Hello Everyone,
Experiencing learning a new skill, wiring.
Myquestion is in regards to inserting the 20 gauge terminal rail wire into a suitcase clip. I am using Atlas terminal rail joiners.
My bus wire is 14 guauge so I am using a 14-16 gauge suitcase clip.
Questions:
1 - Do I strip the end of the 20 gauge rail joiner wire before inserting it into the suitcase clip or does the suitcase clip break the insulation and create the connection? If I need to strip it how much should I strip?
2 The wire on the Atlas terminal rail joiners is about 15" (didn't get a chance to measure it). How long should I leave this wire for best possible throughput of amps? Does the length matter?
I know the suitcase clip breaks the insulation on the 14 gauge bus wire to make the connection, my question is only about the 20 gauge terminal rail joiner wire.
Tried Googling it and found many Youtube video and I watched MRR Video Plusbut couldn't find a definite answer to these questions.
I'm not confident the connector you hope to use can safely hold wires with the disparities in gauge you quote.
The connectors you call suitcase are designed to displace the insulation themselves when you close them, so,......no.
For the small amperages we are dealing with (5 or less typically, which I expect to be your case...?), you needn't cut them or shorten them. It's really the voltage drop that's your immediate concern when thinking of long thin wires anywhere that DCC signals have to be propagated along their lengths. Then, when a short happens, you do want thicker wires, ideally, but the higher voltage that you first sought to ensure was adequately high also ensures your DCC system quickly and reliably detects those shorts and shuts off current to the output terminals.
I stated that I believe your connectors are not the right kind for the high disparity between gauges of wires you expect them to close over and keep tight. If you strip any insulation on the 20 gauge, you will certainly not get the retention you hope for.
I expect more knowledgeable people to repond soon.
I suggest sticking with the 3-M brand. You can do 14 ga to 20 ga
There are multiple models of suitcase connectors that handle different guages, you want the 905
http://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Scotchlok-Electrical-IDC-905-BULK-Double-Run-or-Tap-Low-Voltage-Automotive-Applications-Red-22-18-AWG-Tap-18-14-AWG-Run-500-per-bag-5000-per-case?N=5002385+3294757559&rt=rud
A lot of people make their own rail joiner connectors. Admitedly it's a bit fiddley but cheaper. You didn't discuss DC vs DCC but DCC likes lots of feeders
Henry
COB Potomac & Northern
Shenandoah Valley
northeast_train_guy_19651 - Do I strip the end of the 20 gauge rail joiner wire before inserting it into the suitcase clip or does the suitcase clip break the insulation and create the connection? If I need to strip it how much should I strip?
suitcase connectors cut through the insulation, no need to strip
but since you have 14-16 gauge suitcase connectors, the 20 gauge feeder wire may be too small
northeast_train_guy_19652 The wire on the Atlas terminal rail joiners is about 15" (didn't get a chance to measure it). How long should I leave this wire for best possible throughput of amps? Does the length matter?
shorter feeders will be less mess under the layout. And yes, shorter is less resistance and less voltage drop, but is less of an issue for short lengths. Bear in mind there are multiple feeders providing current to the rail.
greg - Philadelphia & Reading / Reading
Below is the 3M document relating to the appropriately-sized connectors:
Note that the wire size range FOR THE 905's is appropriate to OP's needs. And that these connectors may not work for all insulation types. I imagine stripping the wires would be slightly beneficial, as it would minimize the slight chance that the insulation would somehow not displace properly.
If there is any doubt about these, it might be a good idea to do a few test pieces. Also, leave enough slack so that you can bypass a failed connector and add a replacement.
Ed
Definitely stick to the 3M brand Scotchlok IDC's. You may see some so-called scotchloks or similar with a price too good to be true. They are much inferior.
Be sure you get the right ones for the wire sizes you are using as advised above. I got different ones (558) for my 16awg bus and 22awg that had the nice feature of dual cutting teeth. I think the 905 may be your only option for marrying 14 & 20.
It is critical to make reliable connection by closing the cover correctly with the proper tool. Most pliers will cause a significantly angular (vs. parallel) jaws closure motion which is not what you want. Do it right. Some folks get by with carefully using typical Channel Locks but most recommend something more like the pricey $75 or so IIRC special tool. I found a Robo Grip $25 set of two at Sears (hurry) where one had curved jaws but one was on target; i.e, with straight jaws and a close to parallel, vertical closure movement. Used carefully I culd get a good, vertical closure motion.
Mt layout is HO DCC and I use 22awg feeders to the rails, no more than 6' apart. I think I read somewhere that 18" is a goal max length (depends on awg) but I allowed a bit more (up to 3') in some instances. I run consisted diesels so 3 diesels may draw 1.5 amps total, not a horrendous load. Your 20awg feeders will carry alot of juice so more than 1' is ok. For DCC one goal is less than 1/2v drop overall (bus plus feeders). Your 20awg at, say, 2 amps takes 25' for a 1/2 volt drop according to a table in the Kalmbach DCC Guide. So a 2.5' feeder would only take 1/10 of your max voltage drop goal. If you have DC, you can be much more liberal.
I'm skeptical of stripping the wires at all at the IDC. The design is "insulation displacement connector". When closed properly, the clamping/cutting tooth inserts enough to cut through the insulation on one side, pinch against the wire itself and also squeeze the other side of the insulation, which has some resilience and an ongoing squeezing force I'd say. If pinching just bare wire, you are creating a much thinner actual diameter which could be thinner than the thinnest insulated diameter of the IDC design. Plus, you lose the second (uncut) side of insulation resiliency force to keep the connection from loosening. A bit of speculation on my part, but I'd stick with the designed approach (insulated and only for designed awg range).
Note that some people steer entirely clear of using IDCs as they can be problematic in some cases; e.g., with vibration such as in cars & boats. That just says to be sure to use the right ones and learn how to properly install (close) them. Make sure the wires are not subject to stress.
Paul
Modeling HO with a transition era UP bent
I questioon if the wires on the Atlas terminal joiners are even #20. They seem much thinner than that. I know that's what they CLAIM they are...
I do urge you to make yoour own. They are SO overpriced it isn't funny. There's nothing too fiddly about it, you make them at the workbench under ideal conditions. Yoou can churn out a few dozen pairs in an hour or less and instead of a few here and there to supply power, you can make nearly every joint a terminal joiner. What you need is a soldering iron of 25-50 watts, some solder, one of those "third hand" tools that has alligator clamps on arms (holds the joiner and the wire while you solder it), a pack of regular rail joiners, and a small spool of wire. Cut short lengths of wire and strip one end (to solder to the joiner) and then start knocking them out. You can even use 2 different colors of wire (I use the #20 'alarm wire' they sell at Home Depot, its a red wire and a white wire loosely twisted in a pair. This matches the red and white bus wires I use, and if you are careful to install the joiners then wiring it up correctly is just a matter of connecting all the red feeders to the red bus and all the white feeders to the white bus.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
mfm37Don't strip the insulation. Doing so would allow the stranded wire conductor in your feeders to displace and may not make a proper connection in the suitcase connector. It would also allow atmosphere to react with the conductor.
The OP did not say he was using stranded wire.
He did say he was using Atlas rail joiner feeders. They have stranded wire on them. But I wouldn't strip solid either.