Need help with wiring boat. - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 16 Old 03-04-2016 Thread Starter
Senior Member
 
Join Date: Feb 2002
Location: Oceanside CA
Posts: 1,168
Thanks: 28
Thanked 25 Times in 25 Posts
Rep Power: 15
 
Need help with wiring boat.

My new to me Potter 19 came with a rat's nest for wiring. I am starting over to make it right. So far I have purchased a 5 way switch panel and cut out the area to make it fit. The boat had a fairly nice setup for a P19 that is with two batteries and a batt switch. Previously the boat had a 4 stroke outboard with alternator so there are big cables coming from that to the batt switch. All wires leading from the alternator, and both batteries to the batt switch are beaffy 4 or 6 gauge wires appropriate for a bigger boat. Leading away from the battery switch to the boat's DC switch panel was a 12 or 14 gauge wire. Nowhere along the way are any fuses.





My list of equipment onboard is:
  • 3 LED interior lights
  • LED Nav Lights
  • Masthead Steaming/Anchor 2 bulb LED combo.
  • 3- 12 V "cigarette lighter" plugs

Possible future additions:
  • Fixed VHF radio
  • Tiller Autopilot.

The DC panel is on the right side of the boat and the Battery Switch is on the Left, I figure a 10-12 foot run. I am heading to the boat today to remove the rat's nest and will know the distance later.

Would a 10 gauge wire work with a 30A inline fuse work? If not:

What size wire should I have leaving the battery switch to the DC panel to handle this load?

How do I add a Fuse to this line?

How do I step down from a big fat wire to the 12 or 14 gauge on my DC panel?

Jordan
West Wight Potter 14 "Lemon Drop"
Oceanside CA
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.
jephotog is online now  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 16 Old 03-04-2016
Senior Member
 
Join Date: Feb 2011
Location: San Francisco Bay area
Posts: 3,035
Thanks: 9
Thanked 76 Times in 76 Posts
Rep Power: 6
 
Re: Need help with wiring boat.

I can't say I'm very keen on those uninsulated P clips. I though they were for piping? Eventually they might cut through the insulation, then you'll have live P clips. Wait a minute, it gets better! There's a P clip on the plus and negative wires, both fixed to the same metal stud! So that's where the fire will start.

My preferred method is these :

https://hermanproav.com/product/4797...wqrRoChbLw_wcB

If you need to change something, just cut the cable tie, install another. The mount stays put. Cool.

Also it looks like there are two wires going into one crimp. Better to install a ring crimp on both wires, and have two ring terminals on the stud.

Bristol 31.1, San Francisco Bay

Last edited by MarkSF; 03-04-2016 at 02:35 PM.
MarkSF is online now  
Quote Quick Reply Share with Facebook
post #3 of 16 Old 03-04-2016 Thread Starter
Senior Member
 
Join Date: Feb 2002
Location: Oceanside CA
Posts: 1,168
Thanks: 28
Thanked 25 Times in 25 Posts
Rep Power: 15
 
Where to put it all.

The wiring and panel is right above where the porta-potti belongs on this boat. I could install the wire distribution right beneath the DC switch panel but do not want all the wires and distribution blocks exposed to the flammable gas in the area..

Actually I think it would just look cleaner and easier if I moved the two distribution blocks forward a bit. Just forward of this area is one of the batteries so the jumper to the negative bus would be kept short and cleaner. I would need to add 3-4 foot jumpers to bring the power from the switch panel to the terminal block.

Here are the two blocks I have for distributing Negative and Power from the DC switch panel.



Below are pictures of the two areas. Area 1 is just below the switch panel in the Porta-potti cabinet area 2 is forward of this, next to the battery. I have some star board i would build up a 1/2 panel and epoxy it to the hull just under the hull liner to mount the two distribution blocks. This would keep most of the wiring and the distribution out of sight and no chance of it being bumped. All feedback appreciated.

