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Powering "minor" devices

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trigo(at)mail.telepac.pt
Guest

Posted: Tue Apr 26, 2016 2:43 am Post subject: Powering "minor" devices

Bob and all



I have to get power to 5 or 6 critters who will live in my instrument panel (instruments' lights, LED strip, USB socket, warning lights, etc.).

I don't want to have a dedicated circuit breaker (or fuse - please don't start a CB versus Fuse war again...), so I decided to use a small buss, powered from a single CB, and then connect all those devices to this small buss.



Questions:

  - is this the right and elegant solution to this particular need?

 - which kind of buss should I use, a single bolt/screw, or a small bar?

 - as for the circuit-breaker, should I use a 2A, which would be what each circuit would need, or should I "upgrade" it to, say 5A, to protect all wires for the case all of them are simultaneously transporting energy?



Regards

Carlos



Enviado do meu iPhone

ARGOLDMAN(at)aol.com
Guest

Posted: Tue Apr 26, 2016 3:44 am Post subject: Powering "minor" devices

Carlos, consider individual poly fuses for those. a short in one of the  "minors" will not effect the others and you have protection. 

  

 Practice Safe sparks.

  

 Rich

  

  In a message dated 4/26/2016 3:44:28 A.M. Pacific Daylight Time,  trigo(at)mail.telepac.pt writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: Carlos Trigo    <trigo(at)mail.telepac.pt>



Bob and all



I have to get power to    5 or 6 critters who will live in my instrument panel (instruments' lights, LED    strip, USB socket, warning lights, etc.).

I don't want to have a dedicated    circuit breaker (or fuse - please don't start a CB versus Fuse war again..),    so I decided to use a small buss, powered from a single CB, and then connect    all those devices to this small buss.



Questions:

  - is this    the right and elegant solution to this particular need?

- which kind of    buss should I use, a single bolt/screw, or a small bar?

- as for the    circuit-breaker, should I use a 2A, which would be what each circuit would    need, or should I "upgrade" it to, say 5A, to protect all wires for the case    all of them are simultaneously transporting    energy?



Regards

Carlos



Enviado do meu  ========================  = Use   utilities  Day  ================================================               - MATRONICS WEB FORUMS  ================================================              - NEW MATRONICS LIST WIKI -_-=                - List Contribution Web Site  sp;                             ===================================================

yellowduckduo(at)gmail.co
Guest

Posted: Tue Apr 26, 2016 4:40 am Post subject: Powering "minor" devices

I would use a single bolt and 5 amp protection with awg22 wire.

I would also daisy chain anywhere that made sense. ie if not convenient 

to bring some wires back to the CB then split them off from any of the 

downstream connections.

Don't drop down to smaller wires though as the 5 amp CB might not 

properly protect some smaller wires.

Ken



On 26/04/2016 6:41 AM, Carlos Trigo wrote:

 	  Quote: 	
		   



 Bob and all



 I have to get power to 5 or 6 critters who will live in my instrument panel (instruments' lights, LED strip, USB socket, warning lights, etc.).

 I don't want to have a dedicated circuit breaker (or fuse - please don't start a CB versus Fuse war again...), so I decided to use a small buss, powered from a single CB, and then connect all those devices to this small buss.



 Questions:

    - is this the right and elegant solution to this particular need?

   - which kind of buss should I use, a single bolt/screw, or a small bar?

   - as for the circuit-breaker, should I use a 2A, which would be what each circuit would need, or should I "upgrade" it to, say 5A, to protect all wires for the case all of them are simultaneously transporting energy?



 Regards

 Carlos



 Enviado do meu iPhone

stein(at)steinair.com
Guest

Posted: Tue Apr 26, 2016 6:30 am Post subject: Powering "minor" devices

Not debating your rationale, but I will still give you my 2 cents and that

is not to do what you're doing....because I'm wondering what/how you're

going to size your protection device at? Will it be sized for the 2-4A USB

charger, or the .2A LED strip, or the warning lights, or the combination of

all of them (in which case the device would potentially be too large to

protect the wiring to any single one of them)?  At this point in your build,

don't step over a dollar to pick up a dime.



One of the easiest solutions to that conundrum is a small fuse block with a

single input that has 6+ circuits that you can individually fuse. You could

still hide it behind a screen where it has easy access, but it'd be much

simpler and much more elegant in my opinion....plus the quickest and easiest

to wire up yet still allowing you the option for multiple protected circuits

quite easy and cleanly. 



If you're still dead set against protecting each device/circuit (which I

stress would be the proper method), I'd say use either a smaller terminal

strip with jumpers or a remade buss bar with either bolts or screws on it.

Again, the goal here is to keep it simple, clean and have the least amount

of "failure points" in the system.



Cheers,

Stein

--

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Apr 26, 2016 7:26 am Post subject: Powering "minor" devices

At 05:41 AM 4/26/2016, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: Carlos Trigo <trigo(at)mail.telepac.pt>



 Bob and all



 I have to get power to 5 or 6 critters who will live in my instrument panel (instruments' lights, LED strip, USB socket, warning lights, etc.).

 I don't want to have a dedicated circuit breaker (or fuse - please don't start a CB versus Fuse war again...), so I decided to use a small buss, powered from a single CB, and then connect all those devices to this small buss. 	


  It's entirely rational. It's done on a larger scale

  in TC aircraft.



  Consider the distribution tree and its branches.

  A similar thing is in operation all over your

  house. Any one appliance, like a hair dryer,

  may have a current/overheat protector built

  in. The breaker feeding the outlet comes from

  a bus in your breaker box. A transformer behind

  your house probably has a protective device on

  the hv primary feeder . . . and so it goes up

  the line until you get to a steam driven turbine

  somewhere that powers a whole lot of hair dryers.



  The goal in designing distribution is to protect

  branches with devices robust enough to not be

  nuisance tripped by anticipated load and fault

  conditions downstream. For example, the main

  breaker for your house should not operate when

  every branch is loaded to capacity and only

  one branch is faulted causing its particular

  breaker to open. Hence, a short in nobody's

  hair dryer should turn out the lights in the

  the room, much less the whole neighborhood.



  A Hawker or King Air has multiple busses

  with feeders from heavier upstream sources.

  In every instance, a bus feeder is selected

  to be free of nuisance tripping due to 

  smaller faults downstream. There have been

  a number of suggestions for selection of

  protective devices . . . the choices are

  several and combinations are many. But one

  simple design rule applies: Don't let any

  single fault event propagate into other

  systems. Hence, you can use a fuse, cb,

  current limiter or automatic solid-state

  wire-protection gee-whizz at the source

  end of any feeder . . . just make sure it

  is sized for DYNAMIC performance to grunt

  the load of any single downstream fault.



  Breakers are very slow compared to fuses.

  A breaker protected 'buss feeder' to a

  fuse block is a perfectly rational thing

  to consider. You may want to size the bus

  feeder and wire not so much for temperature

  effects of maximum anticipated loads . . .

  but from the perspective of staying put

  when your GPS feeder fuse is called upon

  to operate. A 30A breaker driving a 10AWG

  feeder to a block of ten, 1A fuses may

  be a bit overkill . . . but it does

  not violate the first rule of feeder

  protection - protect the feeder but ignore

  downstream faults.



 

 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Apr 26, 2016 7:28 am Post subject: Powering "minor" devices

 	  Quote: 	
		  



 If you're still dead set against protecting each device/circuit (which I

 stress would be the proper method), 	


   RIGHT ON!



 

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Apr 26, 2016 9:01 am Post subject: Re: Powering

How minor are those items?  Do you care if they all stop working at once?  If they all go dead, will it be a non event that can wait until landing?  If not, follow Stein's advice.  Install a 4 or 6 position fuse block.  It does not necessarily have to be in-flight accessible.  The fuse block can be mounted out of sight.  You are better off waiting until safely on the ground before replacing a fuse.  I think that each and every electrical load should have its own fuse.  If one blows, you will know exactly which load is the problem.  Fuses are cheap.

  Years ago an airliner crashed because the pilot and copilot were distracted trying to replace an indicator lamp.

