breaker or not to breaker

I use 10 amp automotive mini fuses (one for each of the 4 channels) between the transformer and the TIU.  I get them for about $1 each at an auto parts place or about 30 cents each at my LHS.  The TIU has 15 amp fuses, but I don’t really feel like taking it apart to change them and have never had to.  It’s not unusual for a 10 amp fuse to blow if something derails or if I am not careful when putting a car on an energized track.  I don’t know if a circuit breaker would be fast enough.  I wouldn’t want to risk damage to the TIU or one of the boards in an engine.

Actually, unless it's changed, the TIU has 20A fuses.

An extra circuit breaker can't be all bad, I'd probably have it between the transformer and TIU unless you have a modern transformer with a quality circuit breaker.

I would recommend the circuit breaker, but as GRJ says, put it between transformer and TIU regardless of transformer.  I would not use a fuse, because in the long run it's too expensive.  Use the lowest amp rating that will operate your trains.

I use (7.5 amp) fuses per track circuit. There are (8) track circuits.  In most cases the smallest overload protection will go first regardless of position in the circuit.  

I stand corrected.  The TIU fuses are 20 amps.  Not sure why I thought they were 15.

Do you need a fuse if you are not running power through the TIU?

J Daddy, the issue is that older transformers' circuit breakers may or may not be working properly.  So I would say, yes, to protect your layout and your house, from fire due to overheating wires, transformers, or other components.  I use fuses and breakers in series, the former of a higher rating than the breakers, for reduncancy.  As is noted above, the lowest rated component usually opens first.  You can go through a lot of fuses trying to find a derailment.  I use 5 amp breakers on circuits that rarely have more than 2 locos running at a time, 7.5 on the circuit that often has 3 or 4.  I do not use smoke.  They opften open before the 10-amp breaker in my Z4000, and I've never had the breaker in my postwar Z's open---they are slow, if working at all.

Got it, thanks, I have circuit breakers from the transformer to track, but did not know if I hook up the TIU in passive mode, do I need breakers or fuses between the track and TIU.

For a PW transformer, I always like modern breakers on the outputs, makes me sleep better at night.

do I need breakers or fuses between the track and TIU.

You never need breakers between the TIU and the track to protect the TIU. Placing them in that position won't protect the TIU at all, whether it's in normal or Passive modes.

 I use as above with 7.5 amp glass "fast blow" fuses. The fuse closest to the "incident" always blows and leaves the rest of the system untouched. I pay 1.89 for a 5 pack of fuses.

thank you for the feed back i use a z4000 tiu distribution blocks with lite  blubs i have sorted out a few boards do to shorting out stuff on the track ex rolling stock derailments you know i was hoping like a 10 amp push button braker might give some ex protection  yes no maybe ?

Jack, I suggest you see what amperage you draw, using the ammeters on the Z4000.  Then use a breaker slightly above the highest normal draw.  That will give max protection.  For a 10+amp short, the Z4000 internal breaker is hard to beat speed-wise.

You should also note that thermal breakers, of which a vast majority of trans transformers use, will actually take some time to trip at just above their rated current, usually many seconds to even a couple minutes.

I like the idea of breakers and higher rated fast-blow fuses for maximum protection.  You can be fairly sure that above the rated current the fuses will go pretty quickly.

You can be fairly sure that above the rated current the fuses will go pretty quickly.

Wrong.  Check the blow time charts the major fuse manufacturers have on their web sites.

Check the timing on the thermal circuit breakers, and you'll see the fuses should certainly go before they open, even if they're rated somewhat lower than the fuses.

I stand by my statement as made.  Fuses can withstand small (10-20%) overloads for a long period of time before blowing. 

I never mentioned thermal breakers.  With a thermal, use the smallest rating that will operate your circuit.

The reason I mention thermal breakers is that is the type used on virtually all of the transformers, with the exception of the Lionel PH180 and the Lionel ZW-L.  All of the MTH transformers use thermal breakers, and all of the ones I see recommended in various threads are thermal breakers as well.  The only non-thermal breaker that has been discussed that I can remember is the PSX-AC product.

jack kolsterman,

    Do as Barry advises and put the 10 Amp resettable breakers between your Transformer and the TIU, I even use them with my Z4K's, and always with my ZW's & KW's also.  I have been using the Scott type resettable breakers for many years, you can now purchase them thru one of our OGR Sponsors, Train Electrics.  These resettable breakers work great and are easy to install and use, they come in a little 4 bank set.

PCRR/Dave

RJR & GRJ,

I've often thought about using thermal fuses. Could they be used in place of quick blow or a circuit breaker? I thought I would ask since the topic is fuses......Thank you! 

All fuses are thermal.  The current flowing through the filament, which has resistance, heats the filament.  The more current, the hotter it gets, until it melts.

I installed 4 amp push button resetable circuit breakers between my Z4000 and the TIU.  I have a scale mile of track and can run my Big Boy with smoke and four lighted passenger cars, a 4400 pulling 20 cars with a lighted caboose and a GP38 pulling 10 cars with a lighted caboose all on the same track.   

jmiller, I'm curious.  What do the Z4000 ammeters read?

Are you talking about something like a PTC?  Those are certainly no faster than a standard circuit breaker, and slower than a fuse in most cases.  If you require really fast acting circuit protection, electronics is the way to go.

Guns,

   As usual you are absolutely right, however my 10 Amp Scott Type Breakers have been working perfect for many many years.  When they make the electronic breakers dirt cheap then I might consider changing.

PCRR/Dave

GRJ,

I'm confused, I guess. I was thinking about one type that once tripped it will reset itself when cooled. All of this almost instantly. An example would be if a car jumped the track and tripped the breaker, it would reset itself automatically once the condition is corrected. Maybe, I'm just dreaming?

Pappy,

    Hennings has those new type auto re-settables, I do not think Guns is talking about them however.

PCRR/Dave

Truthfully, I am NOT a fan of self-resetting breakers.  When I have a fault, I want to be able to look for it and correct it, not have my power source keep hammering the short with more power!

There are other self-resetting breakers as Dave notes, I just don't happen to endorse them.  The PTC takes a few seconds to cool and reset as a rule.

For example, i inadvertently left a harbor freight dvm test leads(on the 200 ohm scale)

connected across my 2 rail track..forgot about it and powered up my TIU. The 7.5 amp fast blow blew immediately. Here's the kicker.. the meter survived as well.

Truthfully, I am NOT a fan of self-resetting breakers.  When I have a fault, I want to be able to look for it and correct it, not have my power source keep hammering the short with more power!

I absolutely agree with you, John.

Pappy, but until you find the short, the current will keep turning on & off, which can cause problems with equipment on the layout.

John, RJR & Dave,

I wouldn't dare use anything but fast-trip breakers. Which I've used for the past twenty years. One of the buyers that my children sold one of my layouts to contacted me asking questions. I told him to stay with what was on my control panel.

One good thing though. I found out who bought one layout and what he paid. My children wouldn't tell me. Now, I'll find out who bought my standard gauge layout. Thank you, for all your help. 

I'm using one Z4000.  I have a double track main with two separate loops that measure one scale mile in length. 

Here is what I was running.  Track one.  MTH Premier AC4400 pulling 17 mixed MTH Premier freight cars with two lighted cabooses.  Smoke unit on high, track speed 25 smph.  Ammeter reading 2.8.

Track two.  MTH Premier Big Boy with three lighted passenger cars and one reefer.  Smoke unit on high, track speed 25 smph and MTH Premier GP35 with three lighted cabooses.  Smoke unit on high, track speed 25 smph  Ammeter reading 3.0.

The amps drop when I turn off the smoke units which I try to keep off as the smoke bothers my sinuses.

OK, I was reading your post to say you had the 3 trains running on a single 4-amp breaker.

I have in the past, I'll go back down and do a little switching to get all three on the same line.

OK, I just ran everything in the above post on one track.  I could only get them up to 15smph as I only have one controller.  Here is what I was running.  MTH Premier AC4400 pulling 17 mixed MTH Premier freight cars with two lighted cabooses.  MTH Premier Big Boy with three lighted passenger cars and one reefer.  MTH Premier GP35 with three lighted cabooses.  At least one smoke unit was on.  Amp gauge was bouncing between 3.8 and 4.0.  When I blew the whistle on the Big Boy the gauge jumped up to 4.8

Gentlemen,

   Actually I am with Guns on this one, I like the manual resettable breakers, preferably the Scott type in the 4 bank, they work great all the time and are very easy to use.  They pop up, you turn the power off and push the breaker button back down, and go back to running.

PCRR/Dave

thank you all for your input lots of good info do you guys know where i could look up the scotts beracker tryed goggleing scotts not much luck thanks again jack k

These are the type I bought.  I mounted then in a plastic receptacle box by drilling a 3/8 inch hole in the bottom.  Someone will come along and tell you where they got something cheaper, but this is what I found and they were cheaper then the ones a member of the train club I belong to was selling.  I have two loops and installed the box with the breakers between the TIU and Z4000.

I posted this information on another thread.  Check out these.  I bought two, one for each side of my Z4000,  $18 each and the plastic box $.69

http://www.alliedelec.com/sear...il.aspx?SKU=70128886