Circuit breaker Kit


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This is a brand new product designed to protect your rolling stock from damage due to short circuits in your layout.

Here is the story of its development

Recently we were fortunate to purchase over 300 transformers, and are in the process, of checking, refurbishing, and in some cases modifying to make them more appropriate to modern times.

One of the first order in our refurbishing is to change the antiquated circuit breaker, to a much better-quality unit that works much faster than the original breakers. The original breakers that were installed by Lionel and other manufactures were put in circuit for one purpose only. That was to protect the transformer from self-destructing. They were not designed to protect the outputs of their transformers. Yes, they normally will open should you have a short circuit due to a derailment or other ills. The problem is that by design they take way too long to open. Our new circuit breakers we install work many times faster than the originals, but by the nature as to where they are in the transformers circuit, while much faster than the old ones, they do not provide very rapid protection to the outputs of the transformers.

There is a lot of discussion in the O gauge world, that you should not use any transformer that has not been designed more than 10 years ago, for fear of damaging the solid-state equipment built in some of the rolling stock. I understand the newest bigger Lionel transformers have corrected these ills. Only problem is they cost close to to $1000, and their reliability has not been good.


To fix these issues with older transformers, we found a source for some really fast acting circuit breakers that will open instantly with any short circuit.  They will continue to conduct with an 8 amp draw, but will open with a partial short circuit which will raise the current draw more.

This kit is designed to be installed between the transformer outputs and  the center rails (or if you wish to an accessory output) of your layout.   The pictures below are an example as to how they can be used. We used a ZW and KW as an example for you. The way the pictures show, the way they work is to protect the outputs they are hooked up to which typically are used to run the trains. The balance of the outputs are still protected by the transformers internal circuit breaker.

This kit will work with virtually any train transformer. If you have for example an older smaller transformer, the kit will work great in those too. Any of these older style transformers we sell and or refurbish the kit is not necessary because we have already installed the new breakers in lieu of the original factor supplied. These earlier lower power transformers (under 130 watts) our breakers we install work fine, by themselves.

The LED’S mounted on the top will light when the internal circuit breaker(s) open. This will then indicate which side has an issue, so you can isolate the problem causing the breaker to open.


We have tested these new breakers every way possible and they work great. So well that on all of our smaller transformers we sell (under 135 watts) we now permanently install these new breakers inside these transformers.  For Transformers larger than 135 watts, it is better putting installing our own heavier duty units. Why? Because the larger transformers are so powerful, they would be blowing when not necessary. We are now offering the kit to buyers of our KW’s / ZW’s, at a very reasonably priced option.

Complete wiring instructions are included.