tips needed to chase dc short - 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 Tree1Likes
Reply
 
LinkBack Thread Tools
  #11  
Old 06-26-2013
ebs001's Avatar
Senior Member
 
Join Date: May 2006
Location: Ottawa, Canada
Posts: 2,170
Thanks: 5
Thanked 21 Times in 19 Posts
Rep Power: 9
ebs001 is on a distinguished road
Re: tips needed to chase dc short

Quote:
Originally Posted by chucklesR View Post
I'm not buying the 'slow load' causing a short eventually.

I'd call this an intermittent short, very hard to find because you can test and test and if it's not shorting at the moment you won't find it. Electricians that charge by the hour love these kinds of shorts.

You're going to have to trace every wire and wiggle it while you do. Hopefully since you say it's the 'port side breaker' you are talking a couple of loads - not dozens.
You make (honestly) be better off just replacing the wiring of one load at a time, that depends on the age of the boat, your budget and your time.

On the other hand, you could just transfer one load at at time to the starboard breaker. When it trips off you know you've found the faulty load - replace every inch of that circuit and you may be done.
It's not intermittent, though. The breaker trips every time and within 30 seconds of turning on the breaker and his ammeter always shows current with all loads off.
Reply With Quote Quick reply to this message Share with Facebook
  #12  
Old 06-26-2013
fryewe's Avatar
Senior Member
 
Join Date: Dec 2004
Location: Gulf Coast.
Posts: 1,175
Thanks: 24
Thanked 45 Times in 45 Posts
Rep Power: 10
fryewe is on a distinguished road
Re: tips needed to chase dc short

Not familiar with your circuitry but it may be simpler to find...

-if the port DC breaker supplies a bus that loads are powered individually from you can lift ALL the leads from the bus and check the current through the breaker (mark the leads before removing them from the bus unless they have wire markers or unless color coded and then draw a simple diagram of the bus for use in reattaching)...

-and then replace them one at a time until the culprit is found.

Even if a a couple of systems that are powered off that breaker aren't on the bus it may still be useful to do this...

-if after lifting the leads from the bus the breaker still trips it is likely one of the directly powered loads. They should be individually fused so you can pull fuses to further isolate.
Reply With Quote Quick reply to this message Share with Facebook
  #13  
Old 06-26-2013
lajimo's Avatar
Senior Member
 
Join Date: Sep 2011
Posts: 187
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 4
lajimo is on a distinguished road
tips needed to chase dc short

Lots of great ideas here - I'm working through them and will spend some quality time chasing it this weekend. Some clarification : In my panel the tripping breaker is connected to a bus bar with a total of six other breakers. None of the others have any issues. The breaker in question powers the starboard (don't know why I said port before) side cabin lights and two small fans. The lights and fans work when the breaker is first turned on and then it flips off. Even with all lights and fans switched off, the breaker will still flip. On the panel there is a cumulative analog ammeter that shows the total load across all breakers. This appears to be working properly as I can watch the load build as I turn circuits on, and the bigger items like the icebox show a bigger load etc. for regular usage it stays between 5 and 10 amps. However, as soon as I turn on the starboard breaker switch the meter goes above 20 and stays there until the breaker flips off.
Reply With Quote Quick reply to this message Share with Facebook
  #14  
Old 06-27-2013
ebs001's Avatar
Senior Member
 
Join Date: May 2006
Location: Ottawa, Canada
Posts: 2,170
Thanks: 5
Thanked 21 Times in 19 Posts
Rep Power: 9
ebs001 is on a distinguished road
Re: tips needed to chase dc short

Quote:
Originally Posted by lajimo View Post
Lots of great ideas here - I'm working through them and will spend some quality time chasing it this weekend. Some clarification : In my panel the tripping breaker is connected to a bus bar with a total of six other breakers. None of the others have any issues. The breaker in question powers the starboard (don't know why I said port before) side cabin lights and two small fans. The lights and fans work when the breaker is first turned on and then it flips off. Even with all lights and fans switched off, the breaker will still flip. On the panel there is a cumulative analog ammeter that shows the total load across all breakers. This appears to be working properly as I can watch the load build as I turn circuits on, and the bigger items like the icebox show a bigger load etc. for regular usage it stays between 5 and 10 amps. However, as soon as I turn on the starboard breaker switch the meter goes above 20 and stays there until the breaker flips off.
Do what I suggested above and you will locate your problem. You can skip the pigtail suggestion if you wish and work through the circuit in the same way as I suggested and then reset the beaker each time until you get it to stay on. . I check with the fans first. From your description of the problem they appear to be the more likely suspects.
Reply With Quote Quick reply to this message Share with Facebook
  #15  
Old 06-27-2013
travlineasy's Avatar
Morgan 33 O.I. Perryville
 
