# HOW-TO-GUIDE: Wiring your tin boat...Where to begin?



## HOUSE

*Wiring your tin boat… where to begin? A how-to guide for rookies.*

When I first began the wiring part of my boat mod, I was totally overwhelmed by the thought of all of the electrical components and where to begin. I knew that I wanted to do, but I wasn’t sure how to work with fuses, wire gauges, splicing wire, etc. I also didn’t know what anything was called! Thankfully, many helpful contributors on this forum answered my questions and really helped me figure out what I was doing. While I still am pretty novice at this stuff, I decided to create a guide to help other electrical-noobs get a jump-start on their electrical work. I hope this guide gets you headed in the right direction. Since this guide is written by an electrical dummy and geared towards other beginners, I will try to keep it updated as more experienced users chime in on the forums. *(Again, I am not an expert in electrical work, this is merely a starter guide to help you get started.)*

-So you are ready for the electrical work on the boat. Where do you begin? First off, I would start by writing down all of your electrical components that are going to need wires run to them. Consider including these devices: Front bow light, rear anchor light, fish finder(s), trolling motor(s), & a bilge pump for starters. 

-For the next step I suggest drawing a picture of your boat so that you can visualize where each device will sit. This will help you determine how to run wires to each device. I used MS Paint for my design which is a free program on most computers. You can also use this generic boat diagram below:
Generic Boat diagram:






Once you’ve sketched out a plan, it’s time to figure out how to put everything together. The biggest obstacle I faced was not knowing the names of the various electrical parts that I needed. To help figure out the terminology, I downloaded a catalog from BlueSea.com who makes a lot of marine electrical components. You can view their brochure by visiting their website: *https://www.bluesea.com* or directly download the pdf brochure here: https://bluesea.com/files/resources/catalogs/2012_catalog_print.pdf

While you are making your shopping list, you may want to create a chart with each of your device’s recommended fuses since you will need to protect each of these devices (and the wire running to them!) with a fuse. It’s not as difficult as it sounds if you can find the product manual online. Most lights are 1-2amps, most fish finders are 3-5amps, and most trolling motors are 50-60amps. On a side note, a lot of people use a circuit breaker instead of fuses since they can reset themselves if they trip unlike a fuse that has to be replaced. Most mods I’ve seen protect the trolling motor that way. I used a $10 one from Amazon: https://www.amazon.com/Rig-Rite-Man...TF8&coliid=I1IWUAJZL3G1N4&colid=2IVRY592PVL4E. (Note: most people refer to circuit breakers as “CB’s” in their mods.)

I also bought a switch board to turn everything on and off from my captain’s chair. This switch board was pre-made and actually included the fuses I’m using. (I did have to swap out some of the fuses to match my particular devices, however, since most of the included fuses were 5 or 15amps.) There are a lot of options out there, and most forum posts had good things to say about Cabella’s switches, and bad things to say about Bass Pro Shop’s switches. Just be careful that you buy a waterproof one or have plans to seal it properly into some sort of sealed box. I just ordered a generic switch from Ebay and sealed it myself. (Search for “marine switch panel”, for example.) You also don’t have to buy one with fuses. It is not too difficult to buy a little “fuse block” and wire everything to that. (Note: My understanding of fuses is that you are really protecting the wire from melting in the event of a short, and you want the fuse to pop before anything overheats. You want to keep fuses as close to the positive power source as possible, and match the amps to the device you are protecting.)
(Note: I forgot to protect the switch board itself with a fuse/circuit breaker. I had a 10ft AWG 6gauge wire running from the battery to the switch that was not protected! doh! Thanks to the forum-pros I was able to catch this before anything went wrong. I have to add a fuse to it still.)

As to other components you will likely need in your electrical project, I will use my mod as an example since it is a pretty basic electrical scheme: 1 front battery wired to a trolling motor, fish finder, bow light, stern light, and LED lights. Personally, I wanted to be able to remove my battery easily, so I installed a positive and negative connection “post” or “block” that I could wire everything to near the battery. That way I can just disconnect one wire off each battery lead and yank it out. I bought “battery lead cables” for this which are basically just #6gauge wires with fancy clamps on the end to attach to the battery. I attached the positive lead to a BlueSea.com “PowerPost cable connector” that is rated for high current to go through it (LINK). It is basically just a fancy bolt that is waterproof. For the negative block, I installed a busbar (LINK) from Amazon.com that is rated to handle high amps. This busbar is basically just a long piece of metal that I can screw down multiple wires to, and then run one wire back to my battery. 
If you don’t want to buy 2 “battery lead wires” off the battery (LINK), I read that #6gauge wire would also work here. I just didn’t want to have to splice the cable and attach some sort of end piece to it. Also, the battery lead cables were only $4 at my local hardware store.

The rest of the wiring was pretty simple…I had to run pretty thick wire back to my switch box and fuses, so I used #6guage wire. Since my LEDs came with pretty flimsy wire, I had to solder and shrink wrap individual #14gauge wires to each light (real pain in the butt), so I used 2 busbars here as well to tie all of the positive and negative leads together. I replaced the proper fuses out of my switch box and ran a negative ground back up the battery. Here is a picture of my boat’s wiring for reference, and yes, there probably is a better way to do what I did, but it works!: 




.

Good luck!!!

-House

p.s. Below are some very useful links and references below:
.
My shopping list:
#14gauge wire (17ft @ Home Depot = $4.99), (30ft @ Autozone = $5.99), (20ft @ Oreilly = $6.50)
#6gauge wire (expensive @ $2 per foot)
Wire lead cable x2: ($4 @ O’riely’s)
50amp circuit breaker: $9 @ Amazon.com
PowerPost cable connector: $12 @ Amazon.com
Busbar x 3: $11 @ Amazon.com
Fused Switch Panel: $30 @ ebay

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*
LINKS & REFERENCES:*

*FORUM THREADS:* Here are some of the helpful Tinboat.net forum threads that I bookmarked along the way that helped me out:
Simple wiring questions for my first Mod!! Please help! - https://www.tinboats.net/forum/viewtopic.php?f=5&t=23550
Grounding a toggle switch - https://www.tinboats.net/forum/viewtopic.php?f=5&t=14685&p=150839&hilit=Grounding+a+toggle+switch#p150839
Splicing 6 gauge wire - https://www.tinboats.net/forum/viewtopic.php?f=5&t=11724&hilit=Splicing+6+gauge+wire
Bow light 14 ga? - https://www.tinboats.net/forum/viewtopic.php?f=5&t=18499&hilit=Bow+light+14+ga%3F


*ARTICLES:*
Here is a good introductory guide to boat electronics by Don Casey that is a good place to start: https://www.boatus.com/boattech/casey/05.htm
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*Electrical Connections by Don Casey*
(Actual article
Whether adding new electrical gear or rewiring something already aboard, the requirements for a reliable and safe electrical connection are the same. You need the right wire, the right terminal fittings, and a couple of inexpensive hand tools. 
Wire
A wire could hardly find a more hostile environment than aboard a boat. On-board wiring is salted and doused, shaken and whipped, crushed and abraded, exposed to sunlight, subjected to heat, and coated with petroleum. Neither lamp cord nor house wiring will long endure these conditions. 
Choose your wire carefully. Never use solid wire on a boat. Wave-or motor-induced oscillations eventually fracture solid wire. Boat wiring must have the flexibility stranding provides. Boat-builders save a few dollars using type 2 wire, but a boat owner should use only the most flexible wire, called type 3. 
The wire must be copper, but even copper corrodes in the marine environment, and corrosion is the primary cause of electrical failures on a boat. Plating each strand of the wire with a thin coat of tin-called tinning--dramatically improves corrosion resistance. The additional cost of tinned wire is nominal, the benefits substantial. Under normal circumstances use only tinned wire. 
Stranded single-conductor wire is called hook-up or primary wire. Since most after-construction wiring requires two wires, duplex wire is more convenient and provides the added safety of a second layer of insulation. The best choice for most 12-volt wiring projects is duplex safety wire, where the twin conductors are red (positive) and yellow (ground). Making the ground wire yellow rather than black reduces the likelihood of confusing a DC ground wire with an AC hot wire-also black. 
Boat cable
In recent years wire designed for the marine environment has become widely available to boat owners. This wire is known as boat cable. Unfortunately the Underwriter's Laboratories standard that defines boat cable, UL 1426, is less stringent than commonly thought. Boat cable can be type 2, tinning is not a requirement, and the heat rating of the insulation can be quite low. When you select boat cable, type 3 is better, tinning is essential, and you want the highest heat rating-designated on the jacket as BC5W2 (105¡C in a dry environment, 75¡C wet). Tinned boat cable from a reputable supplier is your best choice for all wiring needs. 
*Size*
As with water through hose, electricity flows more easily through larger wire. It is essential to size wire for the maximum current flow you expect it to carry. If the wire feeds a single item, the current requirements will be shown on a label or plate on the appliance, or in the accompanying manual. If the rating is in watts, divide it by 12 (assuming a 12-volt electrical system) to convert the rating to amps. When the wire is part of a circuit that supplies several appliances, the potential current through the wire is the sum of the current requirements of every appliance on the circuit. For example, if a circuit is comprised of six 25-watt cabin lamps, the wire will be carrying about 12 amps ([25 watts Ö 12 volts] x 6) when all the lights are on. 
To size wiring, you need the wire length from the power source to the appliance(s) and back to the power source. Doubling the straight line distance to the battery or electrical panel is not adequate. You must determine the actual length of the wire by measuring along the path it will follow-up, over, and around. It is not unusual for a wire run to be more than twice the straight-line distance. 
Some voltage is used up pushing the current through the wire. This loss, called voltage drop, should not exceed 3%. The table shows what size wire is required to deliver adequate voltage to the other end. Use the potential current draw to select the row, the round trip wire length to select the column. The number where these two intersect is the wire size you need. Electrical wire appropriate for marine use will have the gauge designation printed on the insulation. The smaller the gauge number, the larger the wire diameter. Always buy wire at least a foot or two longer than your measurement. You can easily shorten the wire after it is installed, but lengthening it requires a highly undesirable splice. Each wire should be a single continuous run between terminals. 

*Connections*
Other than chafe or lying against hot metal, wires rarely experience failures in the middle of a wire run. Almost all wiring problems occur at the connections. Never twist wires together to make a connection, and never wrap a bare wire around a terminal screw. You will minimize wiring problems if you terminate all wire ends with crimp connectors. 

Selecting the proper connector requires that you match it to the wire gauge and to the size of the terminal screw. Ring terminals are your best choice unless the terminal screw is captive. In that case, use flanged spade connectors. 
Use butt connectors for appliances supplied with wire leads instead of terminals. Step-down butt connectors let you connect heavy supply wires to lighter leads. To simplify servicing, it can be a good idea to make the connection with blade or snap connectors instead of butt connectors. Three-way connectors are useful for tapping into an existing circuit. 
Terminals used on a boat must always be copper, never steel or aluminum, and like the wire, they should be tin-plated to resist corrosion. 
Tools
Nine times out of ten, stripping insulation with a pocket knife results in nicked wire, which opens the door to corrosion. And you simply cannot make a dependable crimp connection with a pair of pliers. Every boat owner should own a wire stripper and a good-quality crimper. The cost is nominal. Strippers sold by auto supply and hardware stores are for SAE wire, which is about 10% smaller than AWG, so these strippers will nick AWG wire. Be sure the wire stripper you buy is intended for AWG wire. 
An inexpensive pliers-type crimper is more than adequate for a few connections, provided you make a few practice crimps first. But if you will be making a lot of connections, a ratchet crimper offers the benefit of consistency, even in the hands of an amateur. 
Crimping
Remove only enough insulation for the wire to reach the end of the barrel of the terminal. Grip the terminal in the correct die in the crimper, fully insert the wire into the terminal, and squeeze. If the barrel has a seam, the crimp indent should be opposite. 
Better terminals feature a brass sleeve that can be crimped over the insulated wire to add mechanical strength. This type of terminal is usually installed with a double crimp tool. If your crimper doesn't have a double-crimp die, crimp the terminal to the wire first, then reposition the crimper and crimp the sleeve to the insulation. 

