with standard MRC power packs, the output from the power pack(s) and DCC booster(s) would need to be wired through the toggle switch, and you would need a different type of toggle if you had more than one power pack or power booster.
There’s no reason to use standard household light switches for this type of control unless you already have a lot of them available.
There’s no reason EVER to use standard household switches or especially plugs for anything but mains voltage. Don’t ever mix them up and then you won’t ever accidentally connect low-voltage to mains or start fiddling with mains thinking it is low voltage.
I’m not sure, is that what you mean by “AC switches”? A switch is a switch is a switch: it turns power on and off, regardless of AC or DC or voltage. A switch is rated for voltage, so you should never use it for higher voltage than that: a 12V switch should only be used for 12V, AC or DC. A 110V switch can be used for 12V or 110V or any other voltage less than 110V, AC or DC, but shouldn’t be used because of the safety reason above. But a switch is not rated for AC or DC, it works for either.
Why not just run the DC loco at address 0? After the DCC is hooked up and running you’re favorite locos will have decoders it them.
I went through this same frustration when I was thinking about DCC.
This also happens to Brides and Grooms just before a wedding.
Don’t misinterpret AC and DC rating on switches, these are strictly an amperage maximum under either AC or DC. A switch is either on or off and does not care whether the electricity is alternating or direct. When people are telling you a double pole double throw switch will allow you to select either your DC power pack or your DCC system to output to your layouts blocks. The best recommendation above is wire your DCC into your current layout as if it is one of several selectable cabs in a given block. The biggest problem that you must be aware of and prevent was addressed by rriker, don’t allow a DCC controlled loco to bridge over a gap onto a DC cab block. DCC will play havoc with your DC power packs and may also damage your DCC power station and controllers and on board decoders.
Will
I think someone up above said not to use light switches to control AC power from the DCC power pack because I could mix it up with 110volt House wire. Well, I can assure you that all of the layout wiring is totally separate of any 110 volt wire. Someone told me to use Christmas lights to light up buildings and I said I would not do that because that involves 110 volts, and I don’t want anything above about 25 volts on my layout. The DC switches I was going to use are the small black and silver DC switches, the AC switches are just regular light switches rated at 110 volts maximum but the DCC (AC) will only use maybe 25 volts or something like that. I think in order to solve this issue I’m going to talk to my Uncle Mike and show him what I’m trying to do. He’s an electrical engineer.
He’s an electrical engineer.
So is at least one (and I suspect more than that) of the people here. The point I am makingis that by using a DPDT you make it IMPOSSIBLE (well, very, very unlikely) to get DC and DCC signals on the track at the same time, which would be a VERY BAD THING. You can do it by block, but then the possibility of a connection being made between blocks (say by at train that doesn’t stop in time) ruining everything. Also, if you do it by blocks, you cannot have a common rail, in other words, both rails have to be gapped. Don’t get hung up on the AC/DC thing, there is no relevance as far as the switches are concerned. The switches just nned to handle the max current you can supply, probably 5 amps or so.
It’s great to keep mains AC away from the layout. I see some articles in MR aor RMC and posts here that worry me, as peopole get pretty cavalier about wiring power outlets and lighting under the layout themselves. And I see designs for throttles etc that have a mains transformer sitting next to the throttle circuitry. I build my own throttles sometimes, and the mains is in a screwed-shut metal box way separate from any other circuitry. Same for the supply to my Digitrax Zephyr. So good on you.
So you could use AC light switches and feel pretty comfortable that noone is going to get confused. (Some people have used AC power plugs and sockets for low-voltage wiring - now that’s really dumb as it would be so easy to plug a mains extension cord into something). Agree with all that.
But the other point coming up here is that you don’t need to use mains light switches to control low-voltage AC - you can use the same smaller cheaper switches that you use for DC.
Having said all that, I have saved away a couple of old round light switches with the metal toggle on them because I like the chunky bakelite base and the “thunk” they make: they would look great on a panel trying to look like a vintage railroad panel. So who am I to talk ? [:D]
P.S. I’m an electrical engineer
NSR: Lamps for buildings can run on either AC or DC. You can power your lights in your home on batteries (DC) or standard house 120V. The issue is the “filaments” in the lamps. At work, we were not allowed to have Christmas lights around the office walls, they were afraid of fire I guess. So what many of us did was to hook up a few batteries ( standard “D” cells, and voila, we had our tree lit…no AC. So go ahead and light up your buildings with DC.
Thanks for the help. Yesterday, I tested the configuration that I was going to apply to the DCC and DC power packs. I used my DC power pack and “pretended” like it’s AC ouput was the DCC. I wired it up the way I mentioned and using a voltage tester, everything worked the way I wanted to. The light switches worked for the AC and the DC switches worked for the DC. Also, thank you robengland for your reply, I really understood thoroughly everything you said, and once again I agree, it is a good idea to keep 110 volt wire away from your low voltage wires. The only 110 voltage wire on my layout is the cord that the power pac uses to plug into an outlet. Once again, my configuration worked and thanks for the replys.
NSR: also watch out for the warning about a loco bridging a gap between a DC block and a DCC block - stuff can get fried.
One way around this is to rig a switch that just changes the WHOLE layout from DC to DCC, BEFORE connecting to any block switches (which just serve to select DC cabs and/or provide on/off function). This is easy or tricky depending on how many DC cabs you have