Fuse size & wire gauge
- Thread starter bmcminn
- Start date
Your boat looks like it has been re-wired. There is a piece of starboard or plastic over where the factory wiring was, and then there is the West Marine panel (I have used these for auxiliary panels in some boats). Where does the 12 volt power come from?
The boats are often "under wired" from the factory--but there is almost always a circuit breaker near the battery. That is called for by ABYC and NMEA standards.
How long is the run from the battery to the panel where you want to run the wire? Twice that distance is the length you use to calculate the wire size, for the amp draw anticipated. In the 22 or 19, I would figure on at 30 amps for most boats. Lets say that there is abut 25' (round trip) from the battery to the panel. For less than 3% voltage drop (critical, and I recommend that for radio and electronics) it would be #6 wire and 30 amp fuse. Practically, however, I suggest #8 wire, because it will be extremely unusual you will be using more than 10 to 15 amps.
The draw of the USB port is only a couple of amps (@12 volts)
There are several places that have wire size, length and amp tables: . Here is an article from the Blue Seas site.
I download and print out this table and keep it in the boat manual.
The boats are often "under wired" from the factory--but there is almost always a circuit breaker near the battery. That is called for by ABYC and NMEA standards.
How long is the run from the battery to the panel where you want to run the wire? Twice that distance is the length you use to calculate the wire size, for the amp draw anticipated. In the 22 or 19, I would figure on at 30 amps for most boats. Lets say that there is abut 25' (round trip) from the battery to the panel. For less than 3% voltage drop (critical, and I recommend that for radio and electronics) it would be #6 wire and 30 amp fuse. Practically, however, I suggest #8 wire, because it will be extremely unusual you will be using more than 10 to 15 amps.
The draw of the USB port is only a couple of amps (@12 volts)
There are several places that have wire size, length and amp tables: . Here is an article from the Blue Seas site.
I download and print out this table and keep it in the boat manual.
Here is a different, maybe simpler approach:
That panel which I agree is probably non OEM is made by Blue Seas but is labeled West Marine. Here is a data sheet for three models, yours being the 6 breaker model. Click on the link to a pdf for specs and wiring diagram.
https://www.westmarine.com/buy/west-mar ... cordNum=26
All of the breakers seem to be 15A.
Since the bottom breaker looks like it is unused and the cigarette lighter and USB outlets you want to wire to is a few inches away, then run a 14 gauge wire from the bottom breaker to the pos cigarette lighter terminal and then in parallel to the pos USB terminal. There should be a negative buss close by, so wire the negative the same way from that bus.
David
That panel which I agree is probably non OEM is made by Blue Seas but is labeled West Marine. Here is a data sheet for three models, yours being the 6 breaker model. Click on the link to a pdf for specs and wiring diagram.
https://www.westmarine.com/buy/west-mar ... cordNum=26
All of the breakers seem to be 15A.
Since the bottom breaker looks like it is unused and the cigarette lighter and USB outlets you want to wire to is a few inches away, then run a 14 gauge wire from the bottom breaker to the pos cigarette lighter terminal and then in parallel to the pos USB terminal. There should be a negative buss close by, so wire the negative the same way from that bus.
David
I may have mis-interputed the question. You want to know wire gauge and Fuse for the USB and cigarette lighter type of receptacle ? I thought you wanted to know the fuse and wire gauge from wiring the panel to 12 volts from your battery.
In that case I would say that 10 amps would do for the cigarette lighter type and 5 amps for the USB--but if you have a 15 amp breaker which you will dedicate from the panel I would just use that. For these short runs (only a few inches) #14 wire would be fine.
I doubt that this panel was made by Blue Seas. All of their panels are a higher quality, use a standard A frame circuit breaker made by Carling. I suspect that this panel is made in China for West Marine.
In that case I would say that 10 amps would do for the cigarette lighter type and 5 amps for the USB--but if you have a 15 amp breaker which you will dedicate from the panel I would just use that. For these short runs (only a few inches) #14 wire would be fine.
I doubt that this panel was made by Blue Seas. All of their panels are a higher quality, use a standard A frame circuit breaker made by Carling. I suspect that this panel is made in China for West Marine.
thataway":2xq6rl6k said:
Well, virtually everything is ultimately made in China.
