# New train protection from old transformers



## WildcatRR (Jul 28, 2013)

I have searched the forum threads but can't find where it's located on circuit protection for new trains running with old lionel transformers. Any info would be helpful as I don't want to fry the circuit boards on the newer engines that I have.


Harry


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## cole226 (Feb 8, 2013)

tvs diodes and fast trip 3 or 5 amp inline circuit breakers or fuses.

self resetting breakers work best imho.

link http://www.modeltrainforum.com/showthread.php?t=117026&highlight=circuit+breakers


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## WildcatRR (Jul 28, 2013)

Thanks for the info. best to play it safe than sorry.

Harry


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## DennyM (Jan 3, 2016)

I used this 5 amp circuit breaker with my post-war ZW. It reacts instantly and resets with a push of a button. I put it in-line between the transformer and the track. I just soldered the wires to the plugs.


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## WildcatRR (Jul 28, 2013)

Thanks Denny. Please keep the ideas and types coming.

Harry


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## Krieglok (Sep 7, 2013)

DennyM said:


> I used this 5 amp circuit breaker with my post-war ZW. It reacts instantly and resets with a push of a button. I put it in-line between the transformer and the track. I just soldered the wires to the plugs.
> 
> View attachment 402314


That is a great set up, Denny. Where did you find that circuit breaker?

Tom


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## beachhead2 (Oct 31, 2017)

WildcatRR said:


> Thanks Denny. Please keep the ideas and types coming.


I posted recently about making a box for this same purpose. I took close up pics of the parts so you can see the pics and diode part #'s. Breakers are 3A.

http://www.modeltrainforum.com/showthread.php?t=156042&highlight=breaker+box


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## highvoltage (Apr 6, 2014)

Krieglok said:


> That is a great set up, Denny. Where did you find that circuit breaker?
> 
> Tom


A quick search based on part number came up with this site:

https://marvac.com/products/5-amp-pushbutton-circuit-breaker-zing-ear-ze-700-5-5a


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## DennyM (Jan 3, 2016)

Krieglok said:


> That is a great set up, Denny. Where did you find that circuit breaker?
> 
> Tom


There are some on Google just type in 5 amp AC circuit breaker. I bought mine at Benton Electronics in Benton Harbor, MI which is about a 20 mile drive for me.


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## Norton (Nov 5, 2015)

Thermal Breakers are very low to react. Modern Transformers trip in under 10 milliseconds. Thermal breakers are 10 to 100 times that. If you run conventional along with command this is the best out there now. Use these along with TVS's

http://www.traintekllc.com/dcc-specialties-psx-ac-3-rail-circuit-breaker/

Pete


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## DennyM (Jan 3, 2016)

The 5 amp breakers I used reacted as fast as what comes in modern transformers. I had a couple on the club layout when we had the PW-ZW and they worked perfectly. We have a ZW-L now so they're not needed.


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## gunrunnerjohn (Nov 10, 2010)

Denny, I'd have to disagree that those thermal breakers are as fast as the Lionel PH180 brick breaker. I've used tons of thermal breakers, and as Pete says, they're not lightning fast.

I looked, but I find no specs for the *Zing Ear ZE-700-5 5A*, so I'm assuming from the descriptions and the price they're plain garden variety thermal breakers.


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## bluecomet400 (Sep 13, 2015)

What about the breakers sold by Dallee?

https://www.dallee.com/5-Amp-Circuit-Breaker-with-Spike-Protection-1112 


I'm also very interested in finding the right way to protect the electronics in my modern trains. I run mostly prewar and have 5 perfectly good ZWs, so it's hard to justify the expense of a modern transformer to run a handful of modern locos.

John


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## Norton (Nov 5, 2015)

In electronics fast is relative. Here is a graph of a typical thermal breaker. Some are faster but none come close to an electronic breaker. 









Maybe to put in perspective. The breaker in your post war ZW is like a 50cc moped. Modern Thermal breakers might be like a 250 cc motorcycle. Fast compared to the moped. Electronic Breakers are like a Formula 1 car.

Pete


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## DennyM (Jan 3, 2016)

gunrunnerjohn said:


> Denny, I'd have to disagree that those thermal breakers are as fast as the Lionel PH180 brick breaker. I've used tons of thermal breakers, and as Pete says, they're not lightning fast.
> 
> I looked, but I find no specs for the *Zing Ear ZE-700-5 5A*, so I'm assuming from the descriptions and the price they're plain garden variety thermal breakers.


