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Over on The Lionel Train Group there is a discussion going on about buying refurbished ZWs . The ones in question come from Tinman3rail.

I post this because now I'm concerned that I may have a dangerous piece of equipment that I have to dispose of.

So I actually have one of his rebuilt ZWs. I've had it for 3 years with no issues.

It has the 3 pronged plug. My setup is that I use TSV diodes for my Lion chief stuff and 3 amp breakers on the 4 outputs. Then it is plugged into a power strip. Do I need to have it rewired it for a 2 wire plug? Get rid of it? Check the configuration of the rebuild?

I ask because there are a number of guys over here that know alot more than I do about it and if you didnt and I trust this group more than Facebook.

Thanks in advance.

Last edited by Oldegreybeard
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@ADCX Rob posted:

Cut the grounding post off of the plug leaving just the two spade connectors and that will negate the poor choice of this company to attach that post to the transformer chassis. It defies all logic as to why they think that is an improvement or upgrade... they are not engineers or electricians by training or education over there.

Agreed, and with extreme emphasis.

Mike

Hold on, While I would never rebuild a ZW with a three prong grounding plug, and would use a polarized plug instead.   Where is the ground going?  To the frame of the transformer?   I don't see it hurting anything.  Primary is isolated from the secondary and hopefully isolated from the frame, which it shouldn't since you didn't blow the breaker plugging it in.  Leave as is.   If it ain't broke, don't fix it.

Last edited by superwarp1
@superwarp1 posted:

Hold on, While I would never rebuild a ZW with a three prong grounding plug, and would use a polarized plug instead.   Where is the ground going?  To the frame of the transformer?   I don't see it hurting anything.  Primary is isolated from the secondary and hopefully isolated from the frame, which it shouldn't since you didn't blow the breaker plugging it in.  Leave as is.   If it ain't broke, don't fix it.

It is broke.  Someone broke it, although with the best of intentions.

Mike

@ADCX Rob posted:

Well, you've just described the problem... if a track tie(or other layout component/wire) comes into contact with the base of these mal-modified ZWs, the layout, & secondary, becomes grounded.

I'm getting rid of the prong if it isnt safe. For curiosity I'm going to check and see if it is grounded to the frame or where.

You'd think there would be liability issues modifying and selling things like that.

@ADCX Rob posted:

Well, you've just described the problem... if a track tie(or other layout component/wire) comes into contact with the base of these mal-modified ZWs, the layout, & secondary, becomes grounded.

And the worse that will happen is he loses TMCC signal, highly unlikely.  Cut if you want but that's hackster all the way.  Better to remove the cord and replace with a polarized plug.

Somewhere up above in this thread someone used the word "hopefully." That's never a good sign where DIY and lots of electrons are involved.

Cut off the ground lug. AND open the transformer, find the ground wire and cut it off at the choke of the cord. (The choke is the industry term that refers to the place where the cord or cable sheath ends, and the individual wires keep going.)

OR get a non-polarized cord and re-install it yourself. Cords like that are readily available at suppliers, or at the end of small appliances. The reason that we suggest non-polarized is so that phasing can be accomplished easily.

ZW's didn't have polarized plugs because the NEC doesn't require them on appliances that are not switched, and/or are double-insulated.  No switch -- no danger of the customer touching an energized portion of the appliance.  ZW's don't have on-off switches.

We have admonished, gently, those who use three-wire cords here recently. That advice hasn't changed.

Last edited by Arthur P. Bloom

Kazar

First, I replaced all of my ZWs with more modern MTH or LIONEL power sources. This is even after I had both repaired.

WHY, because they are fire hazards. There are no fuses within. Shorts rely on slow-acting copper discs to flex to shut off power. In a large layout waiting for those discs to flex could take minutes not seconds. All the while, the short is burning thru your layout.

As an engineer, I used to do home inspections after fires for insurance companies. Electrical fires were usually the fault of non-UL approved appliances. The early ZWs were considered toys and not really on UL's radar.

And I know about all the stories that start with "I have used my ZW(s) for 50 years and no issues."

That is like the guy failing from a tall building.

Thru an open window you tell at him, "How's it going?"

He yells back, "So far so goooood!"

Last edited by AlanRail
@AlanRail posted:

Kazar

First, I replaced all of my ZWs with more modern MTH or LIONEL power sources. This is even after I had both repaired.

WHY, because they are fire hazards. There are no fuses within. Shorts rely on slow-acting copper discs to flex to shut off power. In a large layout waiting for those discs to flex could take minutes not seconds. All the while, the short is burning thru your layout.

Copper disks?  The circuit breakers are pretty traditional thermal breakers, but they don't have copper disks.


I don't see an overt example of user/operator error in Alan's description.  What am I missing

I suspect the inference that a short was left smoldering for minutes is what Rob is referring to.  Leaving the trains running unattended is certainly operator error.

Well, that, and if the wiring isn't sized properly, the breaker will never trip, just like with modern power supplies.  Having undersized common returns with large layouts drawing 40-50 amps is a recent issue, those power supplies will never trip while the common burns away.

Last edited by ADCX Rob

The idea that ZW's are inherently fire risks is basically a fallacy,sorry. Yes, the breaker in there is not designed to trip fast, it is a thermal breaker and they are relatively slow. That said, I doubt unless someone has done really stupid wiring , like way undersize wire feeding something like an engine and there is a short, it is unlikely to cause a fire. As long as the ZW has been maintained, has the proper cord on it, has had the inside checked out for possible shorts and the like, there isn't really anything that earth shattering about it, it is pretty generic technology.

