Date   
Re: DCC Wiring - Can it cause a fire?

Carl
 

Hi Gang:

Years ago my electric water heater was struck by lightening. This burned through the heating element and allowed electricity in to the water. Nothing happened until I took a shower and the thermostat turned the water heater on. The water limited the current to less than the 30 amps the breaker allowed, but this was enough to melt the insulation on the wires to the water heater. I could smell the melting plastic and turned the power off. Then I put in a gas water heater.

So others are right: the power supply has to have the amps to trip the breakers. And the breakers should be sized to protect the wire from overheating if shorted, not the size of the power supply or booster. Each step in the power supply chain should have its own protection. Plus the wires attached to exposed metal rails and anything can short the circuit. Even moist ballast could carry current. I installed a 220 volt outlet once that unknown to me had been soaked in water for too long. When I turned on the breaker the outlet caught on fire shooting out flames, but didn't trip the breaker. I was there so I quickly turned the breaker off.

Carl.

Re: DCC Wiring - Can it cause a fire?

Thomas
 

Rob
DCC does not have a lot to do with it. Power is power. A short circuit in a DC layout could generate the same amount of power just as easy.
When is the last time you heard of a DC layout causing a fire. If the wiring is under sized and you get a short, the wires could heat up and
cause a fire without tripping a fuse or circuit breaker. This is why fuses/circuit breakers are selected to protect the wire. The wire should be
selected to handle the maximum current. Too many people select the fuse/ circuit breaker according to what the power supply can put out
and don't pay any attention to wire size. This is dangerous!
Tom

From: "Robmorrison@..." <Robmorrison@...>
To: WiringForDCC@...
Sent: Saturday, January 18, 2014 2:32 PM
Subject: [WiringForDCC] DCC Wiring - Can it cause a fire?

 
A friend told me that he knew of a situation where a DCC system left on heated up the wires, especially the track feeders, so that a fire started all along under the track. He said the fire official told them that it looked like the fire was started and spread along the line of the track. He then went on to say that at 5 amps and 16 volts, we have about 80 watts going, quite a bit more than the average soldering iron, hence the fire potential. It is not known if there were separate circuit breakers.

I am a bit skeptical, but wondered if anyone on this list knows about this possibility.


Re: DCC Wiring - Can it cause a fire?

David Heine <davesn3@...>
 

 

In general, a circuit breaker doesn’t know the difference between 5 amps of load, 5 amps caused by a short with the current limited by inadequate wiring, or 5 amps caused by a higher impedance short that limits the current to 5 amps by itself.  In this case, I would suspect a short with inadequate wiring or some sort of higher impedance short.

 

I knew better, but on a previous layout, I let my track laying get ahead of my wiring.  I had about 25’ of track (50’ of Code 70 rail) beyond the last set of track feeders.  I was test running an engine, it derailed and caused a short.  Because of the resistance of all the rail, the current level was held below the value for the protection to trip the power (5A).  I had to shut off the power manually.  The short was on long enough to melt the Kadee coupler box on the tender of a brass locomotive.

 

Dave Heine

Easton, PA

     

 

 

Re: DCC Wiring - Can it cause a fire?

Bill><>
 

WOW!
Thanks for that tid-bit!!!!
Bill Kozel
 

Sent: Monday, January 20, 2014 2:28 PM
Subject: RE: [WiringForDCC] DCC Wiring - Can it cause a fire?
 
 

In general, a circuit breaker doesn’t know the difference between 5 amps of load, 5 amps caused by a short with the current limited by inadequate wiring, or 5 amps caused by a higher impedance short that limits the current to 5 amps by itself.  In this case, I would suspect a short with inadequate wiring or some sort of higher impedance short.

