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Can a 4awg cable be too short?

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messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Wed Nov 25, 2009 9:13 pm Post subject: Can a 4awg cable be too short?

Depending on the answer to this question, I might have been better off asking it earlier. I have 4awg welding cable between my battery contactor and my starter contactor. It's only 2" long, plus the ~1/2" crimped in each terminal. It fits fine, but now that the lugs are crimped on, it's fairly stiff. In a shorter wire or a longer section of this fat cable, I'd make them a little long. With this 2" jobbie, there's no give. I could position the contactors so it puts a little compression on the cable, or is this even necessary?

_________________
Dan

harley(at)AgelessWings.co
Guest

Posted: Thu Nov 26, 2009 5:20 am Post subject: Can a 4awg cable be too short?

Morning, Dan...

 

 First...hope you and everyone reading this has a great Thanksgiving!  

 

 As far as your short 4 gauge wire, I'm not sure what your concern is...tension on the contactor terminals maybe?  Or not being able to quite fit it between the two contactors?  In either case,  my first thought is to make a new "cable" that is long enough to form a loop so that it leaves one contactor's terminal and then loops around 360 degrees before it connects to the other.  If you can make this loop big enough, it should remove all tension from the terminals and allow some give and adjustment in the wire. 

 

 Harley 

  messydeer wrote: [quote]    	  Quote: 	
		  --> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com> (messydeer(at)yahoo.com)



Depending on the answer to this question, I might have been better off asking it earlier. I have 4awg welding cable between my battery contactor and my starter contactor. It's only 2" long, plus the ~1/2" crimped in each terminal. It fits fine, but now that the lugs are crimped on, it's fairly stiff. In a shorter wire or a longer section of this fat cable, I'd make them a little long. With this 2" jobbie, there's no give. I could position the contactors so it puts a little compression on the cable, or is this even necessary?



--------

Dan



  	
 [b]

klehman(at)albedo.net
Guest

Posted: Thu Nov 26, 2009 6:30 am Post subject: Can a 4awg cable be too short?

Often a copper or brass bar or strap works well if there will be a bend 

in it. I use a U shaped thin bar about 1/16" x 3/4" to connect two side 

by side contactors. No crimped connectors, it takes up less space, and 

it flexes amply so as to not stress terminals.

Ken

Harley wrote:

 	  Quote: 	
		   Morning, Dan...

 First...hope you and everyone reading this has a great Thanksgiving! 

 As far as your short 4 gauge wire, I'm not sure what your concern 

 is...tension on the contactor terminals maybe?  Or not being able to 

 quite fit it between the two contactors?  In either case,  my first 

 thought is to make a new "cable" that is long enough to form a loop so 

 that it leaves one contactor's terminal and then loops around 360 

 degrees before it connects to the other.  If you can make this loop big 

 enough, it should remove all tension from the terminals and allow some 

 give and adjustment in the wire.

 Harley

 ------------------------------------------------------------------------

 messydeer wrote:

> 

>

> Depending on the answer to this question, I might have been better off asking it earlier. I have 4awg welding cable between my battery contactor and my starter contactor. It's only 2" long, plus the ~1/2" crimped in each terminal. It fits fine, but now that the lugs are crimped on, it's fairly stiff. In a shorter wire or a longer section of this fat cable, I'd make them a little long. With this 2" jobbie, there's no give. I could position the contactors so it puts a little compression on the cable, or is this even necessary?

>

> --------

> Dan

>

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Thu Nov 26, 2009 8:21 am Post subject: Re: Can a 4awg cable be too short?

Thanks, guys 



It's the stress on the terminals I'm concerned about. I had outsourced the crimping, so going with the copper bar would be easier than doing the terminals again. I had read in the archives that Bob had a comic book describing bridging a short distance between 2 contactors, but couldn't find anything else on it. Maybe this is what was meant.

_________________
Dan

BobsV35B(at)aol.com
Guest

Posted: Thu Nov 26, 2009 8:37 am Post subject: Can a 4awg cable be too short?

Good Morning Harley,

  

 Or  --- Why not just use a Buss Bar?

  

 Beech has used them for years on the Bonanza line.

  

 Happy Skies,

  

 Old Bob

 AKA

 Bob Siegfried

 Downers Grove, Illinois

 Stearman N3977A

  

  In a message dated 11/26/2009 7:21:35 A.M. Central Standard Time,  harley(at)AgelessWings.com writes:

  	  Quote: 	
		  Morning,    Dan...



First...hope you and everyone reading this has a great    Thanksgiving!  



As far as your short 4 gauge wire, I'm not sure    what your concern is...tension on the contactor terminals maybe?  Or not    being able to quite fit it between the two contactors?  In either    case,  my first thought is to make a new "cable" that is long enough to    form a loop so that it leaves one contactor's terminal and then loops around    360 degrees before it connects to the other.  If you can make this loop    big enough, it should remove all tension from the terminals and allow some    give and adjustment in the wire. 