Is a modern transformer better? A modern transformer could catch fire, too, if someone wires wrong or they overload it, there are ways  circuit breakers will fail on them, too,or they can overheat and cause a fire from a problem inside the transformer, it happens. As others have pointed out, put a fast blow breaker on the output of the transformer and you eliminate much of the risk.  I realize safety standards have changed since the 1940's, but the reality is that it isn't like a ZW is like a ticking time bomb either, it might have a slightly higher risk of having problems than a modern one (Plus I seem to recall they made ZW's in the 50's and 60's, when I am sure standards had changed).

Look, you leave anything going and there is a risk. My son left the fan on in the bathroom in his apartment that has a heating unit in it, and it caused a fire, and that was put in only a couple of years ago. It isn't that hard to have the transformer on a power strip to shut it down if you don't want to unplug it *shrug*. I agree with GRJ, there are things we leave on (like chargers for phones, battery powered tools) but we also power down things we aren't using routinely.

I am not saying everyone should run out and buy a ZW or KW or whatnot, all things considered a modern transformer might be easier, like having a fast blow thermostat and made to modern UL standards by default, but it also doesn't mean a ZW is like some dangerous appliance CPSC caused to be recalled. On the other hand given the cost of modern transformers, someone might find an older transformer in their price range *shrug*.

@ADCX Rob posted:

Well, that, and if the wiring isn't sized properly, the breaker will never trip, just like with modern power supplies.  Having undersized common returns with large layouts drawing 40-50 amps is a recent issue, those power supplies will never trip while the common burns away.

Agreed.  I see now where you're coming from.  But a problem with a product, and a problem with a product used incorrectly are two very different things.

UL would rate the product, and has always rated products "in their intended usage".

Because of it's age, and the age of the standard to which it was manufactured, the ZW is inherently less safe than newer transformers or powerhouses.  Does this make it more dangerous?  Yes.

Does it make it just simply "dangerous"? Not so easy to say, but newer ones have had the benefit of much more scrutiny and experience behind their design, and so, if UL listed, must by definition be safer.

Using either, old or new, incorrectly can lead to a fire regardless of the fact that the newer ones are safer.  This fact makes misuse a red herring when it comes to evaluating whether a ZW, as a product, is dangerous.

Mike

Last edited by Mellow Hudson Mike
@bigkid posted:

The idea that ZW's are inherently fire risks is basically a fallacy,sorry.

@bigkid,

You've hit on something very important here.  What does history say?  It says "Safe" because there has been no recall ever issued by the CPSC at any time, as far as we can tell.

Safety folks call this "Proven in Use" and rely on it very frequently in making judgements about the relative safety of products and the components that make them up.

How it works is that data from the real world says that there has been no significant outbreak of fires or burns from overheating components making up ZW's since they were introduced.

As a result they have been proven in use, and are safe, as long as:

1.) They continue to be used as intended.

2.) They are not modified from the existing design, which is the basis for the claim of proven in use (i.e., the unmodified design was used to manufacture the ZW's making up the statistical population of product from which the data came).

No. 2 immediately above is the issue that launched this thread.  So, did the recent in-the-field modification that added a ground pin to the wall plug affect safety?  Yes.

Conclusion: Restore the ZW to it's original state and it will return to being safe, if used as intended.

Mike

Most Lionel transformer have a Bakelite plastic cases and plastic buttons and levers for control isolating the metal inside from the user.  This is just like modern electrical tools likes drills and saws that have plastic cases and two wire plugs.  The tools have polarized plugs to insure the tool switch is wired to the hot smaller plug.

Talking about 1940-50s electronics, here is how my Hallicrafters SA 77 short wave radio was wired.  It did not have a polarized plug.  Plugged in one way, the metal case was a hot 110 v to ground with the switch OFF.  Plugged in the other way the metal case was a hot 100v to ground with the switch ON.  It did have plastic knobs.  I replaced the power cord with a ALCI polarize plug with reset and test buttons from a used hair blower.  I made sure the hot wire (small blade one) went to the  on/off switch.  It also had 9 tubes with the tubes wired in series.  It should be easy to find a burned out heater on the tube where the voltage stops.

Last edited by Choo Choo Charlie
@ADCX Rob posted:

Cut the grounding post off of the plug leaving just the two spade connectors and that will negate the poor choice of this company to attach that post to the transformer chassis. It defies all logic as to why they think that is an improvement or upgrade... they are not engineers or electricians by training or education over there.

Yup the old adage “ just because you can , does not mean you should”

As far as a ZW being dangerous, anything can be dangerous if you operate it wrong enough.

This is the breaker on a 180W brick. I found this after a 21” passenger car derailed and when I went to fix it I found the centering spring glowing red as it was shorting to the center rail. (I had always wondered why on occasion we’d always pop a breaker on a TPC with only 1 brick). 1170F36B-DCAB-4FA0-8D8C-A864D31FBB2E

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  • 1170F36B-DCAB-4FA0-8D8C-A864D31FBB2E

Is there any data on unmodified,  postwar ZW's causing fires when used as intended?  I have four and some others and have had no problems in 70 yrs, knock on wood.

I do worry about llithium batteries, their chargers, and electric blankets. 

I actually had my electric blanket catch on fire once with me in the bed.  Luckily, the crackling of the flames woke me up.

I guess there are risks with several things in life.  Especially if you modify them.

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