I knew better, but on a previous layout, I let my track laying get ahead of my wiring.  I had about 25’ of track (50’ of Code 70 rail) beyond the last set of track feeders.  I was test running an engine, it derailed and caused a short.  Because of the resistance of all the rail, the current level was held below the value for the protection to trip the power (5A).  I had to shut off the power manually.  The short was on long enough to melt the Kadee coupler box on the tender of a brass locomotive.

Dave Heine

Easton, PA

    




Madogbill><>

Re: DCC Wiring - Can it cause a fire?

Vollrath, Don <dvollrath@...>
 

Poor connections, too small a wire to support an overload and outright arcing that causes excess heat while limiting current to less than the protective fuse or CB trip point is what allows most electrical fires to get started. Houses, industry, model RRs… makes no difference.

So, Yes, there is a potential of starting a fire. As others have pointed out 5 amps x 16 volts (actually more like 12-14) under the right/wrong conditions can cause 60-80 watts of pure heat, somewhere on your layout. But there are three possible conditions here, neither of which will be positively prevented by circuit breakers. 1) If the malfunction current path includes a relatively high resistance (something greater than about 2.75 ohms), call it a partial short if you wish, that causes less than the full 5 amps to flow, a full 60-80 watts may be concentrated at that location causing lots of heat. Since current is limited to be less than the circuit breaker trip point, it will never trip or automatically shut down. A short circuit between two power pick-up trucks connected together with small gage wire can rapidly get hot enough to melt plastic. A poor solder joint track or puny feeders may provide the current limiting resistance. 2) If the mentioned malfunction causes sparking and current is somehow being limited by undersized wiring, the sparking arc itself can be hot enough to start paper, plastic and wood on fire. (think welding) 3) Notice that even with current limiting light bulbs, a good solid short at the load end will cause the bulb to light up quite brightly and the glass surface can soon become hot enough to burn fingers or start a paper fire.

 

However, if you have followed the principles of wiring for DCC… a) You will use robust wiring with plenty of track droppers and verify that a short anywhere on the track will cause the circuit to become interrupted by the booster protective device or electronic CB. b) Always follow the manufacturer’s recommendations when it comes to selecting, using or connecting a power supply for/to a booster or other accessory. AND c) Never leave the DCC system turned on while totally unattended, with or without locos running. Pay attention… Stuff happens.

 

DonV

 

From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of Robmorrison@...
Sent: Saturday, January 18, 2014 1:33 PM
To: WiringForDCC@...
Subject: [WiringForDCC] DCC Wiring - Can it cause a fire?

 



A friend told me that he knew of a situation where a DCC system left on heated up the wires, especially the track feeders, so that a fire started all along under the track. He said the fire official told them that it looked like the fire was started and spread along the line of the track. He then went on to say that at 5 amps and 16 volts, we have about 80 watts going, quite a bit more than the average soldering iron, hence the fire potential. It is not known if there were separate circuit breakers.

 

I am a bit skeptical, but wondered if anyone on this list knows about this possibility.

 

My own On30 layout, which is only 12-feet by 12-feet, is separated into four districts, each protected by a DCC Specialties circuit breaker.  Probably overkill, but I feel better about it that way.

 

I would think that the circuit breakers would handle all or most shorts.  But what could be the cause of drawing enough power to heat things up that much without triggering any overload protection?  Unless the power station portion of the DCC system' s overload protection failed, I cannot envision the above problem.

 

Thnaks for any insights you may have.

 

Rob Morrison




Re: DCC Wiring - Can it cause a fire?

Robert Heroux
 

Lets all face it... When not running your railroad.... Turn the power off..... I do...

Just my two cents....

Bob

On Jan 20, 2014, at 2:07 PM, madog <madog@...> wrote:


WOW!
Thanks for that tid-bit!!!!
Bill Kozel
 
Sent: Monday, January 20, 2014 2:28 PM
Subject: RE: [WiringForDCC] DCC Wiring - Can it cause a fire?
 
 

In general, a circuit breaker doesn’t know the difference between 5 amps of load, 5 amps caused by a short with the current limited by inadequate wiring, or 5 amps caused by a higher impedance short that limits the current to 5 amps by itself.  In this case, I would suspect a short with inadequate wiring or some sort of higher impedance short.

I knew better, but on a previous layout, I let my track laying get ahead of my wiring.  I had about 25’ of track (50’ of Code 70 rail) beyond the last set of track feeders.  I was test running an engine, it derailed and caused a short.  Because of the resistance of all the rail, the current level was held below the value for the protection to trip the power (5A).  I had to shut off the power manually.  The short was on long enough to melt the Kadee coupler box on the tender of a brass locomotive.

Dave Heine

Easton, PA

     




Madogbill><>







Robert Heroux
ACCU-LITES, Inc.
Your DCC Center
118 S. Main St. STE 5
Wauconda, IL 60084

Phone: 847.224.7914
FAX: 847.487.2089
NMRA Member # 143811


Re: DCC Wiring - Can it cause a fire?

Flash Gordon
 

Of course you have to install the bulbs properly so they do not touch anything. . And when they light up ... even a little ... you know you have a problem somewhere. They are hard to miss when you turn the lights off to leave the basement.

At 04:04 PM 1/20/2014, you wrote:

3) Notice that even with current limiting light bulbs, a good solid short at the load end will cause the bulb to light up quite brightly and the glass surface can soon become hot enough to burn fingers or start a paper fire.



DonV

Re: DCC Wiring - Can it cause a fire?

george hohon3
 

Re-wired the new layout with a lighted, main power switch. Located at the door entering the layout. One look at that switch and you know immediately if the room is "powered" or not. Single best improvement I ever made to a layout. I never leave the area without knowing.

George

On Jan 20, 2014, at 2:28 PM, "rheroux@..." <rheroux@...> wrote:

Lets all face it... When not running your railroad.... Turn the power off..... I do...

Just my two cents....

Bob

On Jan 20, 2014, at 2:07 PM, madog <@BillK> wrote:


WOW!
Thanks for that tid-bit!!!!
Bill Kozel

From: David Heine
Sent: Monday, January 20, 2014 2:28 PM
To: WiringForDCC@...
Subject: RE: [WiringForDCC] DCC Wiring - Can it cause a fire?




In general, a circuit breaker doesn’t know the difference between 5 amps of load, 5 amps caused by a short with the current limited by inadequate wiring, or 5 amps caused by a higher impedance short that limits the current to 5 amps by itself. In this case, I would suspect a short with inadequate wiring or some sort of higher impedance short.


I knew better, but on a previous layout, I let my track laying get ahead of my wiring. I had about 25’ of track (50’ of Code 70 rail) beyond the last set of track feeders. I was test running an engine, it derailed and caused a short. Because of the resistance of all the rail, the current level was held below the value for the protection to trip the power (5A). I had to shut off the power manually. The short was on long enough to melt the Kadee coupler box on the tender of a brass locomotive.


Dave Heine

Easton, PA








Madogbill><>
<comp2small.png>





Robert Heroux
ACCU-LITES, Inc.
Your DCC Center
118 S. Main St. STE 5
Wauconda, IL 60084

Phone: 847.224.7914
FAX: 847.487.2089
NMRA Member # 143811

http://www.acculites.com

Re: DCC Wiring - Can it cause a fire?

Flash Gordon
 

Good idea, I am doing the same.

Ed S

At 06:35 PM 1/20/2014, you wrote:


Re-wired the new layout with a lighted, main power switch. Located at the door entering the layout. One look at that switch and you know immediately if the room is "powered" or not. Single best improvement I ever made to a layout. I never leave the area without knowing.

George

Sent from my iPad

On Jan 20, 2014, at 2:28 PM, "rheroux@..." <rheroux@...> wrote:

Lets all face it... When not running your railroad.... Turn the
power off..... I do...

Just my two cents....

Bob

Re: DCC Wiring - Can it cause a fire?

Robert Morrison <Robmorrison@...>
 

Good idea about the lighted switch for layout power circuits. I did this at my old home, but not yet at the new one.
Of course, since most of my locomotives have steam sound decoders, there is enough noise to alert me when I leave.
Nevertheless, my next project is to get a circuit with a lighted switch at the entrance to the layout.

I use 20 AWG wire for the drops to every piece of rail, no drop is more than 12 inches long.
Joiners are for rail alignment only.
Main power bus is 12 AWG.
All sections of the layout do trigger the circuit breakers when shorted with a quarter or screw driver.

An idea:
After the layout power is on for a while, go around feeling the wires, especially the drops and solder joints for heat build up.
That might tell you if there is a greater potential for fire.

What do you think?

Rob

Re: DCC Wiring - Can it cause a fire?

Mark Gurries
 


On Jan 21, 2014, at 11:52 AM, Robert Morrison wrote:

Good idea about the lighted switch for layout power circuits. I did this at my old home, but not yet at the new one.
Of course, since most of my locomotives have steam sound decoders, there is enough noise to alert me when I leave.
Nevertheless, my next project is to get a circuit with a lighted switch at the entrance to the layout.

I use 20 AWG wire for the drops to every piece of rail, no drop is more than 12 inches long.
Joiners are for rail alignment only.
Main power bus is 12 AWG.
All sections of the layout do trigger the circuit breakers when shorted with a quarter or screw driver.

Excellent.

An idea:
After the layout power is on for a while, go around feeling the wires, especially the drops and solder joints for heat build up.
That might tell you if there is a greater potential for fire.

The only time you will get heat is if there is a short circuit that fails to trip any DCC circuit breaker or booster.   Hence the purpose of the coin short circuit test which makes sure the resistance in the wiring is low enough.

If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.


Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com



Re: DCC Wiring - Can it cause a fire?

Steve Haas
 

<<If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.>>

 

A local layout has hand laid track and turnouts with powered frogs.  The original track layers and electricians were not too careful about where they cut the gaps beyond turnouts.  We’ve lost the side frames of two different engines to excessive heat when the front wheel set of the engines spanned the gap that isolated the frog from the yard track. 

 

Good construction minimizes a host of errors – keep those gaps inside the fouling point of your turnouts and equipment and it will reduce the number of problems due to shorts by reducing the possibility of shorts.

 

Best regards,

 

 

Steve Haas

Snoqualmie, WA

 

 

DCC Track Design for review

Chuck Stiles
 

Hi I'm new to the group and DCC but not to the hobby
Its been over 30 years since I built my last layout (a lot has changed since then)
I have been doing a lot of reading & research. I designed a new layout 5 x 8'  the table is built and ready to go (you can see it in the FILES section) "Final Layout for Review" 
I am proficient with auto cad so after I tried some of the available free programs like Any Rail I decided to do it in autocad so I can get may track spacing and radius geometry correct.
I have Purchased Peco electrofrog turn out switch Peco 100 Flex Track its going over an old school cork roadbed and ballast
I have purchased tortoise switch machines as well
I built the Walthers Turntable and its ready for install
The uploaded drawing shows my proposed track layout with isolator locations track feed locations and block identification
I plan on wiring the elecrofrog thru the tortoise as per many online recommendations I have read  
The purchase of the other DCC controls I have not fully decided on, I am planning on building a fascia control panel for switch control as well as control from a handheld throttle. In the future I would like to experiment with PC control using JMRI software (but one step at a time).
I'm welcoming anyone to look at my plan and see if I may have over looked something thus far before a start making things permanent. 
There is a reversing section across the middle that I had concerns about wiring a reversing module

Thanks
Chuck Stiles
NJ

Re: DCC Wiring - Can it cause a fire?

