Connect two different sized wire together? - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance > Electrical Systems
 Not a Member? 


Like Tree2Likes
Reply
 
LinkBack Thread Tools
  #11  
Old 01-27-2012
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,435
Thanks: 12
Thanked 131 Times in 99 Posts
Rep Power: 15
Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
Quote:
Originally Posted by bljones View Post
I am surprised we haven't heard from Mainesail on this.
This is simple all you need is a 12-10 GA TO 8 GA step down butt splice. They are red color coded with a yellow stripe on the 12-10GA end.. They can be ordered on-line but you'll need a crimper that can do 8GA, which is rather rare. Pro's Kit makes a nice crimper with detachable crimp dies you can buy and they make a head for heat shrink crimps that has 8GA...

PLEASE do not solder or twist the wires together or use wire nuts. These wires are connected directly to a bank that likely has well over 3000 short circuit amps....!!! ALWAYS fuse this wire as close to the + battery post as possible...

12-10GA to 8GA Step Down Butt - Heat Shrink
kd3pc likes this.
__________________
______
-Maine Sail / CS-36T


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




© Images In Posts Property of Compass Marine Inc.



Last edited by Maine Sail; 01-27-2012 at 05:15 PM.
Reply With Quote Quick reply to this message Share with Facebook
  #12  
Old 01-27-2012
Member
 
Join Date: Apr 2011
Posts: 34
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
JRA1968 is on a distinguished road
@ MS. Why would you not solder a joint like the one described. A solder joint is surely better for current then a potentialy loose crimp and for and outside connection . I do like it when people do it that way cause its good job security for me. Lol . Cheers and strong winds
Reply With Quote Quick reply to this message Share with Facebook
  #13  
Old 01-29-2012
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,811
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 10
btrayfors will become famous soon enough btrayfors will become famous soon enough
Clearly, MaineSail has the best solution, provided that:

1. the OP is willing to purchase a minimum of 10 step-down butt connectors; and
2. that he has the proper crimper for AWG8 heat shrink terminals. Very few people do, and you've got to be careful not to damage the heat shrink covering.


Quote:
Originally Posted by kd3pc View Post
chip
some of these ideas to snip the 8 down in size and to make a somewhat physical connection are dangerous if you hope to pass any amount of current across that marginal connection. It will become a high resistance (hot) short and will impede the current flow.

I agree it's important to make a very good connection, but I don't agree that it can't be done right.

How are you going to know that the strands you cut away on one end are still in use on the other end? You need an electrical connection that is made of a physically stout connection that is not loose, impaired or faulty by design.

This is a cute argument, but electrically inaccurate. All the strands in the bundle are pressed together under great pressure at the terminal connections. We're talking DC current here -- a maximum of 11-12 amps @ 15-16VDC -- current will flow thru the entire bundle, more or less equally. Hey....most electrical connections work like this...plugs, terminal strips, circuit breakers, etc. Only a few strands actually make physical contact with the connector, but the DC current permeates the entire bundle.
......
In the OP's case, there are other considerations, since he wants to run the wire thru a tube and, presumably, keep the splice as thin as is consistent with a good, strong connection.

The other option someone mentioned above will work, too (use larger butt connection, e.g., AWG8 and double the AWG10 wire on itself), but that would result in a larger connection and would also require a proper crimper.

I certainly agree that however it's done, DO NOT solder the cables or use wire nuts, or "twist them together".

Just for the heck of it, here are a couple of pix showing the result of the solution I originally posted (and I don't at all want to say this is better than MaineSail's solution):

Marine Antennas

Pics are at the bottom of the page...click on each pic twice for full resolution.

Bill
Reply With Quote Quick reply to this message Share with Facebook
  #14  
Old 01-30-2012
kd3pc's Avatar
Senior Member
 
Join Date: Oct 2006
Location: Callao, VA
Posts: 1,347
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 9
kd3pc is on a distinguished road
Bill

you might want to do some homework on your "facts" ....the ability of that wire (yes made of strands) to carry current is directly related to the surface area of the strands, and thereby the wire. There is a lot of science in how many strands are laid up, how they laid and in terminations so that the wire is truly 100% functional. By you removing and altering it's makeup, you have in fact reduced it's ability to carry current. Further the current travels in the "skin" of the strands, and if you remove those strands, again the capacity to carry current is diminished.

current flow in the wire is the same whether DC or AC, one only changes directions every 60 cycles, the other doesn't.

wire size DOES make a difference, and while you may say the size does not matter (see post #6)...altering the diameter (really circular mils) reduces the capacity and characteristics of the wire...in this case removing the strands of a #8, effectively reduces it to function as a #10 or #12, now with a flaw.

Having seen and repaired quite a few "poor connections" and having been an electrician for many years, and trained in both low voltage splicing as well as HV splicing I was offering the benefit of my experience.

Your solution is half baked at best, and dangerous if not well done. You and the OP are surely free to do the splice any way you want, but I guarantee that you will have problems down the line using your process or some of the "non-mechanical" solutions proposed here
Reply With Quote Quick reply to this message Share with Facebook
  #15  
Old 01-30-2012
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,811
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 10
btrayfors will become famous soon enough btrayfors will become famous soon enough
Well, Dave, we're just going to have to agree to disagree.

To keep it short:

1. in a DC circuit current (electrons) flow throughout the wire, not just on the surface. This is not a radio frequency circuit.

