Are tandem 22 avg wires as good as a 16 awg wire?

No. You’d need 19 gauge wire to get the equivalent current carrying capacity of 16 gauge.

There are also other good reasons NOT to do this unless you have the proper circuit protection on each wire, AND they are configured to trip together.

Parallel feeds are permitted by code but the ampacity of the wires must equal the rating of the larger single conductor. Overcurrent protection must be properly sized and disconnect all energized conductors simultaneously.

In this application, I wouldn't recommend it. I use FT for my Christmas layout and use 16 ga speaker wire. I tuck the wire under the track bed to keep the floor clean.

Mmm, dunno about the resistance/current carrying ability of two 22 gauge feed wires vs. one 16 gauge wire, but I'd say if you are experiencing voltage drop problems with the single feed, you'd probably do better to just replace that wire with the larger gauge, rather than try to add another wire to be secured/hidden. The suggestion to use the FT to cover and hide the wire is IMHO very sound, whether one wire or two.

https://precmfgco.com/wire-gauge-sizes-guide/

Check this link (typical of many if you search something like awg specifications).

Just look at ampacity (max current ) and you will see how different 16 and 22 are.

@hokie71 posted:

https://precmfgco.com/wire-gauge-sizes-guide/

Check this link (typical of many if you search something like awg specifications).

Just look at ampacity (max current ) and you will see how different 16 and 22 are.

. . . and to summarize, the cross-section and current carrying capacity of 22 gauge wire is roughly one-quarter that of 16 gauge (rated at less than an amp!), so it appears you'd need *four* pairs of 22 gauge wire to substitute for a single 16 gauge pair. I think that affirms my earlier suggestion to just replace the current wire with 16 gauge, and be done with it!

@rplst8 posted:

No. You’d need 19 gauge wire to get the equivalent current carrying capacity of 16 gauge.

There are also other good reasons NOT to do this unless you have the proper circuit protection on each wire, AND they are configured to trip together.

I should of looked at the cross sectional area instead of diameter.  Two 22 awg wires have a similar area to a 19 awg wire.  Why would 2 parallel wires connected to the same piece of track and connected back to the same PH180 brick need special circuit protection?  I guess I can solder 16 gauge wires to the tabs under one of the track sections.  Why does Lionel use such a small diameter wire on their FasTrack power terminals?

What about electrically breaking each oval in two using 2 insulated track sections, putting a FasTrack terminal track on either side of one of the insulated sections.  Then run both sets of wires for that loop back to the transformer.  That way all the wires would still be in the same small area of the layout and each terminal track would only be powering half of the loop.

Thanks for help.

@JFC454 posted:

I should of looked at the cross sectional area instead of diameter.  Two 22 awg wires have a similar area to a 19 awg wire.  Why would 2 parallel wires connected to the same piece of track and connected back to the same PH180 brick need special circuit protection?  I guess I can solder 16 gauge wires to the tabs under one of the track sections.  Why does Lionel use such a small diameter wire on their FasTrack power terminals?

What about electrically breaking each oval in two using 2 insulated track sections, putting a FasTrack terminal track on either side of one of the insulated sections.  Then run both sets of wires for that loop back to the transformer.  That way all the wires would still be in the same small area of the layout and each terminal track would only be powering half of the loop.

Well, it's the same arithmetic I stated before: 19 gauge wire is about half the cross section area and current carrying capacity as 16 gauge, so if you want to run two wires that would be equal to 16 gauge, *both* need to be 19 gauge. Or, if you want to keep the original 22 gauge wire (which has one-quarter the capacity), you'd need to add *three* more lengths to equal the performance of 16 gauge . . . or you could skip the 22 (or 19) gauge entirely, and replace the feed with a single 16 gauge wire pair.

As to your second question (and assuming you are only running a single engine on the track loop), I see no need or advantage to doing what you suggest. Isolating the terminal track sections will *reduce* the available power at any point, since all current will have to be drawn through a single terminal track connection, rather than through *both* terminal track connections. In other words, depending on the location of the engine on the loop, the engine would only be able to draw power from one terminal section at any time, rather than from both through the rails connected in both directions. Frankly, I've never seen the terminal track to be the limiting factor in performance, but rather the distance between such connections and the engine on the track (and the quality of connections between the track sections), with the solution being to add more power drops around the loop, rather than create isolated sections.