There is only one accepted field test for a crimp terminal-pull on it. Test every crimp terminal this way. Without using any tool, grip the terminal and the wire and try to separate them. If they come apart, the crimp was bad. 
Be sure to run your wire as high in the boat as possible-to keep it dry-and support it at least every 18 inches. 
For more information about electrical connections, consult Sailboat Electrics Simplified by Don Casey. 
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*West Marine has a great website for deciding on wire thickness: LINK:https://www.westmarine.com/webapp/w...toreId=11151&catalogId=10001&page=Marine-Wire 
Marine Wire*
(Actual article
________________________________________
Even the experts have to check occasionally on the correct gauge of wire for a given marine DC load. The simplest method we've found uses the charts below. Wire gauge color codes in these charts correspond to AWG wire sizes. 
•	Select either the 10% or 3% voltage drop chart, based on the type of load you are running.
•	Next, find the current consumption of the load on the vertical axis of the chart.
•	Find the length of the circuit on the horizontal axis of the chart, noting that the length is the "round trip" distance from the panel or battery to the load and back.
•	The color of the graph at the intersection denotes the gauge of wire to use.
We've included copper wire specifications which comply with the AWG standards at the bottom. Of particular interest is the equation: Voltage Drop = Current x Length x Ohms per foot
This simple equation allows you to calculate the voltage drop for a circuit of any length and any current flow, if you know the resistance of the wire. Finally, note that the amp capacity of the wire curtails using very short lengths of wire for large current flows, as show by the "flat tops" of the 10% chart areas.
Wire gauge color codes in these charts correspond to AWG wire sizes.





These simple, proprietary graphs assume:
•	105ºC insulation rating: All Ancor wire uses 105ºC insulation rating. Lower temperature insulation cannot handle as much current (the flat tops on the 10% graph would be lower than shown)
•	AWG wire sizes: Not SAE All Ancor wire uses AWG wire sizes. SAE wire sizes are 6%-12% smaller, carry proportionally less current, and have greater resistance
•	Wires are not run in engine spaces: Maximum current is 15% less in engine spaces, which are assumed to be 20¼C hotter than non-engine spaces (50¼C vs. 30¼C).
•	Conductors are not bundled: If three conductors are bundled, reduce maximum amperage by 30%. If 4-6 conductors are bundled, reduce maximum amperage by 40%. If 7-24 conductors are bundled, reduce amperage by 50%.





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Finally, there is a *Voltage Drop Calculator* online as well to help calculate what wire gauge to use: *LINK
https://shop.genuinedealz.com/Store/Tab.aspx?tabid=2*
(Actual Genuinedealz.com article
Below you'll find a few helpers along the way to properly sizing your wire or cable. As we are primarily marine focused we have added some tables regarding the amperages as suggested by the ABYC for the marine environment. These standards might be a bit more strict then those in the automotive environment however, they err on the side of caution and were developed with safety in mind. 
The voltage drop calculator will allow you to find the percentage of voltage drop as well as the current delivered at the end of the wire run. In the boating world it is suggested:
3% max voltage drop for conductors providing power to panels and switchboards, navigation lighting, bilge blowers, main DC feeders, and any other circuit where voltage drop should be kept to a minimum
10% max voltage drop on conductors used for general lighting and other non-critical circuits
The amperage tables on the left side help to choose the correct size cable to handle the power load for which you are trying to find the correct wiring. There are individual tables for single conductor and multiple conductor runs as current carrying conductors which are bundled together will transfer heat to each other in effect reducing their safe current handling capabilities.






(Disclaimer: The information provided above is to assist you in properly sizing electrical cables for your installation. Best installation methods and practices are also very important to a safe and reliable wiring project. Please do not attempt to work with electricity without a basic knowledge of the dangers involved and please use good judgment. Seek the help of a professional electrician with specific installation questions or when in doubt. Feel free to contact us with any technical questions and we'll do our best to provide the answer or at least guide you in the right direction as to where you can get the help you need.)
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Here is a nice "Quick Guide" to circuit breakers/fuses/and fuse blocks, with great pictures:
*https://bluesea.com/files/resources/reference/Quick_Guide_to_Blue_Sea_Fuses_and_Circuit_Breakers.pdf*

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Here is a quick read on "Choosing Circuit Protection" (-article from Blue Sea Systems)

Blue Sea Systems' engineers identify new factors to consider when selecting high amperage circuit protection.

Circuit protection devices are installed in circuits primarily to protect the wire. Choosing the correct circuit protection device and sizing it correctly for your boat is very likely more difficult than you think. To select the correct circuit protection device, the rating of the circuit protection device is matched to the rating of the wire it protects. To guide this match between wire rating and proper circuit protection rating, standards tables are available such as the American Boat and Yacht Council (ABYC) tables of amperage capacity for wire size and wire insulation rating. Table IV of ABYC E-11 for DC systems is frequently referenced, in particular, for 105°C rated wire (see Blue Sea Systems' catalog or click here). Choosing circuit protection would seem to be an easy matter-use this table to match the nominal value of a fuse or circuit breaker to the appropriate wire rating. However, it's not that simple.

When matching circuit protection to the wire it protects, two facts contribute to the complexity of this task:

Fuse Blow Point, Circuit Breaker Trip Value. The amperage at which fuses actually blow, and circuit breakers actually trip, is considerably higher than their nominal ratings. SEA, Maxi, ATO and AGC fuses, and most circuit breakers, blow or trip at about 130% of their rating. ANL fuses blow from 140% to as high as 266% of their rating. (See ANL Fuse Blow Point table below.)
Current Heating. Wire and circuit protection devices heat up dramatically when they carry 100% of their rated value for several minutes or more. At about 150% of its current-carrying rating, wire generates enough heat to melt its insulation.


ANL Fuse Blow Point
(Table below needs formatting, sorry. It has 3 columns
*Nominal Rating (Amps) Avg. Blow Point (Amps) @ 500 Sec. Blow Point (%)*
35 93 266
40 100 250
50 120 240
60 130 217
80 155 194
100 175 175
130 220 169
150 250 167
175 290 166
200 320 160
225 380 169
250 400 160
275 420 153
300 500 167
325 480 148
350 570 163
400 620 155
500 710 142
600 880 147
675 950 141
750 1050 140

The way in which circuit protection is chosen depends on whether the protection is for a short circuit¹, or for an overload².

Short Circuit Protection

If a wire feeds a predetermined load that will not change, the main concern is short circuit protection. Circuit wire is sized so that it safely carries the normal current loads for the application it serves. If there is a short, the high current in the circuit lasts for a short period of time before the fuse blows, and therefore generally does not damage the wire. Precise sizing of short circuit protection is not critical. A fuse or circuit breaker rated at an amperage value equal to the wire rating, or even up to 150% of the wire rating, is sufficient because the over-current condition lasts only a short time³. SEA, Maxi, ATO ,AGC, and ANL fuses are good choices for short circuit protection.

Overload Protection

However, if a load can increase into a sustained overload condition, approximately 110-150% of the wire rating, the wires and the protective device in the circuit may heat up. This overload condition might occur with motor loads, wiring to receptacles for plug-in appliances, or panel feeders where more than an intended number of loads can be turned on simultaneously. Selecting a fuse or circuit breaker for overload protection is more complex than choosing one for short circuit protection.

Choosing Circuit Protection for Overload Protection

In general, wire should carry current continuously at no more than 80% of its rating. Recall that the blow point or trip value of most fuses and circuit breakers (except for ANL and those based on European standards) are consistently about 130% of their nominal value. Therefore, to provide overload protection for wires, choose a circuit protection device, such as SEA, Maxi, ATO, AGC, that is rated at 80% of the recommendation in ABYC E-11 Table IV.

Furthermore, wire ratings are based on wire in open areas with good air circulation. Be even more cautious if wires are surrounded by thermal insulation such as loom, conduit or constricting structures. In these conditions, wire can carry even less current before heating up excessively. Look for more information about these effects in a future technical brief.

An Example: Choosing Suitable Circuit Protection

According to ABYC tables, 4 gauge AWG wire will safely carry 160A. Furthermore, this wire will safely tolerate 185A, approximately 115% of its rated value. Since most fuses and circuit breakers have a blow point or trip value that is 130% of their nominal rating, choose a fuse that is rated at 80% of 160A. A 125A nominal rating SEA fuse is a good choice-it has a blow point of 130% of 125A=162A.

Sizing Circuit Protection to the Load

A fuse or circuit breaker should not continuously carry more than 80% of its rating to avoid overheating of the circuit protector itself. In this example we have chosen a 125A fuse to protect the #4 gauge AWG wire. The fuse should not carry more than 100A continuously. Therefore, consider the load requirement in this circuit. If the load requirement is greater than 100A, choose a larger wire, and a larger fuse suitable for the load requirement and that will protect the wire.

Because ANL fuses behave differently than all other circuit protection devices, that is, their blow point value ranges from 140 to 266% of nominal value, the 80% rule doesn't work. It is necessary to use a different procedure to select a suitable ANL fuse. To choose a suitable ANL fuse, refer to the ANL Fuse Blow Point table above. According to the table, a 100A ANL fuse has a blow point of 175A. Therefore, a 100A ANL provides suitable protection for the 4 gauge AWG circuit in this example.

A short circuit is an overload condition in which current flows from the source and returns without circulating through the intended load. Short circuits can be caused by mis-connection or by insulation failure. They can result in extremely high currents, limited only by the source capacity and resistance of the wiring.
Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. (source: National Electrical Code Handbook, 2002)
ABYC 11.12.1.4. Non-motor Loads - The rating of overcurrent protection devices used to protect a load other than a DC motor shall not exceed 150 percent of the ampacity of its supply conductor. (See Table IV.)


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## HOUSE

(I will edit the links later, I ran out of time after work).

:!:


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## PSG-1

Excellent post! Lots of good info.


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## bcbouy

nice job,now everybody get to ripping yours out and doing it right! :LOL2:


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## Gramps50

NIce How-To a lot of usefull information, thanks


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## FuzzyGrub

Allot of good info, and appreciate the effort to post it since you have spent allot of time wading through all of it as a newbie, and can post from that prospective. Unlike many aspects to our projects, where how something is done, can be very subjective or have little or no impact, with electrical wiring, SAFETY has priority. Please be careful with using your project as a good example. "and yes, there probably is a better way to do what I did, but it works!: " Works, better, and SAFE, are not the same. Electrical standards were created over a long period of time from inspecting ashes from electrical wiring that worked.  

OK, off the soapbox. It may be only an omission, but it is very key to safe wiring. In your example, you did not mention purchasing, installing, or show a circuit breaker or fuse to your panel. Just like your trolling motor, it is required. It looks like you wired it with 6ga which while probably oversized, that is not a safety issue. In that case, you don't want to "fuse to the wire size". Most panels are only rated at 30-35A, so you don't want to exceed panel rating. A panel meltdown is not much better than a wire meltdown, but a litttle less likely to happen. 

There are other cases in your example that may have a similiar issue, but the safety risk is probably much less. While 14ga is a good wire to use for most loads, connecting it to thinner wired devices, such as FF and LED lights, means fusing to the smallest wire size or individually inline fusing the device. General rules are good, but there are times they don't apply.

PS: While I feel I know this subject fairly well, I don't regularly design such things, so do not consider myself an expert in this. There are plenty of aspects that I may be missing as well.


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## Bob Landry

He does in fact need a circuit breaker going to the panel. While the fuses/breakers on the panel will protect the wiring for the individul circuits, the wile from the battery to the panel needs to be protected as well. There is always the possibility that the jacket on the wire can chafe and short to ground, probable or likely, no... Possible, yes, and that is evidenced by the many insurance claims that have been filed for burned up boats. As far as the size of the circuit breaker feeding the panel... I always use large wire to eliminate the issue of voltage drop, but the C/B needs to be sized in accordance with the total load that is going to be going through the panel, Unfortunately, most people don't bother to look at the manuals for all of their equipment and figure out the total amp draw, also evidenced by the many insurance claims that have been filed for burned up boats.
On sizing wire and circuit breakers, two things are important. The wire needs to handle the normal operating current for the device and the circuit breaker needs to be sized to protect the wire feeding it while allowing operating amperage to go to the device. You can use as large a wire as you want, just don't over-fuse it. Also, ABYC requires that the protective device, fuse or circuit breaker be within 7" of the power source if the wire is not enclosed in a protective jacket.


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## spes

> ABYC requires that the protective device, fuse or circuit breaker be within 7" of the power source if the wire is not enclosed in a protective jacket.



In the case of fusing the power source to the panel... does the above statement mean the fuse is within 7" of the panel or 7" of the battery?


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## FuzzyGrub

spes said:


> ABYC requires that the protective device, fuse or circuit breaker be within 7" of the power source if the wire is not enclosed in a protective jacket.
> 
> 
> 
> 
> In the case of fusing the power source to the panel... does the above statement mean the fuse is within 7" of the panel or 7" of the battery?
Click to expand...



7" of the battery. If it was the panel, it would only be protecting that last 7" from a short.


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## HOUSE

oh dear...I totally overlooked the circuit breaker from the battery to the switch! thanks guys. I would have had 10 feet of potential red-hot wire running down the middle of my boat 

My total amp load on that panel is only running about 10amps (3 lights, 1 Fishfinder), but since I might add a rear trolling motor down the road, can I put another 50amp Circuit breaker on it now? I'm a little uneducated as to what happens when you have too large of a fuse/circuit breaker running to something. aka, what are the risks running my panel on a 50amp c/b before I install the second trolling motor?

(I'll update my guide as soon as I understand this one...)

thanks again!


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## FuzzyGrub

HOUSE said:


> oh dear...I totally overlooked the circuit breaker from the battery to the switch! thanks guys. I would have had 10 feet of potential red-hot wire running down the middle of my boat
> 
> My total amp load on that panel is only running about 10amps (3 lights, 1 Fishfinder), but since I might add a rear trolling motor down the road, can I put another 50amp Circuit breaker on it now? I'm a little uneducated as to what happens when you have too large of a fuse/circuit breaker running to something. aka, what are the risks running my panel on a 50amp c/b before I install the second trolling motor?
> 
> (I'll update my guide as soon as I understand this one...)
> 
> thanks again!



It is not a good idea to run a trolling motor off a circuit panel. Run it on its own circuit, with wires back to the battery. Most circuit panels, are not rated to handle that amount of current. I doubt the one you have is, but check it. Most are rated at 30-35A total, or 30A max per circuit.


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## HOUSE

FuzzyGrub said:


> It is not a good idea to run a trolling motor off a circuit panel. Run it on its own circuit, with wires back to the battery. Most circuit panels, are not rated to handle that amount of current. I doubt the one you have is, but check it. Most are rated at 30-35A total, or 30A max per circuit.



Doh! silly oversight... I should have caught that. I can run an extra #6gauge wire to the back pretty easily later on. My switch is only rated for 15amps, but my devices are only drawing about 5-10amps (Bow light: 1amp?, Stern light: 1amp?, LED light: 1amp, Fishfinder: 225mA (=.225amps, right?), & a possible bilge pump: unknown amps until I buy it, but I'm guessing 1-5amps). 

Is there going to be an issue if I put a 15amp circuit breaker on the switch and then have individual 2-5amp fuses for each device built into the switch? ...I guess I don't understand what happens if you "over" protect something with too much of a fuse. If something shorted out, it would theoretically blow the 2amp device fuse first and then possibly trip the 15amp circuit breaker, right? So no harm having both?

-House (I'm starting to have that "Chinese Algebra headache" again, grrr).


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## Bob Landry

Don't confuse switch panels with circuit breaker panels. Both are out there and serve their own purpose. A C/B panel can be used to source power to about anything, AC or DC, as the slots can be pipulated with almost any capacity breaker. Switch panels are intended to power low voltage, low current draw loads like lights, stereos, etc. Switches that you find in these panels probably aren't going to handle more that 15A.


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## HOUSE

I get that part, I think I meant to say "fuse" instead of "circuit breaker" off the battery to the switch box. Rephrased: If I protect the main wire going to the switch with a 15amp "fuse", and my switch already includes 1-5amp fuses in it, what is the concern I keep reading about of "over-protecting" everything. I keep reading not to use too high of a fuse or circuit breaker in a line. 

I think I get it... the individual fuses will protect each device while the main 15amp fuse will protect the 10ft wire running to the switch (and the switch board itself?). I'm just confused about stacking fuses inline like that, and what happens if you have too high of a fuse protecting something. For example, what would happen if I had a 10amp fuse protecting one of the 1amp LED lights... 2-9amp surges could still get through and damage the LED light?


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## FuzzyGrub

HOUSE said:


> I think I get it... the individual fuses will protect each device while the main 15amp fuse will protect the 10ft wire running to the switch (and the switch board itself?).
> 
> CORRECT
> 
> I'm just confused about stacking fuses inline like that, and what happens if you have too high of a fuse protecting something. For example, what would happen if I had a 10amp fuse protecting one of the 1amp LED lights... 2-9amp surges could still get through and damage the LED light?



Fuses and CB's are not there to protect the device. They are there to keep the wire from melting down and causeing a fire.