Location #1


Location #2

Jordan
West Wight Potter 14 "Lemon Drop"
Oceanside CA
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.
jephotog is online now  
Quote Quick Reply Share with Facebook
post #4 of 16 Old 03-04-2016 Thread Starter
Senior Member
 
Join Date: Feb 2002
Location: Oceanside CA
Posts: 1,168
Thanks: 28
Thanked 25 Times in 25 Posts
Rep Power: 15
 
Re: Need help with wiring boat.

Quote:
Originally Posted by MarkSF View Post
Thanks Mark,
I have a bunch of those type of Cable mounts left over from my previous boat. I like them for the same reasons. I plan on using thickened epoxy to mount them throughout the boat where wires will be running. Overall it will be a very simple layout, but I want to do it right.

Another red flag is the wire you are talking about makes a 180 bend at the ring. The positive and negative you see coming from the top are from the aft part of the boat coming from the boat alternator. There was a 4 outboard on there but it was stollen and the wires cut short before I purchased the boat. I am not sure the wires are still long enough to reach an outboard but I can either move these wires and coil them out of the way for a future alternator or Solar panel or remove it and use it to make the run from the battery switch to the DC switch panel.

Jordan
West Wight Potter 14 "Lemon Drop"
Oceanside CA
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.
jephotog is online now  
Quote Quick Reply Share with Facebook
post #5 of 16 Old 03-04-2016
Learning the HARD way...
 
eherlihy's Avatar
 
Join Date: Jan 2007
Location: Boston / Ft Myers Area
Posts: 5,073
Thanks: 258
Thanked 170 Times in 167 Posts
Rep Power: 10
 
Re: Need help with wiring boat.

Quote:
Originally Posted by jephotog View Post
... Leading away from the battery switch to the boat's DC switch panel was a 12 or 14 gauge wire. Nowhere along the way are any fuses.





My list of equipment onboard is:
  • 3 LED interior lights
  • LED Nav Lights
  • Masthead Steaming/Anchor 2 bulb LED combo.
  • 3- 12 V "cigarette lighter" plugs

Possible future additions:
  • Fixed VHF radio
  • Tiller Autopilot.

The DC panel is on the right side of the boat and the Battery Switch is on the Left, I figure a 10-12 foot run. I am heading to the boat today to remove the rat's nest and will know the distance later.

Would a 10 gauge wire work with a 30A inline fuse work? If not:

What size wire should I have leaving the battery switch to the DC panel to handle this load?

How do I add a Fuse to this line?

How do I step down from a big fat wire to the 12 or 14 gauge on my DC panel?
Do not use an inline 30A fuse.

Use an MRBF on the batteries. Use an appropriately sized wire to run from the batteries to the battery switch, and then from the common lead to the bus on the breaker panel.

Your projected total load is less than 15A, so you need to size the wire to the breaker panel accommodate 15A (or whatever your likely amperage is) for a less than 3% drop for the length of the wire from the battery through the switch, to the panel. On a Potter 19, I would guess this to be less than 30 feet. AWG #8 will accommodate this.

Then use an appropriately sized breaker and wire to run to each individual circuit.

BTW- I agree about the metal P-clips. They should at least be insulated.


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

USCG Licensed OUPV Captain, ASA 101/103/104/105/106/118 Instructor - Also certified in Marine Electrical Systems


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
eherlihy is online now  
Quote Quick Reply Share with Facebook
post #6 of 16 Old 03-04-2016
Learning the HARD way...
 
eherlihy's Avatar
 
Join Date: Jan 2007
Location: Boston / Ft Myers Area
Posts: 5,073
Thanks: 258
Thanked 170 Times in 167 Posts
Rep Power: 10
 
Re: Need help with wiring boat.

MRBF:

Block - attaches directly to battery terminal:


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

USCG Licensed OUPV Captain, ASA 101/103/104/105/106/118 Instructor - Also certified in Marine Electrical Systems


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
eherlihy is online now  
Quote Quick Reply Share with Facebook
post #7 of 16 Old 03-07-2016
Senior Member
 
RichH's Avatar
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 4,228
Thanks: 37
Thanked 233 Times in 220 Posts
Rep Power: 18
   
Re: Need help with wiring boat.