The reason why I said it was a Blue Seas panel, is when you go to West Marine's website and find that product, then click on the link for Specifications and Wiring, it takes you to a Blue Seas pdf document.
That makes me think that Blue Seas designed and specified the panel, even though some Chinese shop makes them.
David
I would use 10 A fuse minand 10 or 12 G marine grade wire.
There are several
types of cig lighter outlets and would review all of the Blue Seas items for current and future use
ex
https://www.bluesea.com/products/1478/3 ... SB_Charger
or https://www.bluesea.com/products/4365/W ... B_Chargers
full list
https://www.bluesea.com/products/1011/1 ... ash_Socket
There are several
types of cig lighter outlets and would review all of the Blue Seas items for current and future use
ex
https://www.bluesea.com/products/1478/3 ... SB_Charger
or https://www.bluesea.com/products/4365/W ... B_Chargers
full list
https://www.bluesea.com/products/1011/1 ... ash_Socket
Strange, because on my computer the pdf document says West Marine in multiple places.... I didn't sea "Blue Seas" anywhere. But I may have missed it?
Yes, many items are made in China--but there are quality items, vs cheap items. I tend to equate Blue Seas with quality. Blue Seas is a Power Product company, and their other lines are also high quality products, like Mastervolt, ProMariner and Ancor.
Looking at the original photos, there is the face of the added plastic panel which has the west marine breaker panel. On the second photo is a picture of a Fuse block with 12 fuse positions, which appears to be a Blue Seas product, but without its proper cover. That has mostly less than 16 gauge wire coming off--and what I would best guess is 10 gauge at the max feeding it. Most of these Fuses seem to be 3 to 5 amps
Is this the point where bmcminn wants to take power from for the cigarette lighter plug and UWB or is it the West Marine breaker panel, which appears to have two unlabeled (unused?) breaker slots (the lowest)? So where does bmcminn wish to take the power from. This would have bearing on the size of the wire. We would also want to know the distance the wire would run--as per my original post. But I would not put any more than 10 amps on this particular cigarette lighter type of plug. I don't see any indication that this is a Blue Seas plug or USB port--there are many of these ports available on Amazon etc--and many are not rated for more than 10 amps.
Brent--why do you feel that the cig lighter plug and USB port should be moved?
The standard C Dory panel (which appears to have been removed) in most boats has a plug in this location. In my boat, I have a USB 2 plug (with a 2 hour timer--and this may be important--because of over charging batteries) to the right of my helm. It is very handy to recharge or keep charged I pad for navigation (which many C Brat use). In our case we have 2 other stations, but in a 19, this seems like the logical place for the USB charger port.
Micahbigsur@msn.com
New member
You have a whole side of your fuse block open for use, the top screws are obviously for ground and the lower row the 12v positive.
I wire my cigarette plug outlets for a US auto standard 15 amp fuse and use 12 ga wire.
The latest USB 3 outlets put out a little less than an amp so I use a 2.5 amp fuse (sometimes hard to find, a 5 would be good on the double USB) and 14 or 16 ga wire depending on the run.
I always add more to the boat using small sub-fuse blocks in different locations which themselves run off a 20 amp main fuse.
Your main fuse block behind the helm should have at least a # 10 ga wire running up from the 25 or 30 amp fuse within 18" of the battery distribution multi-post. (Mine came with a 10 standard, I added 3 more #8 duplex up to run my new systems. (Required for the solar, battery charger and watermaker fuse block)
I use the better protected, neater, duplex wire for 95% of my wiring.
A lot of the cheap Chinese crimp connectors are worthless junk, try to use Ancor or equivalent. I lock out corrosion in all my connections with diaelctric silicone grease. Use adhesive shrink tube anywhere where it can get moist.
Good luck with your project, it should be fun!
I wire my cigarette plug outlets for a US auto standard 15 amp fuse and use 12 ga wire.
The latest USB 3 outlets put out a little less than an amp so I use a 2.5 amp fuse (sometimes hard to find, a 5 would be good on the double USB) and 14 or 16 ga wire depending on the run.
I always add more to the boat using small sub-fuse blocks in different locations which themselves run off a 20 amp main fuse.