Harley 

      messydeer wrote:     	  Quote: 	
		   	  Quote: 	
		  --> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com> (messydeer(at)yahoo.com)



Depending on the answer to this question, I might have been better off asking it earlier. I have 4awg welding cable between my battery contactor and my starter contactor. It's only 2" long, plus the ~1/2" crimped in each terminal. It fits fine, but now that the lugs are crimped on, it's fairly stiff. In a shorter wire or a longer section of this fat cable, I'd make them a little long. With this 2" jobbie, there's no give. I could position the contactors so it puts a little compression on the cable, or is this even necessary?



--------

Dan



  	




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  [quote][b]

harley(at)AgelessWings.co
Guest

Posted: Thu Nov 26, 2009 8:52 am Post subject: Can a 4awg cable be too short?

Morning, Bob...

 

 >>Or  --- Why not just use a Buss Bar?<<

 

 I thought of that, but it sounded to me like he was trying to find a way to use a cable for some reason...so I suggested the loop! 

 

 ..and I hope you are enjoying your Thanksgiving as much as I am mine! 

 

 Harley

 

 BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote: [quote]            Good Morning Harley,

    

   Or  --- Why not just use a Buss Bar?

    

   Beech has used them for years on the Bonanza line.

    

   Happy Skies,

    

   Old Bob

   AKA

   Bob Siegfried

   Downers Grove, Illinois

   Stearman N3977A

    

      In a message dated 11/26/2009 7:21:35 A.M. Central Standard Time, harley(at)AgelessWings.com (harley(at)AgelessWings.com) writes:

    	  Quote: 	
		  Morning, Dan...

     

 First...hope you and everyone reading this has a great Thanksgiving!  

     

 As far as your short 4 gauge wire, I'm not sure what your concern is...tension on the contactor terminals maybe?  Or not being able to quite fit it between the two contactors?  In either case,  my first thought is to make a new "cable" that is long enough to form a loop so that it leaves one contactor's terminal and then loops around 360 degrees before it connects to the other.  If you can make this loop big enough, it should remove all tension from the terminals and allow some give and adjustment in the wire. 

     

 Harley 

      messydeer wrote:      	  Quote: 	
		          	  Quote: 	
		  --> AeroElectric-List message posted by: "messydeer" <messydeer(at)yahoo.com>



Depending on the answer to this question, I might have been better off asking it earlier. I have 4awg welding cable between my battery contactor and my starter contactor. It's only 2" long, plus the ~1/2" crimped in each terminal. It fits fine, but now that the lugs are crimped on, it's fairly stiff. In a shorter wire or a longer section of this fat cable, I'd make them a little long. With this 2" jobbie, there's no give. I could position the contactors so it puts a little compression on the cable, or is this even necessary?



--------

Dan



 	
     	
     	
   

       	  Quote: 	
		  



	
 [b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Nov 26, 2009 9:32 am Post subject: Can a 4awg cable be too short?

At 10:21 AM 11/26/2009, you wrote:

 	  Quote: 	
		  



Thanks, guys 



It's the stress on the terminals I'm concerned about. I had 

outsourced the crimping, so going with the copper bar would be 

easier than doing the terminals again. I had read in the archives 

that Bob had a comic book describing bridging a short distance 

between 2 contactors, but couldn't find anything else on it. Maybe 

this is what was meant.


	




See:



http://aeroelectric.com/Pictures/Wiring_Technique/Contactor_Interconnect/

        Bob . . .



         ---------------------------------------

        ( It's MATRONICS FUND RAISER MONTH!    )

        ( Do your part to keep this marvelous  )

        ( tool sharp and available to all our  )

        ( brothers in the OBAM aviation        )

        ( community.                           )

         ---------------------------------------

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Thu Nov 26, 2009 10:14 am Post subject: Re: Can a 4awg cable be too short?

Yes, thanks everybody. Those pics help, Bob 



Looks like some are made of brass and some of copper. Would copper work better in my case, since it would flex a bit more than brass? Post to post would be ~4" with a 90 twist.



My pic shows the situation. The cable from the battery positive to battery contactor is also pretty short, but I can mount it with enough flex to make me happy. There'll be a little more flex when the 2nd hole is drilled after the contactor is rotated a few degrees counterclockwise.



I had not particularly wisely opened a couple holes for the starter contactor to 3/16, then ended up having my starter lead too short. That's what the 3/16 clecos go through. So I moved things over a couple inches and can use one of the bigger holes for the battery contactor. 



I had hoped the starter contactor  could use the other big hole, as shown in the pic, but there is a 3/4" square tube stiffener it would interfere with behind the vertical row of holes. Due to the starter cable length, I can only move the starter contactor to the right (referenced from the pic) and/or up. It only needs to go an inch or less to straddle the firewall stiffener, but the cable won't make it that far.

short contactor cable.jpg

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_________________
Dan

slipstream(at)wavecable.c
Guest

Posted: Thu Nov 26, 2009 10:20 am Post subject: Can a 4awg cable be too short?