Bob <rehandjr@...>
 

Hi Steve,

Are you suggesting gaps closer to or farther from the frog?  Could you explain what you mean with a little more detail? Or point us to a diagram or discussion.

Thanks!

bob

<<If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.>>

 

A local layout has hand laid track and turnouts with powered frogs.  The original track layers and electricians were not too careful about where they cut the gaps beyond turnouts.  We’ve lost the side frames of two different engines to excessive heat when the front wheel set of the engines spanned the gap that isolated the frog from the yard track. 

 

Good construction minimizes a host of errors – keep those gaps inside the fouling point of your turnouts and equipment and it will reduce the number of problems due to shorts by reducing the possibility of shorts.

 

Best regards,

 

 

Steve Haas

Snoqualmie, WA

 

 

10 amp booster Re: DCC Wiring - Can it cause a fire?

Bill><>
 

 
What would the ohms be on a 10 amp booster?
I’m in 2 rail O Scale
Bill Kozel
 

From: Steve Haas
Sent: Tuesday, January 21, 2014 11:52 PM
Subject: RE: [WiringForDCC] Re: DCC Wiring - Can it cause a fire?
 
 

<<If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.>>

A local layout has hand laid track and turnouts with powered frogs.  The original track layers and electricians were not too careful about where they cut the gaps beyond turnouts.  We’ve lost the side frames of two different engines to excessive heat when the front wheel set of the engines spanned the gap that isolated the frog from the yard track. 

Good construction minimizes a host of errors – keep those gaps inside the fouling point of your turnouts and equipment and it will reduce the number of problems due to shorts by reducing the possibility of shorts.

Best regards,

Steve Haas

Snoqualmie, WA


Madogbill><>

Re: 10 amp booster Re: DCC Wiring - Can it cause a fire?

Mark Gurries
 

V = I * R

Ohms law re-writen to solve for ohms

R = V / I

The equation is setup like this:

Ohms(Wiring) = V(track) / I(booster)

For the 10Amp booster, I(booster) = 10A and Vtrack = 16V (Factory setting)

Ohms = 16V / 10A = 1.6 Ohms per advertised specifications.

However in practice the 10Amp booster puts out close to 12Amps  (Production design margin to guarantee 10amps) which mean the actual real value is closer to 1.3 Ohms.

This is the maximum resistance value one can tolerated from one track terminal on the booster out and around the layout all the back to the other terminal of the same booster.  Your layout wiring should make sure it is less than this value.  Hence the quarter test does just that.  If a short circuit between the rails does not shutdown the booster, you have a wiring problem with to much resistance which in this case means you have more than 1.3 Ohms.




On Jan 22, 2014, at 7:00 AM, madog wrote:



 
What would the ohms be on a 10 amp booster?
I’m in 2 rail O Scale
Bill Kozel
 
From: Steve Haas
Sent: Tuesday, January 21, 2014 11:52 PM
Subject: RE: [WiringForDCC] Re: DCC Wiring - Can it cause a fire?
 

<<If there is a highly resistive connection somewhere in the wiring that is more than about 2.8 ohms when using a 5Amp booster and there is a short circuit on the track,  that resistive point is where all the heat will be because the booster will not have shutdown but instead deliver full power.>>

A local layout has hand laid track and turnouts with powered frogs.  The original track layers and electricians were not too careful about where they cut the gaps beyond turnouts.  We’ve lost the side frames of two different engines to excessive heat when the front wheel set of the engines spanned the gap that isolated the frog from the yard track. 

Good construction minimizes a host of errors – keep those gaps inside the fouling point of your turnouts and equipment and it will reduce the number of problems due to shorts by reducing the possibility of shorts.

Best regards,

Steve Haas

Snoqualmie, WA


Madogbill><>



Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com



Re: DCC Track Design for review

Brian Eiland
 

How do you find that "FILES" section, and your "Layout for Review" ??