Your main fuse block behind the helm should have at least a # 10 ga wire running up from the 25 or 30 amp fuse within 18" of the battery distribution multi-post. (Mine came with a 10 standard, I added 3 more #8 duplex up to run my new systems. (Required for the solar, battery charger and watermaker fuse block)
I use the better protected, neater, duplex wire for 95% of my wiring.
A lot of the cheap Chinese crimp connectors are worthless junk, try to use Ancor or equivalent. I lock out corrosion in all my connections with diaelctric silicone grease. Use adhesive shrink tube anywhere where it can get moist.
Good luck with your project, it should be fun!
Micahbigsur@msn.com
New member
It is curious to me why there is a yellow glass fuse holder wired into the 3rd fuse block slot up. Glass fuse holders inline can have more connection resistance than the easy to check blade fuses. Maybe the blade fuses don't go low enough for whatever device is wired in? If I can I cut out the inline fuses that come inline with a lot of electronics if it is a size that can be directly wired to a fuse in the block, avoiding a double fused line.
West Marine does not carry (or auto supplies) the full range of the ATC blade fuses, I find them on Amazon. They vary in quality avoid the cheap off brands.
I use silicone diaelctric grease on the blades of the fuses to avoid salt corrosion.
West Marine does not carry (or auto supplies) the full range of the ATC blade fuses, I find them on Amazon. They vary in quality avoid the cheap off brands.
I use silicone diaelctric grease on the blades of the fuses to avoid salt corrosion.
Hi everyone. This is why I need to make a wiring diagram. I'll get to it as soon as...oh wait.
Maybe after Christmas?
Anna is working late, so tonight after I get the girls fed/bed I'll have some time to set this up and post a couple of pictures that are easier to see. And I'll try to answer any of the questions about what is in the photos. I'm sure it's all pretty ordinary, this one got re-wired a couple years ago from bow to tail-rotor.
Thanks for all the good stuff to ruminate on.
Maybe after Christmas?
Anna is working late, so tonight after I get the girls fed/bed I'll have some time to set this up and post a couple of pictures that are easier to see. And I'll try to answer any of the questions about what is in the photos. I'm sure it's all pretty ordinary, this one got re-wired a couple years ago from bow to tail-rotor.
Thanks for all the good stuff to ruminate on.
BrentB":2wehcolq said:
I should have clarified--any wires which go near the wheel or would be in the way when you operate the boat, can be held out of the way with velcro. For instant in the RV, I have 5 USB and Power cables going to instruments which are just below the driver's line of vision. All of these are secured with small velcro ties to keep them in place, and not interfere.
We have always added a number of extra 12 volt cigarette lighter type of receptacles . There are some which are not quite standard, and the plug will
either bind (in some cases not go in at all) and others where the fit is too loose, and the plug will not stay in.
For the ARB freezer in the cockpit, it comes with a cig. lighter plug, but you can screw off the outer part of the plug, and then put in a two wire plug into a two wire recptical, and the whole thing locks together with a wheel and cam, so the freezer will not come unplugged. If we have higher draw connections, we use "Anderson Power Pole Connectors" which give a positive "latch" and come in 15, 30 and 45 amps. The 30 and 45 will have at least #10, and #6 wire respectively.
I really appreciate everyones help on this one, thanks. An eventual project will be to build a little access panel to tuck everything away behind.
Micah, the yellow glass fuse is 3 amps and is inline to the Garmin GPS and connects to a 3A blade fuse on the fuse block. Any idea why?
Also, do you know why I have a ground bus bar in addition to the ground portion of the fuse block? I ran the positive from the 12V and USB to the fuse block and used 15A and 5A fuses and ran the negative to the ground bus bar. Should I have grounded them on the fuse block? It all works...
One last question, kinda two really, why didn't the person who wired it heat shrink the connectors? And should I (someday) pull them and heat shrink them and also use dielectric on all that exposed stuff?
Thanks. It all worked on my trip and made it much more comfortable.
Micah, the yellow glass fuse is 3 amps and is inline to the Garmin GPS and connects to a 3A blade fuse on the fuse block. Any idea why?
Also, do you know why I have a ground bus bar in addition to the ground portion of the fuse block? I ran the positive from the 12V and USB to the fuse block and used 15A and 5A fuses and ran the negative to the ground bus bar. Should I have grounded them on the fuse block? It all works...
