I have seen a few places where people are recommending you “ground” your Central Station or Booster. Where exactly are people grounding too? Does installing a GFI outlet help this issue and/or eliminate the need for grounding? Any thoughts on basic electronic safety and DCC would be appreicated. Christian
Don’t.
If you have multiple components, they do need to be tied together with a common line so they all have the same reference, and in the case of Loconet, excessive currents that may flow between two boosters in separate power districts when a locomotive bridges the gap.
But do not connect those items to an earth ground. The low voltage side of the power supply is isolated from the high voltage and doing that defeats the purpose.
“Ground” and “Common”. Many confuse those terms.
Another example is in a DCC decoder. Common is the plus voltage.
Rich
Actually, Digitrax does recommend connecting to an earth ground at one point in the system, usually the command station/booster. They also note the difference between a common and a ground. See the last paragraph here:
http://www.digitrax.com/tsd/KB352/powering-your-digitrax-command-control-railroad/
While that was recommended at one time - the current thinking/recommendation is to NOT gound the system other than at the Transformer/Power Supply.
Only a common wire between the Command Station and Boosters as well as any other components that show a Ground (which in these cases is a COMMON).
BOB H - Clarion, PA
LION recommends a HARD GROUND.
LION has several different power supplies. A floating common has its problems since stray voltages will make their home there and make trouble shooting almost impossible.
Thus the common is a HARD GROUND, all stray voltages will go away.
OK, LION has not DCC, obviously the DCC is not participating in a common return, but the system should be plugged into the wall with a three prong plug and trust the manufacturer to do whatever it is he needs to do inside of the box.
LION has a 10.2 volt regulated power supply putting out 12 amps to the tracks.
The LION attached the negative post to GROUND, and the Positive to the railroad. On the Railroad, the LEFT rail is grounded and power is applied to the right rail. Obviously for YOUR application you will need to do things differently, but since subway trains do NOT run backwards, it is not necessary to worry about reverse operations. LION has plans for that eventuality.
The Tortoise power system consists of two DC supplies, the + of 1 is connected to the - of 2, and this is GROUNDED. This leaves the LION with +12; -12 and 24v dc outputs. Tortoise machines are connected to GROUND and to the “Stinger” that is the circuit that drives the turnout, - = normal; + = reverse.
The SIGNAL / Track Detection system has a 16v dc transformer, neg=ground, pos to the system.
The AUX system is 12v dc, neg=ground; pos lighing circuits.
With all of this you can see why the common must be GROUNDED.
OK, YOUR railroad is not this complicated, but good practice suggests that your common must be Grounded.
ROAR
Just to add my 2 cents to what Bob has said, the “ground” in this case is the “safety ground” that keeps line voltage off the chassis. This is the 3rd prong on your electrical cord. Since the power supply is the only place in the system where 120 volts is present, it is the only place where this ground is useful.
Not so. Anytime you establish a comon return you run the risk of having stray voltage on it. This can cause unpredicatble behavior and make the whole thing next to impossible to troubleshoot. GROUNDING the comon return wipes these voltages off of the bus, and will clear many gremlins from your system. If something “funny” is going on, the first thing I check is to be sure that my ground bus is in fact correctly grounded to earth.
Here is MASTER GROUND for Route of LION .
ROAR
The original question was about DCC, where you yourself said there is no common return. Did you read your own post?
For static electricity protection CVP Products/Easy DCC manual recommends grounding command station circuit board and throttle bus to a good earth ground, e.g. metal cold water pipe.
regards, Peter
I am an electrical contractor.
In the above example, I would have grounded to the conduit, not the water pipe. This assuming the electrical system was installed properly. And it does look nicely done in the photo.
Ed
That connection was made by the electricians when they installed all new service, and connected to all of our buildings from this point, instead of from many drops. It also allows our back-up generator to serve all of our buildings.
That ground is probably for the electronics in the transfer switches.
Here is main service. Train room of LION is on the top floor, with those four windows.
ROAR
Lion,
I assumed that you were showing a ground that you added for your own model railroad work.
From your further comments, it appears that the photo is showing the connection of the service’s grounding electrode conductor to the water pipe. My comment, then, does not apply. I am guessing that the photo was shot in the basement, rather than on the top floor.
I do strongly recommend not using a water pipe for a home-made ground. The proper and code-approved method is to connect one’s new ground with the existing grounding system of the building.
As an example of unintended consequences, I saw a building where a plumber had replaced a good bit of the water supply system in the building. He left the previous pipe that had the electrode grounding connection in place. BUT the piece of pipe was about 5 feet long and not connected in any way to the new water system. And that happened when the electrode connection was properly made.
Ed
Correct, the picture was taken in the basement.
On the railroad the ground is simply connected to the electrical system via a plug with only the ground wire connected.
But of course the whole railroad room is in a building that did not have grounding recepticals, but did have metal conduit. I put an extender box on the one outlet in the room and then tested the ground by lighting a 500 W bulb between the HOT and the conduit. It lit up properly and so I figured that the ground was good to go.
Anway, the common ground has no problems as long as it is grounded. If I remove the ground, the floating gremlins take over and cause problems.
ROAR
Primary ground is direct to earth via a ground rod, ring, or plate. A water pipe is considered a secondary ground. That’s because a water pipe does not or may not always remain in contact with the earth for at least ten feet due to corrosion, plumber changing it to plastic, etc. In addition, your water provider has no obligation to provide a good ground for a structure with its pipes so you can’t count on it.
I know that that is not the primary ground. MDU has a good solid ground in the transformer cabinet, we have our own grounds in several places. I do not know why that one was attached to the pipe. Maybe it is the pipe that he is trying to ground. I will suss out that line to see what is connected at the other end.
Water, like electric is our own system. Used to have a well, but now we are on the Southwest Water Project as if we were a city. City of Richardton has its own account and connections to the Southwest system. Our contract specifies water and pressure on demand. The city contract does not, they take a continious flow, but count on their own pumps to move water to the tower, and gravity to move water around the town.
We have a 6" connection to the city main for fire protection, but otherwise we have a 2" line connecting to our pressure tank in the powerhouse.
Back in the 19teens we were the power companay for the town. We continued to generate DC into the 40s and AC into the 60s. Now our new generator produces 100KW as a back-up system. Our typical use is 20-27KW, with 40+KW peak on Sunday when the church is all lit up.
The Richardton Rural Telephone Cooperative is now a big company, but our number (15) is the same as it was back then, they just kept adding new numbers in front of it as they got bigger. Today all phone service in Richarton is fiber optic. No more copper. (Except what I salvagted for the train room.) : )
ROAR
Looks like ground is on wrong side of valve?
It’s not the water that conducts the electricty…
–Randy
Section 250.104 Bonding of Piping Systems and Exposed Structural Steel of the NEC requires:
(my words) all metallic piping systems to be bonded to the service enclosure. This includes water pipes if they are NOT used as a grounding electrode. For example, if you have plastice pipe delivering water to your house, and copper piping inside, it has to be bonded. So, to, by the way is metallic gas piping. And even compressed air piping. And, frequently, the hot water piping in addition to the cold.
Different “authorities” enforce this section differently. As they appear to do for the rest of the code.
Ed
Just code out here.