I understand John. I'm just relating my experience with those circuit breakers. I tested them several times by jumping the third rail to the ground rail with a screwdriver before I let anyone run trains.


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## Lehigh74 (Sep 25, 2015)

I originally used 10-amp blade type mini fuses. I switched to magnetic-hydraulic breakers, but I got ones that are too slow. The 10-amp fuses almost always beat the breakers, so I still rely on the fuses. 

I have three (or more) questions.

How fast is fast enough? At 4 times rating, a thermal breaker will trip in .6 to 5 seconds, a magnetic-hydraulic (slow) breaker will trip in .1 to 4 seconds, a magnetic-hydraulic (fast) breaker will trip in .03 to .5 seconds and a blade fuse will blow in .08 seconds. How fast is the PSX-AC?

How much current is too much? How much current will it take to damage electronics in modern trains? Is 20 amps too much? 40?

What am I willing to pay? I like the setup that beachhead2 made, but I think those Eaton breakers go for around $50 each. I also like the PSX-AC, but they are also $50 each. I could get some faster magnetic-hydraulic breakers for around $25 each. I can get mini fuses for $.19 each if I buy 100 of them. Maybe its dumb to ask this question, since one fried circuit board costs more than 4 of the PSX-AC breakers, but I still ask.

http://www.littelfuse.com/~/media/a...cle/blade-fuses/littelfuse_mini_datasheet.pdf


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## beachhead2 (Oct 31, 2017)

Lehigh74 said:


> I like the setup that beachhead2 made, but I think those Eaton breakers go for around $50 each.


No, I bought them from AutomationDirect for $9.25 each (+free S&H but that was before Christmas).

https://www.automationdirect.com/adc/Shopping/Catalog/Circuit_Protection_-z-_Fuses_-z-_Disconnects/UL_1077_Rated_Supplementary_Protectors/Single_Pole_Supplementary_Protectors_(0.5A-63A,_FAZ_Series)/C_Curve_(0.5A-63A,_FAZ-CXX-1-SP)/FAZ-C3-1-SP


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## Lehigh74 (Sep 25, 2015)

OK. That makes the Eaton breakers more attractive, but now that I have looked at their data sheet, I’m not sure. At 900% of their rating, they will trip in .003 to 3 seconds.

But I’m still wondering what guidelines need to be considered when selecting circuit protection. Theoretically, a short circuit will result in infinite amps, so maybe I should be looking at the high end of the time-current charts. If so, (at 10 times their rating) the Eaton thermal-magnetics will trip in .003 to .015 seconds, a slow magnetic-hydraulic in .010 to .3 seconds, a fast magnetic-hydraulic in .010 to .09, a thermal in .12 to .7 seconds and a mini fuse in .01 seconds.


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## Matt_GNo27 (Feb 7, 2016)

bluecomet400 said:


> What about the breakers sold by Dallee?
> 
> https://www.dallee.com/5-Amp-Circuit-Breaker-with-Spike-Protection-1112
> 
> John


The Dallee Circuit Breaker with Spike Protection uses a thermal breaker and a TVS diode, and frankly, at $25 are a ripoff. 

You can get 5 amp thermal breakers from Digi-Key for $2.47 here. Digi-Key has TVS diodes for $0.65 a piece here.

To the electronic wizards here, perhaps you can explain something to me:

It is my understanding that circuit breakers/fuses protect the transformer from high current and TVS diodes protect the sensitive electronics in the engine. If that is the case, shouldn't an appropriately rated thermal breaker used in conjunction with TVS diode be sufficient protection when using postwar transformers with modern locomotives?


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## DennyM (Jan 3, 2016)

Yes Matt, I seem to remember gunrunnerjohn posting something about TVS diode in-line with a 5 amp breaker awhile back.


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## beachhead2 (Oct 31, 2017)

Matt_GNo27 said:


> It is my understanding that circuit breakers/fuses protect the transformer from high current and TVS diodes protect the sensitive electronics in the engine. If that is the case, shouldn't an appropriately rated thermal breaker used in conjunction with TVS diode be sufficient protection when using postwar transformers with modern locomotives?


I am not an electronics wizard so someone else will need to confirm but that is my understanding, yes. Breakers are for the transformer. Diodes are for your modern electronics. I have TVS diodes at the ZW posts and inside my breaker box. I've seen posts where GRJ recommends the best possible place for a TVS diode is INSIDE the engine. But I have not done this yet.