One last question, kinda two really, why didn't the person who wired it heat shrink the connectors? And should I (someday) pull them and heat shrink them and also use dielectric on all that exposed stuff?
Thanks. It all worked on my trip and made it much more comfortable.
bmcminn":7bqfi9vg said:
I would say that if you have exposed screw terminals in an area that does not have much risk of water contact heat shrink joints and connections aren't going to mean a whole lot. The original wiring of the boat did not use heat shrink lugs and splices anywhere I can tell.
On my boat stuff I add in or directly adjacent to the cockpit gets heat shrink. Newer stuff under the sink usually gets it too (lately because I bought bags of heat shrink splices). Stuff elsewhere doesn't. I'm not about to redo everything just to put heat shrink lugs on stuff.
If it ain't broke don't fix it.
Micahbigsur@msn.com
New member
Yes unless in a damp or salt spray area no need to use heat shrink, though anything you add you can use crimp terminals that have the built in heat shrink.
Many things get added at different times in boats, if someone wanted an added ground they add a buss bar, that is fine, that one is a good one of a newer Blue-Seas style. It is neater if both the +&- are tied in close together. Make sure that both negative bars are tied together directly and not all the way back through the batteries, then they are essentially one.
The yellow glass fuse came with the unit so it could be tied directly into the positive 12v, in your system it is extraneous, adds another problem point just directly from the blade fuse is better...but make sure in your manual that it is a normal glass fuse not a "fast blow" or other weird fuse which is unlikely. If the fuse in it just says 3 amp it is the same as the blade fuse.
Try to bundle parallel wires with zip ties for neatness to avoid the rats nest look but I would not rewire what is working, adding new wires, run them alongside others and tie them together also neater, every time you undo a screw or add something use dielectric.
Good luck!
Many things get added at different times in boats, if someone wanted an added ground they add a buss bar, that is fine, that one is a good one of a newer Blue-Seas style. It is neater if both the +&- are tied in close together. Make sure that both negative bars are tied together directly and not all the way back through the batteries, then they are essentially one.
The yellow glass fuse came with the unit so it could be tied directly into the positive 12v, in your system it is extraneous, adds another problem point just directly from the blade fuse is better...but make sure in your manual that it is a normal glass fuse not a "fast blow" or other weird fuse which is unlikely. If the fuse in it just says 3 amp it is the same as the blade fuse.
Try to bundle parallel wires with zip ties for neatness to avoid the rats nest look but I would not rewire what is working, adding new wires, run them alongside others and tie them together also neater, every time you undo a screw or add something use dielectric.
Good luck!
I agree with the above, except for one factor. That is I do use heat shrink where ever possible, especially if the boat is used in salt water. Just the salt air has enough salt to make corrosion more likely in the wires.
I have rewired 20 year old boats, which were kept in salt water, and even the Ancor tinned wiring which was in the interior had some corrosion. Any non tinned wire had extensive corrosion. The heat shrink terminals (there are some decent ones from China which are cheaper than Ancor in bulk), work very well, and you don't have to add adhesive heat shrink tubing, unless you damaged the outside of the insulation with the crimper.
As Ssobol, I have boxes of all size of adhesive heat shrink--cheaper if you buy in bulk..
I would not undo, unless you want to for neatness at this point. I would use the dielectric grease with all screw contacts.
As for the negative bus bar: it was probably put in for those items on the outboard size of the console. When you go along, you may want to shorten the coiled wire (except the outboard harness)
I have rewired 20 year old boats, which were kept in salt water, and even the Ancor tinned wiring which was in the interior had some corrosion. Any non tinned wire had extensive corrosion. The heat shrink terminals (there are some decent ones from China which are cheaper than Ancor in bulk), work very well, and you don't have to add adhesive heat shrink tubing, unless you damaged the outside of the insulation with the crimper.
As Ssobol, I have boxes of all size of adhesive heat shrink--cheaper if you buy in bulk..
I would not undo, unless you want to for neatness at this point. I would use the dielectric grease with all screw contacts.
As for the negative bus bar: it was probably put in for those items on the outboard size of the console. When you go along, you may want to shorten the coiled wire (except the outboard harness)