Adding to my previous comment. I forgot to mention that parallel feed wires need to be the same length as well. Seems obvious but it should be mentioned. They would all terminate under the same screw or track tab so by default they would be protected by the breaker in the transformer.
As Steve said, if you are powering one loop and not creating separate isolated sections, then the second power terminal track can just be added, no need to isolate the two. Place it as far from the first as practical for what you are trying to do on the loop.

Also of note- stranded wire has a higher ampacity rating than solid. This is due to the increased surface area of the multiple strands.

FT has a notch in the plastic ribs under the track to run the wire through. A dab of hot glue will hold them in place. A shot with a heat gun will soften the glue to remove it later.

Check out this thread for some additional suggestions.

One more tip- get a box of mini binder clips. Place one at each joint with the tabs out flat against the bottom of the track. Helps keep the connections tight. Don't ask me how I know......

Don't mind my helper.....

Bob

Maybe the attached will help?

Cute kitty cat by the way!

Rod

Well, maybe we're getting carried away given the stated application!  20 feet of #22 wire will have a resistance of around .33 ohms.  So for a run of ten feet out and back from the transformer, the total length of the circuit is 20 feet.  Let's assume 3 amps of current draw, probably way over what will actually be drawn by two LC locomotives without smoke.

The voltage drop in the power run from the transformer to the track will be less than 1 volt at the full 3 amps, and the power being dissipated by the wire will be less than 3 watts.

I'm all for safety here, but we need to look at the problem at hand.  The single #22 wire would likely suffice, and certainly doubling it up would be more than sufficient, that would be a max voltage drop of .5 volts in the run, assuming ten feet of two conductors.

What John said.  

@gunrunnerjohn posted:

I'm all for safety here, but we need to look at the problem at hand.  The single #22 wire would likely suffice, and certainly doubling it up would be more than sufficient, that would be a max voltage drop of .5 volts in the run, assuming ten feet of two conductors.

All good points, and FWIW I completely agree. My sole caveat would be to emphasize the need for a 5 amp or so fast-acting circuit breaker or fuse on any circuit using such wire, in case of a derailment/short circuit.

I used about the same size wire to power my elevated trolley loop (it was easier to conceal when run from the layout up to the el), only to have smoke from the wire's burning insulation billow from below and above the layout after a trolley derailed! At the time, I was using one throttle circuit on my hefty post-war ZW, and discovered the built-in circuit breaker was only intended to protect the transformer rather than anything else on the layout, and the transformer was more than powerful enough to fry three feet or so of small-gauge wire before the breaker acted! I have since installed 5 amp circuit breakers on all circuits and have not come close to a repeat performance!

I would question the data in that table.  It says that 14 gauge wire is rated at 5.9 amps.  14 gauge wire is standard for houses and it is connected to 15 amp breakers.  Is this a real problem or am I missing something?

Ed

I agree with a good 5A breaker, that seems like a worthwhile safety addition.  I just don't see the rational for going to all the angst of heavy wire for the stated situation.

I note that Lionel uses #24 wire for power and motor leads in most of the later Legacy models, including those with multiple smoke units.   I'd bet money and give you odds that they draw a lot more current than those two LC locomotives.

@Ed Kelly posted:

I would question the data in that table.  It says that 14 gauge wire is rated at 5.9 amps.  14 gauge wire is standard for houses and it is connected to 15 amp breakers.  Is this a real problem or am I missing something?

Ed

I have no clue where you are seeing that. The upper row right below #14 shows rated at max 17 amps and should be fused for 15 amps.

@Ed Kelly posted:

I would question the data in that table.  It says that 14 gauge wire is rated at 5.9 amps.  14 gauge wire is standard for houses and it is connected to 15 amp breakers.  Is this a real problem or am I missing something?

Yeah, I had much the same reaction. If we're referring to the same table, 22 gauge wire (not infrequently used successfully on many layouts for short runs) was rated at less than an amp, and almost any engine will draw that much or more. I suspect whoever built that chart was erring on the conservative side, but I see no reason to question the *relative* capacities of the various gauges.

I think some of those charts are built with specific percentages of voltage drops in mind determining the "rating" of the wire.  When you calculate the required trace widths doing a PCB, you can do tradeoffs between temperature rise, voltage drop, etc. to determine the trace width required for a specific run.  I think similar assumptions are baked into those charts.

At this point I have soldered 2', 16 awg wires to the tabs underneath two 30" FasTrack straights (one for each loop) to replace the 2', 22 awg wires Lionel uses on their Fastrack terminal track.  The two engines draw less than 2 amps combined, but for safety I will put a PR11-0-  3.50 amp Airpax breaker in the line.  If that "buzzes" because the current is getting close to the trip value, I will swap it out for a 5.0 amp Airpax.

I appreciate all the comments that have been made.

@Steve Tyler posted:

Yeah, I had much the same reaction. If we're referring to the same table, 22 gauge wire (not infrequently used successfully on many layouts for short runs) was rated at less than an amp, and almost any engine will draw that much or more. I suspect whoever built that chart was erring on the conservative side, but I see no reason to question the *relative* capacities of the various gauges.

Are you guys looking at the same table I am??

@Rod Stewart posted:

Are you guys looking at the same table I am??

Nope, the one posted earlier in the thread, to which I responded.

OK I get it, never saw that table when I posted mine a few posts above. I thought I was going crazy......

@Rod Stewart posted:

OK I get it, never saw that table when I posted mine a few posts above. I thought I was going crazy......

Well, to be fair, it was just a link that was posted, so it's easy to overlook!

@Steve Tyler posted:

Well, to be fair, it was just a link that was posted, so it's easy to overlook!

You're letting me off the dummy hook easy Steve!

Been doing any singing lately?

@Rod Stewart posted:

Been doing any singing lately?

Nah . . . takes too long to get through makeup!

@Rod Stewart posted:

Been doing any singing lately?

How about you, you have quite a musical touch.

I realize the NEC might be a little overkill for our “toy trains” but remember, circuit protection isn’t for when things are operating normally.

@rplst8 posted:

I realize the NEC might be a little overkill for our “toy trains” but remember, circuit protection isn’t for when things are operating normally.

Well, we also have to sprinkle a little common sense in as well.  As long as the upstream circuit protection is decent, the #22 is more than sufficient for this task.  If you're going to put an old PW-ZW on the other end with no added circuit protection, then I'd be a lot more concerned!

@gunrunnerjohn posted:

If you're going to put an old PW-ZW on the other end with no added circuit protection, then I'd be a lot more concerned!

True that!

@gunrunnerjohn posted:

How about you, you have quite a musical touch.

Haha, not so much!

True story though: I was over to our LHS yesterday chatting with a good friend who works there part time. He said my twin had been in about a month earlier. I looked kind of perplexed I guess (since I don't have a twin brother) and it turns out the guy pictured above was in town for a concert. He of course likes to hit local train shops wherever he is in his spare time.

Rod

@Rod Stewart posted:

Haha, not so much!

True story though: I was over to our LHS yesterday chatting with a good friend who works there part time. He said my twin had been in about a month earlier. I looked kind of perplexed I guess (since I don't have a twin brother) and it turns out the guy pictured above was in town for a concert. He of course likes to hit local train shops wherever he is in his spare time.

Rod

I often wondered if you were “Sir Roderick” and the picture you had as your avatar was to throw us off the scent.

@rplst8 posted:

I often wondered if you were “Sir Roderick” and the picture you had as your avatar was to throw us off the scent.

Did it work?

Seriously, the avatar is the real deal. Thats my mug with the lovely and gracious Doris by my side. I turned 78 last month and when I asked her if I looked 78 she replied: “No but you used to!” What a gal…..

Rod,

When I talk to you on the phone you are a young 78!  I guess the secret petroleum jelly helped you all those years.

Jim

@Rod Stewart posted:

Seriously, the avatar is the real deal. Thats my mug with the lovely and gracious Doris by my side. I turned 78 last month and when I asked her if I looked 78 she replied: “No but you used to!” What a gal…..

Now that is funny!

OMG. So many electrons lost their lives in this, what should have been, a quick discussion.

First, to get the red herrings out of the discussion, there is no electrical code that prohibits the doubling or multipling of LOW VOLTAGE conductors.  The NEC does prohibit the installation, with a few exceptions, of multiple LINE VOLTAGE conductors. In case anyone really needs to know why: if one of the multipled conductors fails, the entire load is then being carried by the remaining conductor, (protected by the larger circuit breaker) which can then overheat, fail and/or cause a fire, etc. See, for reference, Section 310.4.

Now, back to the really simple arithmetic answer, which every one of us needs to remember:

If you double EQUIVALENT conductors, just subtract 3 from the gauge of either wire. The answer is the equivalent wire gauge for the pair of conductors.

Example:  two #14 wires in parallel...the equivalent gauge is 11.  (14 minus 3)

Two #24 gauge wires equals a #21 gauge wire. (24 minus 3)

No cross sections, ampacity charts, hand waving or head scratching needed. Just subtract 3 from the original gauge of one of the (equivalent) pair.

You'll notice that the answer, in each case, is an odd number, and probably a wire size that doesn't exist commercially.  You need to step down one number to get a commercially available gauge. AWG 11 becomes #10, for instance.  AWG 19 is available as a telephone company gauge in subscriber cables.  Two #19's yield an equivalent AWG of 16. This is an exception.

@Arthur P. Bloom posted:

OMG. So many electrons lost their lives in this, what should have been, a quick discussion.

Actually, your answer was overkill.

IMO the problem was a non-issue to start!  The #22 wire was more than sufficient to carry a couple of amps.

https://ogrforum.com/...6#182044000670755676

One good additional suggestion was adding a 5A circuit breaker or fuse to the power feed.

@RSJB18 posted:

... the second power terminal track can just be added, no need to isolate the two. Place it as far from the first as practical for what you are trying to do on the loop.

This would be the right answer for this application.  I just spread 2, 3, or 4 power feeds around the layout for floor or temporary display, using the factory 22 gauge wire pigtails.

Just because it's low voltage, and may or may not be covered by the NEC, it doesn't mean you can't melt a wire and start a fire.

All that matters is that that you protect the wire properly. And in my professional opinion, if you double up wires to get a higher current carrying capacity, you need to really size your circuit breaker or fuses properly.

Scenario for consideration...

You have two 20 gauge wires with a rated ampacity of 11A for chassis wiring and 1.5A for power transmission. The combined equivalent of these two would be a 17 gauge wire. Using the same chart, the ampacity for 17 gauge wire is 19A and 2.9A respectively.  In normal operation of a locomotive, or maybe even two, you will likely never exceed the power transmission ratings for either wire, and all will be well. However, in the case of a short, the current that is delivered will largely depend on the resistance of the wire (which is dependent on length) and the ability of the transformer to deliver it.

Whether the wire melts through will dependent on the amount of heat generated by the overcurrent condition, the type of insulation on the wire, and also how the wire is bundled (or not), and what is above and beside it. Running under a train table, could cause it to heat up if it can't dissipate the heat quickly enough. However, once one wire melts through, the load will double on the other causing it to heat further, and if it get's hot enough, it's resistance will rise and may reach an equilibrium at less than your upstream circuit protection (which remember is probably bigger since the calculations were based on a thicker wire size).

How long will this stasis remain? Will you even detect it before it's too late? Will it catch fire? Furthermore, at what length of wire will the resistance cause this to happen? How do I size the breaker/fuse properly?  All valid questions.

All of which can probably be calculated using resources online. But why risk it? Just buy a bigger wire.

Sorry if I sound like a broken record, but there are still far too many structure fires due to electrical wiring mishaps.