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## highvoltage (Apr 6, 2014)

Breakers and fuses also protect sensitive electronics inside modern engines from excess current.

Transformers have breakers for their own protection, but might not trip fast enough to protect engines.

TVS diodes protect electronics from voltage spikes.


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## DennyM (Jan 3, 2016)

Inside the engine? Would you solder them to the roller contacts?


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## beachhead2 (Oct 31, 2017)

DennyM said:


> Inside the engine? Would you solder them to the roller contacts?


That's right. Inside. I have no idea how. GRJ will have to weigh in.


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## Matt_GNo27 (Feb 7, 2016)

highvoltage said:


> Breakers and fuses also protect sensitive electronics inside modern engines from excess current.


In what scenario(s) would you have a high current in electronics? In the case of a short circuit from say, a derailment, the current wouldn't be going through the engine.


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## KenH54 (Jan 24, 2018)

file:///Users/Ken/Pictures/download%20(11).png
Pic of TVS Diode


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## DennyM (Jan 3, 2016)

Matt_GNo27 said:


> In what scenario(s) would you have a high current in electronics? In the case of a short circuit from say, a derailment, the current wouldn't be going through the engine.


It would be for Legacy, TMCC or LC+ engines Matt. They run on 18v.


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## Matt_GNo27 (Feb 7, 2016)

DennyM said:


> It would be for Legacy, TMCC or LC+ engines Matt. They run on 18v.



Thanks, Denny, but I don't mean what scenario in terms of what trains you're running, but what kind of electrical fault does the fast-acting breaker protect against that might do harm to the engine? In the case of a track-short, e.g. from a derailment, you would not have high current going through the engine's electronics, correct?


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## DennyM (Jan 3, 2016)

Matt_GNo27 said:


> Thanks, Denny, but I don't mean what scenario in terms of what trains you're running, but what kind of electrical fault does the fast-acting breaker protect against that might do harm to the engine? In the case of a track-short, e.g. from a derailment, you would not have high current going through the engine's electronics, correct?


What I was saying is that command controlled locos run on steady18v and that is what the circuit breakers are protecting the electronics from. When there is a derailment or short and the power is not killed right away, the circuit boards can get be damaged. On older transformers the circuit breakers only protect the transformer. Sorry, I'm not good at explaining things.


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## bluecomet400 (Sep 13, 2015)

Doesn't the Dallee product provide both overload and voltage spike protection in one unit? Why wouldn't this be a good way to go?


John


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## DennyM (Jan 3, 2016)

I just looked it up John that would work. $24.95 is a good price to protect you locos.

https://www.dallee.com/5-Amp-Circuit-Breaker-with-Spike-Protection-1112

https://www.dallee.com/3-Amp-Circuit-Breaker-with-Spike-Protection-1111


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## balidas (Jun 3, 2011)

Matt_GNo27 said:


> In what scenario(s) would you have a high current in electronics? In the case of a short circuit from say, a derailment, the current wouldn't be going through the engine.


The main point in installing TVS in your locos is to protect them should you decide to run them on someone elses layout who may not have protected their layout with fuses & TVS.


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## Lehigh74 (Sep 25, 2015)

bluecomet400 said:


> Doesn't the Dallee product provide both overload and voltage spike protection in one unit? Why wouldn't this be a good way to go?
> 
> 
> John


The problem with the Dallee (if it is a thermal breaker as Matt said) is that it is slower than a magnetic hydraulic or a thermal magnetic, but you are paying the same price as a magnetic-hydraulic. You do get a TVS diode with it, but they are cheap and easy to install.


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## Matt_GNo27 (Feb 7, 2016)

DennyM said:


> I just looked it up John that would work. $24.95 is a good price to protect you locos.
> 
> https://www.dallee.com/5-Amp-Circuit-Breaker-with-Spike-Protection-1112
> 
> https://www.dallee.com/3-Amp-Circuit-Breaker-with-Spike-Protection-1111


No, it's not a good price. See my earlier post in the thread. You can get a thermal breaker, which is what the Dallee circuit breakers are, and a TVS diode for $3.12 plus shipping at Digi-Key. So with the Dalleee item, you're paying $21.83 too much.


