Wiring a DPDT Toggle

[cefinkjr]

DCC or no, there are still occasions when we need to wire a DPDT toggle so that it reverses the polarity of the circuit; e.g., stall type switch motors in yards. Wiring the "X" on those buggers -- particularly the miniatures or sub-miniatures -- can be a real pain. But I hit on a technique this morning that makes it a bit easier.

1. Trim a piece of wire so that it will fit between the terminals on opposite corners with enough extra to allow you to clinch the wire through the solder terminals. If you're not a belt-and-suspenders type person, don't worry about the extra.

2. Strip as little insulation as you can from one end of the wire.

3. Strip enough insulation from the other end so that the remaining insulation will not quite fill the distance between the backs of the solder lugs.

4. Slip the longer exposed end into one solder lug and line up the shorter with the opposite lug.

5. Use your needle nosed pliers, Xacto knife, fingernails, or whatever to push, pull, and coax the insulation to be more or less centered on the wire with one end of the wire sticking out through each solder lug. This is a little more difficult for the second wire in the "X" because it has to bend over the first . It can be done though.

6. Clinch the wire aroung the solder lugs or, if you prefer, solder them right now. Voila!! [^]

I use 20 gauge solid wire for this sort of thing and this technique has cut in half the time needed for this task. The finished product is much neater too and the wires are not as mangled. I doubt it would work for stranded wire though.

This is such a neat technique, it ought to be taught in Model Railroad Wiring 101. Maybe it is and I slept through that part of the course. Or maybe it's just common sense and I'm a slow learner. Whatever. I discovered it after wiring what seems like a bazillion DPDTs but maybe somebody else will see this post and save themselves some time.

Chuck

[cwclark]

Or...nix the solder type lugs and use the DP/DT type with screw lugs...All that soldering gives me a headache!...all i do is bend the wire in a C shape...wrap it around the screw and tighten ....very simple!...The other Chuck[:D]

[rrinker]

Yeah but then you have to use those BIG switches - fine for block toggles but overkill for low current things like Tortoises.
Not sure when I hit on it, but I've been doing the X wiring that way for a long time now. Another useful hint - one of those good quality wire strippers that grabs the wire and strips it with one squeeze is probably the best tool I bought in a long time. I'm pretty darn good at stripping wire with a wire cutter and NOT nicking the conductor, but this tool is the nuts. Goes all the way down to #20 wire so it works for my feeders as well as #12 bus wire.

--Randy

[cefinkjr]

I thought somebody would surely have thought of this technique before. Why didn't I hear about it BEFORE I wired a bazillion DPDTs the hard way?!? [:p] Oh well, live and learn.

Yeah, I used a friend's high quality strippers before Christmas and they are great. Even I have trouble screwing up that little task with that tool. (Note I said that I have trouble screwing it up; I didn't say I couldn't.) A magnifier with built in headlights is in my budget before strippers though.

Chuck

[cwclark]

QUOTE: Originally posted by rrinker

Yeah but then you have to use those BIG switches - fine for block toggles but overkill for low current things like Tortoises.

may be overkill for some people, but if you have terrible eye sight like mine they're great!...I can see those big toggles and their positions as far as 10 ft. away from the control panel through my coke bottle glass spectacles......i've also found that those micro switches break more often than the super big industrial kind do....all my tortoises are wired to these types of DP/DT's...I just build big control panels and they fit perfectly...Chuck

[trollw]

One other option is to use heatshrink tubing to insulate the wires going across the switch to form the ‘x’. Using a piece of 20 ga bus wire, feed the end through the switch lug, tilt it up and slide on a piece of heatshrink cut to be slightly shorter than the distance to the other lug, and slide the buss wire into the other lug. Use needle nose pliers to bend the free end around the lug and cut off the excess. On the other end, use the needle nose pliers to bend the bus wire around the lug but don’t cut it off yet. Solder the wires to the lugs. Now take the end of the wire sticking out from the lug and bend it around the end of your needle nose pliers (leaving a loop a short distance away from the lug). Your wire(s) from the supply now connect to the wire loops and the wires to the item being controlled connect to the open lugs of the switch. By the way, for electrical connections, ALWAYS bend the wire over on the item being soldered or crimp it around the lug – the solder should NEVER be what is physically holding the items together – the parts should not come apart prior to soldering. The only departure from this is when soldering the feeders to the sides of the rails – HOWEVER, this is an exception that is forced by aesthetics and still is not a good, electrical soldering practice (just ask the folks who have spent hours tracking down a dead section of track only to find that the joint that looked good was actually a cold solder joint that had cracked between the rail and the wire but didn’t physically move away from the rail because the ballast and scenery was holding it in place).

[Leon Silverman]

Randy:
Were you , by any chance referring to those strippers that are advertised on TV that usually come with a cold solderer? I tried to use it to strip the insulation from two 12-guage wires and it self-destructed (actually, it came apart in my hand).

[rrinker]

Nope, I got mine at Home Depot, and they weren't cheap. Quite a hefty tool actually. I forget the brand, but they are in the electrical section where they have the crimp connectors and crimpers, as well as the overpriced multimeters. I say overpriced multimeters because that cheapy $15 one they have, I got the exact same thing elsewhere for $5.

--Randy

[cefinkjr]

QUOTE: Originally posted by trollw

One other option is to use heat shrink tubing to insulate the wires going across the switch to form the ‘x’.

[^] [^] I like it !! Don't have any heat shrink tubing but I understand and like the concept. [^] [^]

QUOTE: Originally posted by trollw

... take the end of the wire sticking out from the lug and bend it around the end of your needle nose pliers (leaving a loop a short distance away from the lug). Your wire(s) from the supply now connect to the wire loops and the wires to the item being controlled connect to the open lugs of the switch.

[^] [^] I like this too. This would eliminate the problems I've been having with getting two wires through the holes in the solder lugs on the toggles we're using. Of course, I've now wired all of the panels I'm likely to have to wire for some time so this idea will just have to go in the memory bank. Unfortunately, my memory bank is something like a sieve so you may see me asking a question in the future about how to do this. [:p] [D)]

QUOTE: Originally posted by trollw

... By the way, for electrical connections, ALWAYS bend the wire over on the item being soldered or crimp it around the lug – the solder should NEVER be what is physically holding the items together – the parts should not come apart prior to soldering.

[bow] Amen, Brother! This is what I meant in my original post about being a belt and suspenders kind of guy. But there are soldering elitists around who would look down their nose at us -- they NEVER have cold joints and their solder joints NEVER break. They apparently don't know Murphy either. [:)]

But I did know a fellow once who insisted on drilling a blind hole into the bottom of each piece of rail (he hand laid his track) and soldering the feeder into that hole before spiking the rail in place. The result was completely invisible feeders but at what cost?!? I'm not sure he ever finished his track work. I relocated and lost touch with him before he did.

Chuck