Here's a wiring calculator for sizing the correct wire gage based on amps and distance the wiring run; also good for fuse & circuit breaker sizing: Circuit Wizard - Blue Sea Systems

Note: youll have to click on the legal/risk acceptance clause (I agree, etc.) before the calculator is enabled and active.
RichH is online now  
Quote Quick Reply Share with Facebook
post #8 of 16 Old 03-07-2016
Senior Member
 
Join Date: Feb 2011
Location: San Francisco Bay area
Posts: 3,035
Thanks: 9
Thanked 76 Times in 76 Posts
Rep Power: 6
 
Re: Need help with wiring boat.

BTW, if you're looking to calculate voltage drops, here is a handy calculator :

Voltage Drop Calculator Genuinedealz.com

It's also a very good supplier of marine electrical supplies. I particularly like their custom cable service, where they add the crimps etc. for you. I got them to make a bunch of new heavy-gauge battery cables, and the quality is really good.

If I put into the calculator a 12 foot run, and 15 amps of current, you need 8 gauge or thicker to stay under a 3% voltage drop. At 30 amps you need 6 gauge.

Bristol 31.1, San Francisco Bay
MarkSF is online now  
Quote Quick Reply Share with Facebook
post #9 of 16 Old 03-10-2016 Thread Starter
Senior Member
 
Join Date: Feb 2002
Location: Oceanside CA
Posts: 1,168
Thanks: 28
Thanked 25 Times in 25 Posts
Rep Power: 15
 
Re: Need help with wiring boat.

So for now I have decided to skip the battery switch and go straight to the panel from the one battery I have to install for now. I stole the battery cable coming from the back of the boat where the alternator on the 4 stroke used to be (boat no longer has a 4 stroke). I went down to the chandlery where they had all the tools I need to alter this cable and make one more to fit my planned layout. Photos to follow.

Note: when I took off this battery cable it was the one that everyone was concerned about with the uninsulated P-clip, there was not two wires in the one ring connector it just looked like it. However when I removed all the old wiring there was triple wires attached to ring connectors at the negative terminal on the battery to provide the negative all of the circuits. It was quite the mess on a very simple wiring system.

Now I have a question on fuses. This is for another boat my Ericson 32 which just had a battery charger failure and I found both batteries dead.

Should I even try to recharge a battery found completely dead or buy new batteries?

Initially I thought the MRBF fuse on each battery protected the system through the battery switch and to the dc switch panel. But realized if I have the battery switch on "BOTH" There is a potential for each battery to provide half of a amperage and exceed the capacity of a wire coming out of the battery switch. Should there also be a MRBF or another type of fuse on the output from this switch to protect that cable from getting too much amperage?

Jordan
West Wight Potter 14 "Lemon Drop"
Oceanside CA
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.
jephotog is online now  
Quote Quick Reply Share with Facebook
post #10 of 16 Old 03-10-2016
░░░░░░░░░░
 
Join Date: Apr 2006
Posts: 12,176
Thanks: 6
Thanked 170 Times in 167 Posts
Rep Power: 12
   
Re: Need help with wiring boat.

Each power source (battery, alternator, shore power charger, etc.) should have a fuse located on the output, and fused at whichever is less: The size of the load it is connected to, ~110~120% of the maximum output of the device, or the ampacity of the wire. This last is based on the wire size and type and can be looked up online.

Forget the *switch*, you don't fuse power sources there. You fuse them at the source.
hellosailor is offline  
Quote Quick Reply 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:
OR

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
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Wiring my boat creelclmsn Electrical Systems 4 10-04-2014 12:09 AM
Introduction to wiring a boat? CatfishSoup Electrical Systems 13 01-19-2009 09:12 AM
old boat wiring KasbeKZ Gear & Maintenance 20 10-17-2008 01:35 PM
Wiring my boat for cable TV Perithead Gear & Maintenance 11 04-18-2008 01:34 PM
Wiring the boat - labeling Windborn Gear & Maintenance 15 03-11-2008 08:29 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome