TVS and Fast Acting Circuit Breaker help

After reading all the recommendations in this forum I added both.  I grabbed the fuse holder and glass fuse at autozone.  TVS from eBay.  I haven’t had a problem since but sure worth the piece of mind in my opinion.

once you did that did it help with sparks during derailments?

There's no real help for some sparks during most derailments, when you connect the rails together, you get sparks.  The issue really is, how well does the circuit protection stop the current flow when this short happens.  The real message here is to work on the trackwork to minimize any issues of derailments.  That's normally not that difficult with O-gauge 3-rail, it's pretty forgiving of less than perfect trackwork.

GRJ should I add more protection than just what the z4000 provides?

I don't think that will do much for sparks during derailments.  If you want the fastest acting circuit protection, you'd probably want to consider something like the PSX-AC board on each power feed.

Ok thank you, so I don’t need to add the extra breakers or TVS to my loops?

A TVS isn't a bad idea at each track feed.  If you have MTH DCS with the TIU, each channel has a TVS on the output.

any type of TVS you recommend, I don’t have a TIU, I just have legacy.

1500W 33.3V TVS at Digikey

does that go on the terminal block that comes from the transformer?

That's a good spot, the TVS goes right across the track feed from hot to common.

Thank you for all the help

Casper, I installed a TVS on every track feed and a PDX-AC on each of my two power feeds, just what John posted.  The PDX-AC is certainly fast acting.  I haven't fried anything since the installations. 

OK. I have a Z-4000 going to a TIU. I jumper my power wires from the Fixed inputs to the Variable inputs. I set the Variable inputs to Fixed. I power my TIU externally with a Z-1000. I use all 4 outputs on the TIU. Where exactly would the PSX-AC's go? Between the Z-4000 and TIU or after the TIU?

The PSX-ACs go between each Z4000 output and each TIU input.

Mark, thank you. Just curious  but why not between the TIU and track? Not being that electrically educated I'd like to know what happens electrically, both voltage and amperage, to the circuit and to the dc signal the instant I have a derailment and my wheels cause a short. Don

Having the PSX-AC before the TIU eliminates any possibility of it affecting the DCS signal.

GRJ, thanks for the info,

Don

Trestleman1, John is right.  Don't feel bad in the least.  I worked in electronics for 43 years, and you would think I would have thought of John's reason.  However, I didn't and first connected them after the TIU.  I was in a long discussion on the topic a few months ago and changed mine to match what John said.