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## JMichael

FuzzyGrub said:


> Fuses and CB's are not there to protect the device. They are there to keep the wire from melting down and causeing a fire.


I'm going to guess that this is the perspective of an electrician and not that of an electronics technician. But even at that, if the cb's are there to protect the wires, why do you find in standard household wiring the use of 15 and 20 amp and GFI breakers all in use on 12 gauge wire?


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## FuzzyGrub

JMichael said:


> FuzzyGrub said:
> 
> 
> 
> Fuses and CB's are not there to protect the device. They are there to keep the wire from melting down and causeing a fire.
> 
> 
> 
> I'm going to guess that this is the perspective of an electrician and not that of an electronics technician. But even at that, if the cb's are there to protect the wires, why do you find in standard household wiring the use of 15 and 20 amp and GFI breakers all in use on 12 gauge wire?
Click to expand...


We are talking about fuses in a panel, so it is more like an electrician. If there is a fuse in the device, then it may be there to help save the device, but usually to prevent fire in the device. Fuses or CB's are generally too slow to save device. An over-current in the device, probably means something has already failed. 

GFI are to protect you, when using AC equipment in a wet environment. Not the device plugged into the outlet. While I haven't heard of using DC GFI's, if they were used in the posters panel, as soon as the LED lights are turned on, it would trip.


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## FuzzyGrub

House,

Here are some fuse sizes I'm using for now:

- Anchor Light: 2A (1.5A draw)
- Nav Light: 2A (1.5A draw)
- LED Rope Lighting 1 watt per ft, 19.8ft/12 = (1.65A draw), 2A fuse
- Bilge Pump: Rule 500gph, 2.5A (1.9A draw)
- Aux 1: 5A
- Aux 2: 5A
- FF: 1A (600mA draw)

The nav and anchor light is just what I found for average incadeciant type. Anchor will drop if I go with LED.


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## HOUSE

Fuzzy, thanks a lot for sharing those numbers. It helped me visualize things with my build seeing the amps and the draw.

I have to buy a fuse block for the 15 amp fuse I'm going to use to protect the wire to my switch. Ironically, I'm using a fuse that actually came installed on the switch itself  I think it's just a standard 1/2" or 1" AUG fuse, I'm going to check locally tonight for one. An Autozone type store should have that and some 2amp fuses to put into the switch, wouldn't they?


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## FuzzyGrub

HOUSE said:


> Fuzzy, thanks a lot for sharing those numbers. It helped me visualize things with my build seeing the amps and the draw.
> 
> I have to buy a fuse block for the 15 amp fuse I'm going to use to protect the wire to my switch. Ironically, I'm using a fuse that actually came installed on the switch itself  I think it's just a standard 1/2" or 1" AUG fuse, I'm going to check locally tonight for one. An Autozone type store should have that and some 2amp fuses to put into the switch, wouldn't they?



I haven't purchased those items there, but would think they have them.


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## whistler

I had to look too hard to find this post this morning as I needed to review some data for todays project. So actually this is just a shameless bump :wink: ........This post has got a lot of good reference material & links in one spot. I (just like today) find myself going back to it quiet often. "House" you are to be commended for the work you did compiling this material. In my opinion it would make a great sticky. Thanks


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## Mojo^

Good Lord, why isn't this a sticky? A ton on good information all in one place. Many thanks to those that put forth the time and effort to put together such an informative post.


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## tynimiller

This or another one for wiring a boat "for dummies" needs to be a sticky. Honestly this is the one thing that is keeping me from truly building my modification on our semi-v...just not confident in the entire wiring set up.


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## TMax27

Sticky?


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## simbelle

Just found this post. Thank you very much; It looks like what you have laid out is basically what I'm planing for my boat. I have done a little wiring on a previous boat I owned , but it was bigger and brand new and had most everything wired to a factory panel, ( I just installed a 36 volt TM and some odds and ends), I will be refering back to this as the panels and the busbars confuse me, Thanks for the guide. =D>


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## SMOOTHboar

Thank you for taking time to write this up. I am not there yet. But it's nice to start thinking ahead.


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## yareelohim

Thanks for the how-to


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## Kochy

Just thought I would bump this seeing as there is some good information, and I'm planning on redoing my electrical on my boat.


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