Surge Suppressor FAQs

Interest is high and questions are fast and furious. Here are some we have received to date:

Where do I hook up the TVS?

Back when we first started selling surge suppression devices, the thought was to add protection - including fuse protection - close to the transformer. Theory was that a problem at the track pulls the current from the transformer. Real life is a problem at the track tends to cause havoc at the tack side of the command control units - so we moved the surge protector and fuse closer to the track. Generally speaking, that's where you want the TVS-4, close to the track. Connection alternatives include:

For a conventional layout:

TVS-4 is connected in line between the transformer and the track in this combination: transformer : TVS-4 / inline fuses / track. (And of course ground wire to house ground.)

For a MTH DCS system:

Option 1 minimal:    TIU / TVS-4 / Fuse / (distribution block if used) /Track

Option 2 better:    TIU / Distribution block / TVS-4 and fuse for each block / Track

Option 3:    If you want additional protection between transformer and track then also use a channel of the TVS-4 here.

For a Lionel TMCC system:

Typical installation is transformer / TVS-4 / Fuse / Track with command signal connected directly to the track common, but signal can go through TVS-4 without degradation.

If using A BPC (Block Power Controller) you'd want the TVS-4 after the BPC.

Same thing with systems with TPCs, it's best to connect the TVS-4 between the TPC and the track.

Wiring note for TMCC:

The surge suppressors were designed with "home-run" wiring in mind. With star pattern layouts (i.e. TMCC) you'll need to make sure that t-off the common so there is one on every channel.

Will your VTS-4 surge suppressor interfere with my TMCC/DCS signal?

Both Mike's Train House DCS™ and Lionel's TMCC signals broadcast through our VTS-4 without any problem. We chose a type of transorb and a transient threshold of 30V to be sure not to cut off or degrade command signals.

What's the extra terminal/wire for on the DTK?

This is a ground wire that needs to be connected to house ground usually at the center screw of your electrical socket or terminal strip (metal version). When the DTK is detects a voltage spike/surge it shunts it to ground.

What's a good ground?

Not to be confused with your transformer "common", below I listed options for a good ground in order:

Building Frame
Dedicated Rod
Cold Water Pipe
Electrical Service Ground
Secondary Electrical Service Ground - i.e. center screw on a electrical wall plate.

I highlighted in blue what will probably be the most commonly used ground for model railroaders, which is a wall plug. Use 10 gauge wire (now available separately) with a spade terminal on the end to connect to the center screw. I use a metal terminal strip rather than the more typical plastic ones and connect to that center screw -which is tied in to the whole house. However, it may not be unusual for a more sophisticated layout to strive for a better ground.

Path of least resistance.....

In the event of a spike or surge we want the voltage to want to go to ground - not to your layout. Because a ground circuit is very low ohms, this becomes the more desirable route for a surge. It's best if the distance to ground is closer than the distance between the transformer and your TIU and/or your layout. But let's be sensible...this is rarely true in our case. Some tricks include making a small, loose loop (couple wraps, nothing crazy) with the wires between the DTK and your layout. Another trick is to use a heavier gauge wire for your ground wire. Again, the less resistance will make this a better path.

Why aren't surge protection devices built into my equipment?

I believe to some extent surge / spike protection is built into most everything. But the expense of quality protection can easily out weight the manufacture cost of the product. A good example is when you buy a desktop computer, it comes with basic software and that's it. After all, the price of most deluxe software programs can well exceed the price of the computer. Another interesting thing is there isn't at this point a "spike protection class" in electronics school. The handful of companies that are really into this consist of select entrepreneurs developing the technology as they go.

Is one TVS enough?

This is an interesting new trend - and it makes sense. If you're operating a large layout the transformer(s) and surge protection devices can be pretty darn far away from the source problem. To speed up reaction time in this cases, customers have been locating their surge protectors closer to the protected blocks - not necessarily right beside the transformer.

Are the in-line fuses necessary?

Yes. Ground faults caused by some derailments or other unfortunate accident are the same as putting a screwdriver across the tracks. Or shorting the wall socket in your house. In these circumstances it is necessary to just shut off power, and fast blow fuses are the fastest, least expensive solution I've found so far. (Note fuses are not nearly as fast for voltage spikes - which is why both levels of protection is best.)

Did you consider circuit breakers instead of fuses?

Yes, we contacted Bussman asking for selection advise and they responded: "We don't really have a circuit breaker solution that would be as fast acting as the fuse you have selected....." Regards, Fusetech

Update - we've added in line circuit breakers responding to popular requests. Still, fuses are the faster solution. Check out CB4-XX for more information.

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