_________________
Joe Gores

trigo(at)mail.telepac.pt
Guest

Posted: Tue Apr 26, 2016 9:10 am Post subject: Powering "minor" devices

Bob

Thanks for your answer, but to be frank you got a little bit too much philosophical, so in the end I think I did not quite got your message

Could you please be a little more specific on answering my 3 questions?

Thanks

Carlos



Enviado do meu iPhone



No dia 26/04/2016, Ã s 16:25, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> escreveu:

 	  Quote: 	
		    At 05:41 AM 4/26/2016, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)>



 Bob and all



 I have to get power to 5 or 6 critters who will live in my instrument panel (instruments' lights, LED strip, USB socket, warning lights, etc.).

 I don't want to have a dedicated circuit breaker (or fuse - please don't start a CB versus Fuse war again...), so I decided to use a small buss, powered from a single CB, and then connect all those devices to this small buss. 	


  It's entirely rational. It's done on a larger scale

  in TC aircraft.



  Consider the distribution tree and its branches.

  A similar thing is in operation all over your

  house. Any one appliance, like a hair dryer,

  may have a current/overheat protector built

  in. The breaker feeding the outlet comes from

  a bus in your breaker box. A transformer behind

  your house probably has a protective device on

  the hv primary feeder . . . and so it goes up

  the line until you get to a steam driven turbine

  somewhere that powers a whole lot of hair dryers.



  The goal in designing distribution is to protect

  branches with devices robust enough to not be

  nuisance tripped by anticipated load and fault

  conditions downstream. For example, the main

  breaker for your house should not operate when

  every branch is loaded to capacity and only

  one branch is faulted causing its particular

  breaker to open. Hence, a short in nobody's

  hair dryer should turn out the lights in the

  the room, much less the whole neighborhood.



  A Hawker or King Air has multiple busses

  with feeders from heavier upstream sources.

  In every instance, a bus feeder is selected

  to be free of nuisance tripping due to 

  smaller faults downstream. There have been

  a number of suggestions for selection of

  protective devices . . . the choices are

  several and combinations are many. But one

  simple design rule applies: Don't let any

  single fault event propagate into other

  systems. Hence, you can use a fuse, cb,

  current limiter or automatic solid-state

  wire-protection gee-whizz at the source

  end of any feeder . . . just make sure it

  is sized for DYNAMIC performance to grunt

  the load of any single downstream fault.



  Breakers are very slow compared to fuses.

  A breaker protected 'buss feeder' to a

  fuse block is a perfectly rational thing

  to consider. You may want to size the bus

  feeder and wire not so much for temperature

  effects of maximum anticipated loads . . .

  but from the perspective of staying put

  when your GPS feeder fuse is called upon

  to operate. A 30A breaker driving a 10AWG

  feeder to a block of ten, 1A fuses may

  be a bit overkill . . . but it does

  not violate the first rule of feeder

  protection - protect the feeder but ignore

  downstream faults.



 

 

   Bob . . .

trigo(at)mail.telepac.pt
Guest

Posted: Tue Apr 26, 2016 9:41 am Post subject: Powering "minor" devices

Thank you Stein



I will consider your solution.



CT



Enviado do meu iPhone



No dia 26/04/2016, Ã s 15:28, Stein Bruch <stein(at)steinair.com> escreveu:



[quote] 

 

 Not debating your rationale, but I will still give you my 2 cents and that

 is not to do what you're doing....because I'm wondering what/how you're

 going to size your protection device at? Will it be sized for the 2-4A USB

 charger, or the .2A LED strip, or the warning lights, or the combination of

 all of them (in which case the device would potentially be too large to

 protect the wiring to any single one of them)?  At this point in your build,

 don't step over a dollar to pick up a dime.

 

 One of the easiest solutions to that conundrum is a small fuse block with a

 single input that has 6+ circuits that you can individually fuse. You could

 still hide it behind a screen where it has easy access, but it'd be much

 simpler and much more elegant in my opinion....plus the quickest and easiest

 to wire up yet still allowing you the option for multiple protected circuits

 quite easy and cleanly. 

 

 If you're still dead set against protecting each device/circuit (which I

 stress would be the proper method), I'd say use either a smaller terminal

 strip with jumpers or a remade buss bar with either bolts or screws on it.