On Wed, Jan 22, 2014 at 6:08 PM, Chuck Stiles <capnchuck@...> wrote:
 

Hi I'm new to the group and DCC but not to the hobby
Its been over 30 years since I built my last layout (a lot has changed since then)
I have been doing a lot of reading & research. I designed a new layout 5 x 8'  the table is built and ready to go (you can see it in the FILES section) "Final Layout for Review" 
I am proficient with auto cad so after I tried some of the available free programs like Any Rail I decided to do it in autocad so I can get may track spacing and radius geometry correct.
I have Purchased Peco electrofrog turn out switch Peco 100 Flex Track its going over an old school cork roadbed and ballast
I have purchased tortoise switch machines as well
I built the Walthers Turntable and its ready for install
The uploaded drawing shows my proposed track layout with isolator locations track feed locations and block identification
I plan on wiring the elecrofrog thru the tortoise as per many online recommendations I have read  
The purchase of the other DCC controls I have not fully decided on, I am planning on building a fascia control panel for switch control as well as control from a handheld throttle. In the future I would like to experiment with PC control using JMRI software (but one step at a time).
I'm welcoming anyone to look at my plan and see if I may have over looked something thus far before a start making things permanent. 
There is a reversing section across the middle that I had concerns about wiring a reversing module

Thanks
Chuck Stiles
NJ


Re: DCC Track Design for review

Paul O
 

Railandsail, go to the WiringForDCC Yahoo group; on the left side, click on FILES.

The first half of that section is folders and the second half is individual files.

Scroll down until you come to "Layout for Review".

 

Paul O

 

From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of railandsail
Sent: Wednesday, January 22, 2014 10:41 PM
To: WiringForDCC@...
Subject: Re: [WiringForDCC] DCC Track Design for review

 

 

How do you find that "FILES" section, and your "Layout for Review" ??

Re: DCC Track Design for review

Paul O
 

Chuck, it looks like a good plan.

One question: It looks like you have about 25 separate blocks. What is you plan for these blocks?

n  Individual circuit breakers?

n  Auto light bulbs?

n  Grouping them to a terminal block for troubleshooting ease?

 

The reverse loop shouldn’t be a problem so long as the isolated section is longer than any train you plan to run thru it.

 

Do you plan to be a lone operator or have multiple operators?

 

Paul O

 

 

From:  Chuck Stiles

Hi I'm new to the group and DCC but not to the hobby

Its been over 30 years since I built my last layout (a lot has changed since then)

I have been doing a lot of reading & research. I designed a new layout 5 x 8'  the table is built and ready to go (you can see it in the FILES section) "Final Layout for Review" 

I am proficient with auto cad so after I tried some of the available free programs like Any Rail I decided to do it in autocad so I can get may track spacing and radius geometry correct.

I have Purchased Peco electrofrog turn out switch Peco 100 Flex Track its going over an old school cork roadbed and ballast

I have purchased tortoise switch machines as well

I built the Walthers Turntable and its ready for install

The uploaded drawing shows my proposed track layout with isolator locations track feed locations and block identification

I plan on wiring the elecrofrog thru the tortoise as per many online recommendations I have read  

The purchase of the other DCC controls I have not fully decided on, I am planning on building a fascia control panel for switch control as well as control from a handheld throttle. In the future I would like to experiment with PC control using JMRI software (but one step at a time).

I'm welcoming anyone to look at my plan and see if I may have over looked something thus far before a start making things permanent. 

There is a reversing section across the middle that I had concerns about wiring a reversing module

 

Thanks

Chuck Stiles

NJ

 

Re: DCC Track Design for review

Flash Gordon
 

I have the NEO version of yahoo and I cannot find it in the files section.

I hate Neo.

Ed S

At 10:52 PM 1/22/2014, you wrote:


Railandsail, go to the WiringForDCC Yahoo group; on the left side, click on FILES.

The first half of that section is folders and the second half is individual files.

Scroll down until you come to "Layout for Review".



Paul O