2. AC circuits do in fact differ in that the electrons don't really flow....they influence neighboring ones.

3. Removing a few strands from the end of an AWG8 wire, and crimping it properly in a butt connector, does not render it effectively an AWG10 wire throughout its length in terms of its DC current carrying ability.

4. The issue here is voltage drop anyway, not current-carrying ability per se. AWG8 is specified because of the longish run between the panels and the batteries.

I would challenge you -- or anyone else -- to measure a perceptible voltage or current difference at the battery end of the AWG8 wire carrying an 11-12A DC load between two different setups: one connected at the other end to an AWG10 wire using butt-reducers; or one using the method I've outlined above.

Any EE's wanna pitch in?

Bill

Last edited by btrayfors; 01-30-2012 at 09:01 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #16  
Old 01-30-2012
pdqaltair's Avatar
Senior Member
 
Join Date: Nov 2008
Location: Deale, MD
Posts: 2,252
Thanks: 1
Thanked 35 Times in 35 Posts
Rep Power: 6
pdqaltair is on a distinguished road
Quote:
Originally Posted by btrayfors View Post
1. in a DC circuit current (electrons) flow throughout the wire, not just on the surface. This is not a radio frequency circuit.

Bill
I do like to see credible refferences for bold statments.

a. wire manufactures show the same rating for stranded and solid wire of the same guage.
b. stranded wire is thicker for any given guage, to get thesame cross sectional area.

Higher frequencies are different, but this is DC. Even at 60hz the skin effec thickness doesn't matter for cables under 1/2-inch.
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies
Skin effect - Wikipedia, the free encyclopedia

For practical purposes, urban legend started by folks trying to sell monster audio cables.
__________________
(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")

"Well, I just climb up to them."

by Joe Brown, English rock climber




To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #17  
Old 01-30-2012
SanDiegoChip's Avatar
Senior Member
 
Join Date: Jun 2007
Location: Puerto Vallarta Mexico
Posts: 393
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
SanDiegoChip is on a distinguished road
Your right-not too different

Ok I did not realize the wires were so close to each other. I went to Marine Exchange and looked at the wire and saw (we ordered the wire over the web) size was not that different. We bought some connectors to use and we have the good heat shrink with the glue in it. We may need to get a few more connectors a size up for doubling up some wire. We have a hydraulic crimping too we got at Harbor Freight we can use for this job. We bought it for the anchor windlass connectors and thought it was a onetime use but we still have it. We actually gave it to a family member but borrowed it back
Any way we have been doing so much work with battery cables I just thought this wire was heavier like a 4 awg for some reason.
We will crimp the wires and not cut any strands down. May have to double over the #10 but will see. Let you know how it goes. The reason for the larger wires is for the longer run and we do not want to defeat that.


This pic shows the connectors we got so far. There is a on\off switch we need to wire also and through a 50 AMP fuse on the battery to 8 awg wire.
Reply With Quote Quick reply to this message Share with Facebook
  #18  
Old 01-30-2012
tap tap is offline
Senior Member
 
Join Date: Apr 2009
Posts: 176
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
tap is on a distinguished road
You might want to check the review for that hydraulic HF crimper. The one I saw wasn't designed for electrical connections. They were selling it for that, but the dies are actually for crimping steel cables and completely the wrong size for electrical connectors.
Reply With Quote Quick reply to this message Share with Facebook
  #19  
Old 01-30-2012
Maine Sail's Avatar
Senior Member
 
Join Date: Jan 2003
Location: Maine Coast
Posts: 5,435
Thanks: 12
Thanked 131 Times in 99 Posts
Rep Power: 15
Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice Maine Sail is just really nice
Pro's Kit Pro Crimp Frame

Heat Shrink Die Kit 22GA to 8GA

For $46.00 you can get a darn nice crimp tool and a die set for heat shrink crimps. You'll be able to use it for years... They also sell dies for just about any crimp you'll ever need to make.
__________________
______
-Maine Sail / CS-36T


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.




© Images In Posts Property of Compass Marine Inc.


Reply With Quote Quick reply to this message Share with Facebook
  #20  
Old 01-31-2012
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,724
Thanks: 2
Thanked 95 Times in 92 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about


Maine, since when does a plain oval shape die count as a proper crimp for anything?

Chip, is it at all feasible to simply remove the thinner wire from the airgen, and run the 8AWG cable all the way into it? That also eliminates the need to splice completely.

The HF tool may be the only one of its kind on the market and it sure LOOKS good, but if you find the thread discussing it...there's some question of exactly wtf they are selling and apparently even that varies from lot to lot.

Of course, folks have been known to simply use a vise and "swage" the hell out of battery lugs when there's no fancy $200 crimping tool around.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
About to put in wind generator where to connect green ground wire? Mariner777 Electrical Systems 3 06-25-2011 07:04 AM
Kid-sized gear. JaredC Cruising and Sailing with Children 11 02-16-2011 11:10 AM
Mid -sized sailboat wanted hrmacdonald2000 Boat Review and Purchase Forum 4 11-02-2004 01:08 PM
A Pocket-Sized Adventure Bruce Caldwell Learning to Sail Articles 0 02-16-2000 07:00 PM
A Pocket-Sized Adventure Bruce Caldwell Cruising Articles 0 02-16-2000 07:00 PM


All times are GMT -4. The time now is 12:22 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.