How to set up a grounding wire

A pipe.  Typically, your electrical panel is ground to a pipe.

@AlanRail posted:

A pipe.  Typically, your electrical panel is ground to a pipe.

Unfortunately he's probably talking about a layout "common" and not a "ground", earth or otherwise.

Forget the pipe.

Mike

Yes... common.

Potentially, yes - it's commonly referred to as a "bus wire". For track power, you run a wire (typically 14 gauge) from the negative post of your transformer under the layout and basically following the tracks above all the way back towards the transformer or wherever you want the wire to end. The wire does not connect to anything at the far end, but can be capped at the end with a wire nut. The wire, itself, can held in place with wire clips or hangers to the underside of the layout.

You can then tap into the bus wire, as needed, to connect to various power drops around the layout.

It is possible to use the same ground bus wire for accessories, but you may have to consider the type of accessory and its particular electrical requirements.   

I'm curious about this too. My home has nearly all PEX, PVC, etc. for "pipes".  For us electrically challenged- what would be a suitable alternative to a pipe?  I have track running within 3' of the main breaker box in my basement. Can I just run a wire from a common terminal or one of my outside rails, and attach it to a part of that box? Is one wire enough? I'd be interested in hearing what others have done, and whether they saw any improvement in performance. Thanks!

Riche, You hit on exactly what I was wondering... I realized the power had to be specific for different voltage accessories, but I didn't know if the 'common' wire had to be specific too. My track is already wired in blocks, so now I am just doing accessories. It sounds like I would be better to run a 'common' wire along with each voltage of power wire for my accessories. Does that make sense??

John

This is precisely why you should avoid the use of the term "ground" when you really mean "common".

You've been convinced that that your "ground" has to be physically connected to an earth ground, e.g. a water pipe, or a ground screw on the cover of a nearby wall outlet, or your breaker box.  But it's not a "ground", it's a "common".

DO NOT connect your "common" to earth ground unless you have a good reason to do so.   "A good reason" might best come from a licensed electrician.  It shouldn't come from a typical model railroader.

On a practical note:  If you're running TMCC/Legacy locomotives in command mode, and you tie your common to earth ground, you will very likely obliterate your command radio signal and prevent your command control from operating.

Mike

@JDH posted:

Riche, You hit on exactly what I was wondering... I realized the power had to be specific for different voltage accessories, but I didn't know if the 'common' wire had to be specific too. My track is already wired in blocks, so now I am just doing accessories. It sounds like I would be better to run a 'common' wire along with each voltage of power wire for my accessories. Does that make sense??

John

I found it easier to run the two accessory taps on my Z-4000 transformer (one 14 acv, the other 10 acv) to a 12 or 24 tap distribution block (MTH, but there are others) and then a black/red wire pair from each accessory back to the distribution block rather than using a bus wire. I crimp a small spade terminal at each wire end and just screw it onto the paired taps on the block and then to the accessory.

14 acv seems to be a good compromise for most accessories that require from 12-18 acv and anything under that, I use the 10 acv distribution block. 

The two accessory blocks are in the top right of the photo and fed directly from the transformer - the ones on the left are for track power feeds and fed from the TIU. It's a lot messier, now !

Richie... You have answered my question, both in script and image! Looks like the first thing I have to do is look up the voltage for each accessory and plan my blocks. I now understand the difference between the terms 'ground' and 'common', and I can visualize the wiring design. If anyone is looking for me in the next week... I will be under the table!!

Thanks to all, John

I thought grounding to a water pipe was illegal.

The water pipe ground you are referring to is the earth ground for a house wiring system.  That's the same as the grounding prong on a 3 prong 120 V household extension cord or a green or bare wire in your household wiring.

Wiring beginners may find some of this info interesting:

See booklet listed here at this topic's header at ELECTRICAL REFERENCE MATERIALS & MANUALS
See How to Operate Lionel Trains and Accessories (Dad's copy).

On my website start at Toy Train Layout Wiring - Basic .
The above section has links to all kinds of layout/accessory wiring.

Feet

An electrician will run a bond wire from metal piping to a common electrical point in the Main service panel were Home-run ground wires, home run Neutral wires, Ground rods and/ or rebar grounds, and also the service neutral from the utility meter all come together.

This will put all metal in the household likely to be accidentally energized by household current at the same potential, as a common grid. You will also have a low impedance path for any fault current that energizes this grid back to the service neutral. The fault current taking this low impendence path back to the panel will exceed the breaker rating, and thereby tripping the breaker that effectively removes the dangerous fault current.

k

The "common" is part of the OUTPUT of the transformers.   A "ground" wire is part of your house's electrical safety system and (might) be part of the INPUT of your transformers, depending upon a lot of variables, not easily typed here.

They are two distinct wires, and they should never be connected.

Even master electricians and master plumbers get confused with the concept of GROUNDED conductors, GROUNDING conductors and BONDING conductors, none of which have any place in a toy train discussion.

Under my layout, there is a bare #12 wire that runs all along the underside of the table. Any accessory or device that needs to get a return to the main power panel gets soldered at a convenient point on this bus wire.  I use conventional power supplies only and use R/C for the trains.

As Mike stated, the layout "common" and "ground" are terms that are (incorrectly) interchanged.

The house wiring "ground" and electrical code ensures that exposed metal (say a toaster) plugged into the house wiring is at the same electrical potential with water pipes, faucets, etc.  The practice of using grounded outlets and devices keeps you from getting shocks in the kitchen, bath, and other areas of the house.  There's a lot more to the house "ground" and the electrical service into the house that I won't attempt to describe.

For layout power, our transformers are "Isolation" transformers which means the low voltage side is not connected to the incoming 120V house wiring.  Do not attempt to connect the track common (outside rails) to the house ground which will violate this key safety aspect of layout power.

On the low voltage side of the transformer, an older practice of layout builders was to use a "common" bus wire connected to the 'U' terminals of the transformer, and run single hot wires to the track.  This is not a good when electronic controls (especially DCS) are used - best practice is to use a pair of wires (common+hot) for each track feed.

Like A. Bloom, I have a bare #12 running all around the layout, in a loop, into which one wire from every accessory, building, etc. and all outside rails IS tied.  It connects to all U posts.  I would not connect to a water pipe, especially if copper, which is subject to enough corrosion as is.  Also, the house ground should be tied into a copper rod driven into the earth, to avoid inducing corrosion into pipes.  Many  builders save $$ by using rods other than copper, and these have short lives.  Why anyone would want to connect the low voltage circuits of a layout to the house electrical system is beyond me.

Thanks A. Bloom, thanks for the reply!

Forget the 'Ground' word, I have been educated that I should have said 'Common'.

So you are running EVERYTHING to one 'Common'... Tracks and all accessories?

I have 2 questions... do you run separate POWER wires to accessory blocks with similar voltage requirements... for example one for 6-10acv and a separate power wire for 12-18acv?

Also, what do you mean by connecting the 'common' to ALL U posts. I have 3 post war transformers (1KW and 2 ZW) all syncronized. How do I connect the 12 gauge single common to those? I don't and won't be using and electronic controls.

Thanks again, John

For last question, if you connect the U of each transformer to the buss, they are connected.  The ZW's 4 U posts are connected together internally, and you want the Us of all transformers connected externally.  I have one wire from each ZW , Z4000, and others connected to the buss.

I do run a hot wire around the layout, into which I wire the other terminal of accessories.   A 14 gauge hot wire runs from each toggle switch on my control panel to center rail of each of the 70 blocks

@Fast Mail posted:

Feet

An electrician will run a bond wire from metal piping to a common electrical point in the Main service panel were Home-run ground wires, home run Neutral wires, Ground rods and/ or rebar grounds, and also the service neutral from the utility meter all come together.

This will put all metal in the household likely to be accidentally energized by household current at the same potential, as a common grid. You will also have a low impedance path for any fault current that energizes this grid back to the service neutral. The fault current taking this low impendence path back to the panel will exceed the breaker rating, and thereby tripping the breaker that effectively removes the dangerous fault current.

k

Ok that makes sense. This old house isn't wired like that as in 1929 wiring though it has been updated somewhat. Looks like I'll have that changed.

@Mellow Hudson Mike posted:

On a practical note:  If you're running TMCC/Legacy locomotives in command mode, and you tie your common to earth ground, you will very likely obliterate your command radio signal and prevent your command control from operating.

Actually, you will FOR SURE kill any TMCC/Legacy signal!

I have my three Lionel LW train only transformers, two 12vac lighting transformers and one 14vac switch transformer plugged into a power strip.  On the LWs, one connector is labeled "Common" and the other one labeled "U" , which is the variable voltage output.  The transformers are all phased and have a common that are all connected together.  All transformers have two wire only AC plugs.  I can run a wire from any of the variable or constant live wire and use any common on the layout to make a circuit.

The switch of the power strip is in the 110 vac Live, black wire, the wire that is the narrow bladed plug prong.  The wide bladed wire is the Neutral, white wire.  The other plug of the three prong plug is the Ground or Earth and is green.

Charlie

Crying shame the poor original poster used the word ground, which caused a great deal of explanation not related to model railroad wiring or his question making this good question hard to get.

Thanks, Dennis

Yes, I too am SO sorry I used the word 'ground'!!    However, several members translated the post well, and I did get my question answered, and am ready to start work. (I have also learned a lot about 'ground'!)    As you can tell, I am a newbie at layouts, and I always learn so much from this forum.

Thanks to all, John

A side note. Your house is not grounded through the pipes, that connection is to ground the pipes. The electrician should have driven a long copper rod into the ground and that is what grounds your house.

As a side note:  I would recommend avoiding tying anything into house piping if it is copper.  Copper pipe is susceptible to galvanic action and electrolysis, which over time causes pinholes.  Many houses in my area are having these failures.  As a non-railroad item and in an effort to leave you more $$ for trains, I strongly recommend finding out what material your house ground rod is made of.  If not copper, life is less than 10 or so years.  A cable should come out of your house near the main breaker/fuse box and be connected to a rod in the earth.  A good electrician should e able to check this out

ATTENTION

Any who are attempting to “ground” anything to your water pipe.

This is dangerous if you don’t know exactly what you are doing.

The issue is a DIFFERENCE OF POTENTIAL, which is what you are attempting to avoid when “grounding” to your water pipe.
When there is a DIFFERENCE OF POTENTIAL-YOU COULD BECOME THE CONDUCTOR FOR THAT DIFFERENCE, because it will seek to balance its potential.

If I’m any doubt don’t do it

hire a professional

but if you believe you can…

make certain that the actual water pipe coming into your home is metal, then be certain there is a BOND between that feed pipe and your copper pipes, at the water meter.
If you don’t have copper water pipes-then you must find the ground that your homes electrical panel is grounded to-and that is where you shall ground also.

GROUND and COMMON are not the same thing.

Here’s some good reading

https://www.m.electrical101.co...ectrical-ground.html

https://www.thespruce.com/what-is-grounding-1152859

remember people die at home because they did stuff they shouldn’t have been doing

In reference to 'Grounding' and not the common for the rail, this can be the Achilles Heel to your house wiring.  Proper grounding has all outlets traveling back to the main entrance panel where ground and neutral are tied together and that is the only spot they should be tied together.  At one time, the meter can was the only tie point, but that changed.  The problem comes in when you think you need to ground something and you drive a ground rod and tie that back to something in your house, like a TV and its antenna system if you still do through the air TV.  The phone company also will drive a rod to ground their system.  Where the problem comes is a lightning near miss or strike.  Your house main panel ground, and your installed ground rod will have resistance between them based on your soil.  A 60,000 amp lightning surge felt on the two separate grounds gives you a voltage difference across them equal to the resistance times the amps, so, if you had 20ohms difference between those two rods you would have 1.2 million volts looking to equalize itself somewhere.  All ground rods should be bonded together outside, and in both directions around your house, if you hope to mitigate the situation.  Best thing to do is unplug hobby things not being used.

Personally, I think it would be foolish and dangerous to tie the outside rails into the house neutral circuit.  If you do so and are using a 120-volt tool on the layout, there is serious potential for shock if you are holding the tool and trouch the outside rail, if the tool has an internal failure.

This thread has piqued my curiousity, so I went down to my layout (3 transformers {a PW ZW, a Z4000, and a PH180}--, DCS) and, using a test meter, found 87 VAC between a 120VAC receptacle hot and the outside rails and between receptacle hot and the center rail.  That will take some thought to figure out, since supposedly the transformers provide complete isolation.

I am, in no way suggesting that anyone tie their model railroading power source to their home ground

@RJR posted:

Personally, I think it would be foolish and dangerous to tie the outside rails into the house neutral circuit.  If you do so and are using a 120-volt tool on the layout, there is serious potential for shock if you are holding the tool and trouch the outside rail, if the tool has an internal failure.

Well, since tying the outside rails to your house ground would also kill any TMCC/Legacy signal, it's a doubly bad idea.

Drummer, I didn't mean you.  Look at first few posts of this thread

"This thread has piqued my curiosity, so I went down to my layout (3 transformers {a PW ZW, a Z4000, and a PH180}--, DCS) and, using a test meter, found 87 VAC between a 120VAC receptacle hot and the outside rails and between receptacle hot and the center rail.  That will take some thought to figure out, since supposedly the transformers provide complete isolation."

You have discovered a very serious fault. I suggest that you contact an electrician immediately.

In the meantime, disconnect all three transformers and separate their output wires from the layout and from each other (if you have, for instance, common connections.) Leave them plugged in. Try to determine which transformer(s) is/are causing this leakage.

Arthur:  I would like to hear from other forumites what results they show from such a test.  I am not about to hire an electrician to search around on the layout, which is where any fault would be.  I agree that checking the transformers on the layout is the place to start,  one each of ZW, Z4000, PH180.  But there are also some wall warts, such as for WIUs & TIUs.

@RJR posted:

Arthur:  I would like to hear from other forumites what results they show from such a test.  I am not about to hire an electrician to search around on the layout, which is where any fault would be.  I agree that checking the transformers on the layout is the place to start,  one each of ZW, Z4000, PH180.  But there are also some wall warts, such as for WIUs & TIUs.

Exactly what type of meter did you use? And you are measuring from the HOT (narrow prong) in the receptacle?

Problem solved!  The layout has a receptacle bar/power strip into which all transformers and wall warts plug.  The bar is in turn plugged into a wall receptacle.  So by unplugging the latter, my layout is completely disconnected from the power lines and I can safely use an ohmmeter, pushing a prong into hot, neutral, and ground receptacle prongs on the receptacle bar .  Each of the 2 TIUs is powered by a Radio-Shack switchable out voltage wall wart, through the AUX port

Using an ohmmeter between a hot or a neutral prong of a receptacle in the now-unplugged receptacle bar and the outside rail gave about 15 megohms.  I started unplugging transformers, one-by-one, and this didn't change.  I then unplugged the the two Radio Shack wall warts that each feed a TIU and disconnected them from the TIUs.  I found 11 megohms of resistance between the each input receptacle prongs of the wall warts and each of the terminals on the output jack.   These were widely used years ago, and in fact were highly recommended by a DCS guru.  They were switchable voltage out, 18 or 20 something volts.  I am sure many of these are in use and I urge all such users to run tests.

Next step will do go through my collection of old wall warts and find two of appropriate volts output & amps capacity

Attached are pictures of the wall wart in issue. 

"Arthur:  I am not about to hire an electrician to search around on the layout, which is where any fault would be.  I agree that checking the transformers on the layout is the place to start,  one each of ZW, Z4000, PH180.  But there are also some wall warts, such as for WIUs & TIUs."

In the "you can't win" category, I often suggest that posters try to do their own trouble-shooting, and get told "I am a complete (fill in the blank) when it comes to electricity."

On the other hand, when I read about a very potentially dangerous electrical situation, I suggest an electrician, only to be told that the poster will DIH.  OK, fine with me.

And...once again...we did not hear the whole story from the original post. The wall warts add an interesting slant to the narrative.  My fault, I admit, for not waiting until all the evidence is in, and the thread has matured.

How is a leakage of 120 Volts through 11,000,000 ohms creating a voltage reading of 87 Vac from line hot to a (supposed) isolated track system load?  I await the explanation with bated breath.

Arthur, I was not the OP.

In answer to your final question. it is possible if the only load is a test meter.  The test meter was the only load between the outer rails and the 120-volt hot.

What is clear is that as soon as the wall warts were unplugged from the 120-volt circuit, the 87VAC dropped to zero.  Since the wall warts' outputs only were connected to the AUX ports on 2 TIUs, the answer would also depend on the internal circuitry of a TIU AUX port.

When I have unsnaked the wall warts' leads from my control panel, I can measure their characteristicss more easily.

Regarding the general subject of wall warts, I understand that they are a frequent cause of fires (which may not spread beyond the wart.

@RJR posted:

Regarding the general subject of wall warts, I understand that they are a frequent cause of fires (which may not spread beyond the wart.

@RJR

This is a seriously important statement, from a safety perspective, with potentially huge implications for us hobbyists since most of us use several of them.

Those that are UL listed, or other international equivalent, should never have this kind of problem.

How broadly does it occur?  Do you have a technical reference that supports this claim?  Or is it simply internet hearsay and/or urban legend?  (I'm not trying to badger you.  I'm just trying to find the facts before such a fire shows up on my layout.)

Mike