Join Date: Dec 2010
Location: Maryland
Posts: 2,512
Thanks: 3
Thanked 72 Times in 62 Posts
Rep Power: 4
travlineasy will become famous soon enough
Re: tips needed to chase dc short

Sounds like an easy fix to me. Just turn everything off that's connected to that particular breaker circuit. Then, disconnect the positive wire going to the breaker, place an ammeter in the line. Now, turn the breaker on. If you get any current reading at all, begin disconnecting the wires from the individual items, fan, light, etc..., until there is no reading. When you get to where there is NO current flowing, you've narrowed down the culprit. I suspect it one of the fans - they tend to do some nasty things if they've been onboard for more than a decade.

Good Luck,

Gary
Reply With Quote Quick reply to this message Share with Facebook
  #16  
Old 06-28-2013
ebs001's Avatar
Senior Member
 
Join Date: May 2006
Location: Ottawa, Canada
Posts: 2,170
Thanks: 5
Thanked 21 Times in 19 Posts
Rep Power: 9
ebs001 is on a distinguished road
Re: tips needed to chase dc short

Quote:
Originally Posted by travlineasy View Post
Sounds like an easy fix to me. Just turn everything off that's connected to that particular breaker circuit. Then, disconnect the positive wire going to the breaker, place an ammeter in the line. Now, turn the breaker on. If you get any current reading at all, begin disconnecting the wires from the individual items, fan, light, etc..., until there is no reading. When you get to where there is NO current flowing, you've narrowed down the culprit. I suspect it one of the fans - they tend to do some nasty things if they've been onboard for more than a decade.

Good Luck,

Gary
This is basically what I suggested but using a 12v pigtail light in line instead of a ammeter. The problem with an ammeter in this particular instance is that it has very low resistance and the breaker will trip within 30 seconds of turning it on. I also like the light because it's a quick an easy visual reference. Usually on a boat you can see the light at all times.
Reply With Quote Quick reply to this message Share with Facebook
  #17  
Old 06-29-2013
lajimo's Avatar
Senior Member
 
Join Date: Sep 2011
Posts: 187
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 4
lajimo is on a distinguished road
tips needed to chase dc short

Got it! Ceiling light in forward head. (Just used for storage right now, don't go in there much. )
Reply With Quote Quick reply to this message Share with Facebook
  #18  
Old 06-29-2013
fryewe's Avatar
Senior Member
 
Join Date: Dec 2004
Location: Gulf Coast.
Posts: 1,175
Thanks: 24
Thanked 45 Times in 45 Posts
Rep Power: 10
fryewe is on a distinguished road
Re: tips needed to chase dc short

Congratulations!!! What method of isolating it did you use?
__________________
“Sailors, with their built in sense of order, service and discipline, should really be running the world.” – Nicholas Monsarrat
Reply With Quote Quick reply to this message Share with Facebook
  #19  
Old 06-29-2013
jimgo's Avatar
Asleep at the wheel
 
Join Date: Sep 2011
Location: Pennsylvania
Posts: 3,012
Thanks: 71
Thanked 116 Times in 114 Posts
Rep Power: 4
jimgo is on a distinguished road
Re: tips needed to chase dc short

Was it the bulb or the light itself?
__________________
- Jim
Home: Western Philly 'burbs
1980 Allmand 31
1975 Albacore 15


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
  #20  
Old 07-02-2013
lajimo's Avatar
Senior Member
 
Join Date: Sep 2011
Posts: 187
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 4
lajimo is on a distinguished road
tips needed to chase dc short

i used analog ammeter which is already in the panel and just kept disconnecting loads until i found it. It is the light itself - original to boat 1985 - and corroded. Of course I started aft and worked forward, so it took awhile. .
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
Sanity check needed on short-term house bank configuration rhumbunctious Gear & Maintenance 13 12-02-2010 08:14 PM
Tips needed as a Young Woman Sailing! ElementQuest herSailNet 26 11-23-2009 09:49 PM
Info, experience, tips needed sailing from Turks and Caicos to Florida keys pireality General Discussion (sailing related) 4 07-21-2009 12:01 PM
crew needed (short notice) san fran-seattle end of Sept. lmonson Crew Wanted/Available 1 09-22-2006 02:49 AM


All times are GMT -4. The time now is 07:03 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.