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Electrical Blocks

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  • Member since
    January 2021
  • 13 posts
Electrical Blocks
Posted by arp22 on Tuesday, February 16, 2021 10:05 AM

New to DCC, I am building a new 4x8 N scale layout, one user, up to 3 locomotives. Will be mostly mainline with one yard and a couple of spurs. Advice on whether I need to make electrical blocks and how many? Thanks.

  • Member since
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  • From: Shenandoah Valley
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Posted by BigDaddy on Tuesday, February 16, 2021 5:07 PM

You may or may not be confused between power blocks and electrical blocks.

A power block has it's own input and keeps running is there is a short in another power block.  If you had an around the room empire requiring multiple operators, you would want multiple power blocks.

There are three reasons to have electrical blocks in DCC

  1. Some low end sound decoders automatically start up when you power up the layout.  AFAIK you can't change CV's to stop that.  It's annoying.
  2. There is a concern that if you have enough locos, they could put a power drain on a starter system to max out the power output even though they are parked on sidings.
  3. It makes shorts easier to isolate.  In a 4x8 layout I think that value is pretty dubious.  If you are a lone wolf, you know the short occured where your loco ran through an improperly set switch. 

Henry

COB Potomac & Northern

Shenandoah Valley

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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Tuesday, February 16, 2021 5:53 PM

I agree that such a small area probably does not need blocks.

One side discussion we've had in a number of threads concerns the real need to break up large layouts into blocks when there is a lot of power available, to limit the power in any single block to prevent damage.  A large layout with perhaps 8 amps of power would be better subdivided with breakers limited to 2 or 3 amps each so that full 8 amps wouldn't be crossing through a short and causing damage.

It takes an iron man to play with a toy iron horse. 

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  • From: Dearborn Station
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Posted by richhotrain on Tuesday, February 16, 2021 5:56 PM

Henry and Mr. B. have already given you some good information.

Let me add a thought or two.

A power block, protected by its own circuit breaker, is called a power district in DCC. A separate power district will isolate that section of track from the rest of the layout. Any short that occurs inside the power district will not affect any track outside of the power district.

So, while your layout is small, controlled by a single operator, you could turn the yard into its own power district. That way, a short in the yard will not stop operation of your mainline.

Rich

Alton Junction

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Posted by riogrande5761 on Wednesday, February 17, 2021 9:06 AM

Lastspikemike

It can be handy to have an off switch to cut power to a siding or two in order to park a locomotive. For mainline you only need power districts for large layouts or for the three aspects noted above. 

 

 
I need to do that.  Can anyone recommend some economical switches to cut power to DCC blocks?

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by wjstix on Wednesday, February 17, 2021 9:26 AM

riogrande5761
Can anyone recommend some economical switches to cut power to DCC blocks?

I just use old school Atlas Connectors.

https://shop.atlasrr.com/p-4779-connector.aspx

Keep in mind you will still need to isolate any reverse loops you have, and you might want to think about setting up blocks now when laying track in regards to someday adding signalling with track detection circuitry.

You can also use a DPDT switch to set up one electrically isolated block of track to use as a programming track. It can be nice to be able to test run an engine, then change a CV and test it some more, without having to keep picking it up and moving it to an off-the-layout programming track.

 

Stix
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    June 2007
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Posted by riogrande5761 on Wednesday, February 17, 2021 9:33 AM

I would think a DPST would work for killing the DCC power/signal to a block, such as a staging yard block.  Maybe a DPDT could be useful for isolating a track for programming.

Rio Grande.  The Action Road  - Focus 1977-1983

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Wednesday, February 17, 2021 3:22 PM

riogrande5761
I need to do that.  Can anyone recommend some economical switches to cut power to DCC blocks?

I would suggest to get a switch that feels correct to you. Any single pole single throw (SPST) switch will work. You just need to turn off one rail.

I prefer full sized industrial toggles just because of the tactile feel they have.

The cost is minimal for just a few switches, so buy what feels right to you.

-Kevin

Living the dream.

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    December 2015
  • From: Shenandoah Valley
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Posted by BigDaddy on Wednesday, February 17, 2021 5:27 PM

riogrande5761
Can anyone recommend some economical switches to cut power to DCC blocks?

Richhotrains has a thead about getting rid of his switches for tortoises.  Check it out and pm Rich

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    September 2004
  • From: Dearborn Station
  • 24,014 posts
Posted by richhotrain on Wednesday, February 17, 2021 5:38 PM

BigDaddy
 
riogrande5761
Can anyone recommend some economical switches to cut power to DCC blocks? 

Richhotrains has a thead about getting rid of his switches for tortoises.  Check it out and pm Rich 

Those switches that I have are DPDT toggle switches. There is no point in sending me a PM because my PM feature hasn't worked in two months thanks to the indifference of Kalmbach who ignores my emails and pleas for help.

Rich

Alton Junction

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