Reply
 
Thread Tools Display Modes
 
Old 04-05-2016, 12:32 PM   #1
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 180
Overcurrent protection

All,

I would like to install overcurrent protection for the two house banks. 4awg wire was used with a temperature rating of 105c, but the wiring for the banks is bundled. It is my understanding from reading Nigel Calder that an 80amp breaker of fuse would be appropriate on each circuit as they run in the engine space, but then multiply by .7 because they are bundled so ~56 or rounded up to 60a. Calder states that the fuse or breaker should not be right with the batteries due to fumes and corrosion. However, it seems to me that the easiest way would be to put a fuse right on the battery terminal and then run the cable from it. What is the correct way to handle this?

Thanks for the help! This forum has already been an incredible wealth of information!

What about these MRBF Terminal Fuse Blocks combined with 60a fuses? http://www.defender.com/product3.jsp...0030&id=983740
__________________
Advertisement

Panhandler is offline   Reply With Quote
Old 04-05-2016, 01:07 PM   #2
Guru
 
Bacchus's Avatar
 
City: Seneca Lake NY
Country: US
Vessel Name: Bacchus
Vessel Model: MS 34 HT Trawler
Join Date: Nov 2014
Posts: 1,411
Quote:
Originally Posted by Panhandler View Post
All,

What about these MRBF Terminal Fuse Blocks combined with 60a fuses? Blue Sea Systems Single MRBF Terminal Fuse Block
I think they are the way to go... I believe ABYC states overcurrent protection should be w/in 7 inches from batt'y and for large cables i think they are easier than inline (no addn'l crimps req'd)

HopCar here on TF should be able to supply them if interested.
__________________

__________________
Don
MS 34 HT Trawler
"Bacchus"
Bacchus is offline   Reply With Quote
Old 04-05-2016, 03:49 PM   #3
Guru
 
kchace's Avatar
 
City: Brookline, NH
Country: USA
Vessel Name: Blue Heaven
Vessel Model: Albin 43 classic double cabin, twin 135 Lehmans
Join Date: Sep 2013
Posts: 761
Quote:
Originally Posted by Panhandler View Post
All,

I would like to install overcurrent protection for the two house banks. 4awg wire was used with a temperature rating of 105c, but the wiring for the banks is bundled. It is my understanding from reading Nigel Calder that an 80amp breaker of fuse would be appropriate on each circuit as they run in the engine space, but then multiply by .7 because they are bundled so ~56 or rounded up to 60a. Calder states that the fuse or breaker should not be right with the batteries due to fumes and corrosion. However, it seems to me that the easiest way would be to put a fuse right on the battery terminal and then run the cable from it. What is the correct way to handle this?

Thanks for the help! This forum has already been an incredible wealth of information!

What about these MRBF Terminal Fuse Blocks combined with 60a fuses? Blue Sea Systems Single MRBF Terminal Fuse Block
The *conductors* running through engine spaces should be derated, and derated further if they are bundled, but regardless of what the wires can "carry" it is prudent to limit the fuses to the max expected circuit current. If after doing the "derating" math the max conductor current is not sufficient, then you will need to upsize the conductors or not bundle them or don't run them through engine spaces.

I have swapped all my battery fusing over to those "Terminal fuses" They are ignition protected, don't require extra wiring, available in 30-300A sizes and take up the least amount of space. BTW - they are made by Buss and available at Delcity for a fraction of the cost from Blue Sea Systems.

Marine Rated Battery Fuse Block

Ken
kchace is offline   Reply With Quote
Old 04-05-2016, 11:20 PM   #4
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 180
Thank you both. Looks like the way to go.
__________________
SeaTriscuit.com - Abandoning the real world for St Thomas with a Craigslist trawler, little experience, and two cats.
Panhandler is offline   Reply With Quote
Old 04-06-2016, 09:04 AM   #5
Guru
 
Phil Fill's Avatar
 
City: Everett Wa
Country: US
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,919
Your boat might already have them as they been recommended back in the 1970. The eagle is 1978 and has them. 600 amp for the start and 60 for the house and 30 for the inverter about a foot from the battery. Had an insurance audit and the first thing check where the battery fuses. We did not have one on the inverter. Another was AC breaker between the shore power boat plug and the main planel selector switch which the Eagle did not have, and most older boats do not. Not having is the cause of many boat fires. He found 19 problem items which we had 60 days to correct bring up to code.
Phil Fill is offline   Reply With Quote
Old 04-06-2016, 10:29 AM   #6
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 180
Quote:
Originally Posted by Phil Fill View Post
Your boat might already have them as they been recommended back in the 1970. The eagle is 1978 and has them. 600 amp for the start and 60 for the house and 30 for the inverter about a foot from the battery. Had an insurance audit and the first thing check where the battery fuses. We did not have one on the inverter. Another was AC breaker between the shore power boat plug and the main planel selector switch which the Eagle did not have, and most older boats do not. Not having is the cause of many boat fires. He found 19 problem items which we had 60 days to correct bring up to code.
Thanks, Phil. Purchase survey indicated no overcurrent protection but she does have an AC breaker between shore power and the main panel. It's an odd combination of recent upgrades and old holdovers! I'll take a more serious look at the wiring when we get her back to our dock in Pensacola from Melbourne. It seems as if some simplification may be in order, particularly in terms of isolating batter banks. The big Cat has two 8D starting batteries, the gen has two big starting batteries, and then there are two house banks...all charged by one charger.... Love your boat, btw!
Panhandler is offline   Reply With Quote
Old 04-06-2016, 10:57 AM   #7
Guru
 
Phil Fill's Avatar
 
City: Everett Wa
Country: US
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,919
Quote:
Originally Posted by Panhandler View Post
Thanks, Phil. Purchase survey indicated no overcurrent protection but she does have an AC breaker between shore power and the main panel. It's an odd combination of recent upgrades and old holdovers! I'll take a more serious look at the wiring when we get her back to our dock in Pensacola from Melbourne. It seems as if some simplification may be in order, particularly in terms of isolating batter banks. The big Cat has two 8D starting batteries, the gen has two big starting batteries, and then there are two house banks...all charged by one charger.... Love your boat, btw!
We stayed at Orange beach two weeks ago. We are looking at different areas for the winter. Puget sound on the boat in the summer and winter south. Make sure you added the AC breaker, shore and gen set. Make sure they are double throw.
Phil Fill is offline   Reply With Quote
Old 04-06-2016, 11:11 AM   #8
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 180
Quote:
Originally Posted by Phil Fill View Post
We stayed at Orange beach two weeks ago. We are looking at different areas for the winter. Puget sound on the boat in the summer and winter south. Make sure you added the AC breaker, shore and gen set. Make sure they are double throw.
Thanks, I'll double check. We'll rent you some cheap dock space in Pensacola!
__________________

Panhandler is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 02:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012