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## Matt_GNo27 (Feb 7, 2016)

balidas said:


> The main point in installing TVS in your locos is to protect them should you decide to run them on someone elses layout who may not have protected their layout with fuses & TVS.


No, that's not the main point. I am trying to understand what the cost-benefit of a fast-acting breaker is. The consensus seems to be that TVS diodes protect your engines from voltage spikes and circuit breakers protect your transformer from high current. Then there is a group of people that say that you should have fast-acting breakers to protect modern engine electronic components. 

My question—which no-one has answered—is why and in what circumstances would this protection be necessary? Again, my understanding is that in the case of a short circuit caused by a derailment, there is NO current going through the engine's components. Am I wrong?

What are *specific* scenarios in which you would have a high enough current going through the engine's electrical components to do damage?


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## bluecomet400 (Sep 13, 2015)

I'm thoroughly confused. Here's a response directly from Dallee Electronics when I asked what type of breakers they are selling:




It looks like there are several types of breakers (thermal, thermal magnetic, etc.) What type of breakers are you selling?

"These are thermal which is why they are called "mechanical circuit breaker" - as shown below in the trip graphs. Magnetic breakers can trip very fast and are not really needed for model train use. They also cost a fortune compared to standard thermal breakers (which were incorporated in most power transformers dating way back)."


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## Lehigh74 (Sep 25, 2015)

bluecomet400 said:


> I'm thoroughly confused.


You’re not alone there John. This thread has prompted me to reexamine the circuit protection I am using and as noted above, I still have some questions. I would be interested in seeing the trip graphs for the Dallee breaker. Do they look like the one in post #14? If so, they are overpriced. The Sensata magnetic-hydraulic ones that I got are around the same price ($25). I got 10 amp breakers and my 10 amp fuses always beat them. Maybe if I got the 5 amp magnetic-hydraulics, they would be faster than the fuses.


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## Matt_GNo27 (Feb 7, 2016)

bluecomet400 said:


> I'm thoroughly confused. Here's a response directly from Dallee Electronics when I asked what type of breakers they are selling:
> 
> 
> 
> ...


Dallee's response is in line with the common statement that you use TVS diodes to protect the engine's electronic components and circuit breakers to protect the transformer.


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## rkenney (Aug 10, 2013)

Just to confuse slightly more, here are some alternative protective devices that have not yet been discussed, PTC and eFuses.

View attachment AND9513-D.PDF


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## bluecomet400 (Sep 13, 2015)

Yesterday I went to my local electronics store and asked what they had for circuit breakers. They had the exact breakers Denny posted earlier in this thread, so I bought a 5-amp and a 10-amp. I did a little experiment with them, along with my ZW and a modern MTH Z750. Here are the trip times:

ZW internal breaker: 3.79 seconds
ZW with external 10A breaker: 2.95 seconds
ZW with external 5A breaker: 1.12 seconds
MTH Z4000 internal breaker: .43 seconds

How fast is needed for adequate protection?


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## gunrunnerjohn (Nov 10, 2010)

John, the faster the better.

How did you provide a load to test the trip times?


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## tootle (Dec 11, 2013)

I'd like to get back to a question that Matt_GNo27 asked back on page 4 that doesn't seem to have been addressed.

There's been a lot of ink spread regarding the size, speed and type of these "secondary" breakers, but I'm still trying to understand why they're needed. Under what conditions? What TYPE of short are they protecting against?

I agree with the use of TVSs to suppress surges that can harm electronics, but I'm coming up short on what the secondary breakers are protecting and why.

Examples, please.


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## Pebo (Sep 27, 2015)

bluecomet400 said:


> Yesterday I went to my local electronics store and asked what they had for circuit breakers. They had the exact breakers Denny posted earlier in this thread, so I bought a 5-amp and a 10-amp. I did a little experiment with them, along with my ZW and a modern MTH Z750. Here are the trip times:
> 
> ZW internal breaker: 3.79 seconds
> ZW with external 10A breaker: 2.95 seconds
> ...


I would want something like the Z4000.
Back when DCS came out (spring 2003?), I got it right away and (this is before the better made VL TIUs) fried 2 TIUs before the ZW breaker tripped.

I then added in line 10 amp fuses (which were a pain).

Peter


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## bluecomet400 (Sep 13, 2015)

gunrunnerjohn said:


> John, the faster the better.
> 
> How did you provide a load to test the trip times?



I turned the track power up to 12 volts, then connected a wire between the center and outer rail. From that, I documented the trip time of the ZW internal breaker. Then, I spliced-in the 5-amp breaker and then the 10-amp breaker. 

I did the same thing with the MTH transformer, and its breaker tripped the fastest. 

From what I can tell, if I'm going to continue using the ZW, I need to do 2 things:
1: Add external circuit breaker, but which kind?
2: Add TVS, but how many, and where?
Is this correct?

John


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## Taylor622 (Jan 31, 2013)

Has anyone wired up a ZW to a Lionel Powerhouse Lockon 6-22914 for tubular track? The lockon is designed to be powered by a Lionel Power House but why wouldn't a ZW work too? There is the issue of adapting the two wires from the ZW to the 3 connector plug in the Powerhouse Lockon. I believe the outside connectors are used for power input.


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## DennyM (Jan 3, 2016)

Taylor, that is for a Lionel Powerhouse. You need a regular lockon or solder the wires directly to the track. Keep in mind the U terminals should be connected to the outside rail and the A, B, C or D terminals the center rail.


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## Lee Willis (Jan 1, 2014)

Matt_GNo27 said:


> . . .
> 
> My question—which no-one has answered—is why and in what circumstances would this protection be necessary? Again, my understanding is that in the case of a short circuit caused by a derailment, there is NO current going through the engine's components. Am I wrong?
> 
> What are *specific* scenarios in which you would have a high enough current going through the engine's electrical components to do damage?


My thoughts, too. I have only modern power supplies (ZW-L and CW-80s) with their own protection, and that is enough to protect them, and cut short circuits before they can hurt the wires, feeders, etc. on my track. I don't see how a short circuit can affect the electronics inside a loco - for that it would have to be a long circuit, to coin a phrase. 

I've had lots of short circuits over the years due to many causes, always cleared by the breakers, which do operate rather slowly maybe, but fast enough. Never had any damage to locos.

Voltage spikes are another matter, but I don't protect for those. Just take my chances. So far (fifteen years), so good.


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## gunrunnerjohn (Nov 10, 2010)

The TMCC Direct Lockon is designed specifically for constant voltage command operation. Also, it stomps on the DCS signal, so it's not compatible with MTH PS2/3 locomotives.


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## bluecomet400 (Sep 13, 2015)

After much searching for fast-acting breakers that don't "break" the bank account, I settled on in-line fuse holders with 10-amp fast-blow fuses. I spliced them into the hot leads going to each track. 
Some operators say TVS diodes are needed, some say they are not. Do they do any harm if I add them? If they don't, I'd rather err on the side of caution. 

I just ordered my first MTH DCS setup (TIU and remote). The next step will be modern transformers; until then, I'm using my ZW with the external fuses.


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## Scotie (Sep 27, 2013)

I think most will agree that to protect the boards in the engines the TVS are a must! Inexpensive protection.


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## tootle (Dec 11, 2013)

Operating with newer equipment solves a lot of fault clearing problems, but with older transformation, e.g., ZW's, garden variety shorts out on the tracks may not always be cleared by the transformer breaker. I've had a couple of instances where I've cooked/melted some equipment and the transformer breaker gave no indication of a problem.

In one instance I had a 249 locomotive hang up on an 1122 switch. Totally unapparent until I noticed the smell and smoke from melting plastic. Another time a Cop and Hobo car decided to self-destruct in a similar manner after it developed an internal short (manufacturing defect) while sitting on a siding.

Both of these instances occurred at the outer reaches of the layout (read "high impedance"), so I suspect that the fault current remained relatively low and under the radar of the transformer's internal breaker.

So, even though there doesn't appear to be an urgent reason to install breakers/fuses to protect electronics, it's probably not a bad idea to install them just to cover unforeseen damage and general safety.


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## Taylor622 (Jan 31, 2013)

Experimented with the Lionel 6-22914 Powerhouse Lockon. Wired it up to my ZW. No smoke or fire. The LEDs light up green and the trains run. I'm running conventional. I shorted the rails and the current stops and the LEDs light up red. After a few seconds the power to the track comes back on. Seems to be working. Here are the pics of how to connect the ZW. I made a Molex connector to fit.


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## DennyM (Jan 3, 2016)

Good for you. I'm glad it worked out.


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## indigo (Jan 8, 2020)

*Can I learn PLC programming just by myself?*

Take my congratulations.


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