 Again, the goal here is to keep it simple, clean and have the least amount

 of "failure points" in the system.

 

 Cheers,

 Stein

 

 

 --

trigo(at)mail.telepac.pt
Guest

Posted: Tue Apr 26, 2016 9:42 am Post subject: Powering "minor" devices

Thank you Ken

You did answer all my questions.

Carlos 

Enviado do meu iPhone

No dia 26/04/2016, Ã s 13:38, C&K <yellowduckduo(at)gmail.com> escreveu:

 	  Quote: 	

 I would use a single bolt and 5 amp protection with awg22 wire.

 I would also daisy chain anywhere that made sense. ie if not convenient to bring some wires back to the CB then split them off from any of the downstream connections.

 Don't drop down to smaller wires though as the 5 amp CB might not properly protect some smaller wires.

 Ken

> On 26/04/2016 6:41 AM, Carlos Trigo wrote:

> 

> 

> Bob and all

> 

> I have to get power to 5 or 6 critters who will live in my instrument panel (instruments' lights, LED strip, USB socket, warning lights, etc.).

> I don't want to have a dedicated circuit breaker (or fuse - please don't start a CB versus Fuse war again...), so I decided to use a small buss, powered from a single CB, and then connect all those devices to this small buss.

> 

> Questions:

>   - is this the right and elegant solution to this particular need?

>  - which kind of buss should I use, a single bolt/screw, or a small bar?

>  - as for the circuit-breaker, should I use a 2A, which would be what each circuit would need, or should I "upgrade" it to, say 5A, to protect all wires for the case all of them are simultaneously transporting energy?

> 

> Regards

> Carlos

> 

> Enviado do meu iPhone

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Apr 26, 2016 1:59 pm Post subject: Powering "minor" devices

At 12:09 PM 4/26/2016, you wrote:

  	  Quote: 	
		  Bob



 Thanks for your answer, but to be frank you got a little bit too much philosophical, so in the end I think I did not quite got your message

 Could you please be a little more specific on answering my 3 questions? 	


   If it were my airplane:



   Select a fuse-block (which becomes your minor-items bus)

   with sufficient number of slots to power planned devices

   plus a few spares . . . perhaps a 10-slot block.



   Wire this 'fuse bus' to your main bus through a

   robust feeder, say 14AWG.



   Put a 15A breaker or 20A fuse at the main bus

   end of this feeder.



   Populate the minor items bus with fuses no

   greater than say 3A so each item enjoys

   its own, protected source. 



 

 

   Bob . . .

stein(at)steinair.com
Guest

Posted: Tue Apr 26, 2016 2:40 pm Post subject: Powering "minor" devices

My exact recommendation as well!  Cheap, easy, light and accomplishes exactly what you want/need whilst still be serviceable and proper.

 

Cheers,

Stein

 

Do not archive.

 

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

Sent: Tuesday, April 26, 2016 4:58 PM

To: aeroelectric-list(at)matronics.com

Subject: Re: Powering "minor" devices

 

At 12:09 PM 4/26/2016, you wrote:



 	  Quote: 	
		  

Bob



Thanks for your answer, but to be frank you got a little bit too much philosophical, so in the end I think I did not quite got your message

Could you please be a little more specific on answering my 3 questions? 	




  If it were my airplane:



  Select a fuse-block (which becomes your minor-items bus)

  with sufficient number of slots to power planned devices

  plus a few spares . . . perhaps a 10-slot block.



  Wire this 'fuse bus' to your main bus through a

  robust feeder, say 14AWG.



  Put a 15A breaker or 20A fuse at the main bus

  end of this feeder.



  Populate the minor items bus with fuses no

  greater than say 3A so each item enjoys

  its own, protected source. 





  Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Apr 26, 2016 3:42 pm Post subject: Re: Powering

When trying to decide which is the best way to accomplish a task, I ask myself what is best in the long run, not what is the easiest or least expensive at the moment.  In this particular case, Stein and Bob have suggested the right and elegant long term solution.  A few years from now when one of those fuses blow, you will be thankful that 5 other electrical loads still work.  And you will know which device caused the fuse to blow.

_________________
Joe Gores

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