Bus bar stock is Van's setup as well.  Van's plans actually call for it to be doubled-up between the contactors.  In such short distances, I think it's easier to work with than soldered terminal lugs in 4ga cable.

  

 Brooks

         [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Thu Nov 26, 2009 11:11 am Post subject: Can a 4awg cable be too short?

Good Afternoon Dan,

  

 I would use copper. 

  

 It has better conductivity and withstands bending better. If you look  closely at 'Lectric Bob's Beechcraft photos you may note that Beech often  applies a coating over their buss bars, I have used tool handle dip  material for such purposes

  

 Happy Skies,

  

 Old Bob

 AKA

 Bob Siegfried

 Downers Grove, Illinois

 Stearman N3977A

  

  In a message dated 11/26/2009 12:17:25 P.M. Central Standard Time,  messydeer(at)yahoo.com writes:

  	  Quote: 	
		  http://forums.matronics.com//files/short_contactor_cable_400.jpg

	


  [quote][b]

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Thu Nov 26, 2009 11:54 am Post subject: Re: Can a 4awg cable be too short?

 	  Quote: 	
		  I would use copper. 



It has better conductivity and withstands bending better. If you look closely at 'Lectric Bob's Beechcraft photos you may note that Beech often applies a coating over their buss bars, I have used tool handle dip material for such purposes 	




Thanks, Bob 



I did notice that pic and could see a little copper colored area just around one connection, but didn't know what to use for the insulation. If my hardware store doesn't have 063 I can get some from Vans, like Brooks said. But Brooks, you said Vans says to double it? Not having it in hand, I'd be concerned about it being too stiff then. According to my notes, #4 cross section is 0.0327 sq in. So 063 x 1/2" would purtneer the same without doubling.

_________________
Dan

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Nov 26, 2009 10:42 pm Post subject: Can a 4awg cable be too short?

At 01:54 PM 11/26/2009, you wrote:

 	  Quote: 	
		  

 > I would use copper.

 >

 > It has better conductivity and withstands bending better. If you 

 look closely at 'Lectric Bob's Beechcraft photos you may note that 

 Beech often applies a coating over their buss bars, I have used 

 tool handle dip material for such purposes

Thanks, Bob 



I did notice that pic and could see a little copper colored area 

just around one connection, but didn't know what to use for the 

insulation. If my hardware store doesn't have 063 I can get some 

from Vans, like Brooks said. But Brooks, you said Vans says to 

double it? Not having it in hand, I'd be concerned about it being 

too stiff then. According to my notes, #4 cross section is 0.0327 sq 

in. So 063 x 1/2" would purtneer the same without doubling.


	


    You're going to drill 5/16" holes in the straps

    so 5/8" width material would give you better edge

    margins. But given the necessary twist and the

    angles . . . I'd go for a longer piece of 4AWG

    installed for comfortable as opposed to tight

    fit. It's going to be a whole bunch easier to

    fabricate and will look nicer in the long run.

    An extra inch or more in wire length is not

    going to be a performance issue.



    Bob . . .

 	  Quote: 	
		  --------

Dan





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p 74969#274969




	




        Bob . . .



         ---------------------------------------

        ( It's MATRONICS FUND RAISER MONTH!    )

        ( Do your part to keep this marvelous  )

        ( tool sharp and available to all our  )

        ( brothers in the OBAM aviation        )

        ( community.                           )

         ---------------------------------------

jay(at)horriblehyde.com
Guest

Posted: Thu Nov 26, 2009 11:07 pm Post subject: Can a 4awg cable be too short?

I find that a good source of copper is copper water pipe; heat it up to

almost red hot with a  blow torch and let it cool naturally to anneal it and

then you can hammer or squash it flat in a vice and cut it to size.  A

couple of layers of heat shrink for insulation and you've got the bus bar/

connector.



SA Jay

--

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Fri Nov 27, 2009 5:14 am Post subject: Re: Can a 4awg cable be too short?

One picture is worth a thousand words. Fatwire is to be connected in roughly the same way as hydraulic hose.



Think electricity instead of fluid and See: http://www.hydraulicspneumatics.com/200/FPE/Conductors/Article/True/6418/Conductors

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Fri Nov 27, 2009 11:07 pm Post subject: Re: Can a 4awg cable be too short?

Thanks, guys 



I ended up going with the cable. Cut the longer piece and took it to the hardware store where they crimped it for nothing. For good measure, I soldered the ends when I got it home. Fits nice with a good arc to it.

_________________
Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Sat Nov 28, 2009 11:15 am Post subject: Re: Can a 4awg cable be too short?

Here are some pics of the new cable. The hand crimping tool they used had was like a bolt cutter, with long handles. The indentation left was roughly a 3/16" cube.

4awg soldered.jpg

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HWS crimped #4.jpg

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Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Sat Nov 28, 2009 11:23 am Post subject: Re: Can a 4awg cable be too short?

last pic

new short 4awg in place.jpg

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Dan

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