Wiring Questions

[Andy in NY]

Okay, i am ready to tackle some wiring issues (nothing major). so far, i have removed the switches for accesories and the fuse block, and am going to replace with a new 6 gang fuse/switch panel. the wiring that comes up to the helm to power stuff is seperate from the main harness, but has a few splices in it, and want to run new 12v power and ground from the battery.

what gauge should i run from the battery to the panel? should the ground be the same size as the power?

that TYPE of wire should i use? can i use rehular automotive type from an auto parts store?

should i put the anchor lights and nav lights on seperate switches?

can i combine the radio and depth finder on the same switch?

can i run speaker wire in the same loom as power and not get interferience? can i run the wire for the transducer in the same loom as power?

i think thats it for now... to get me started.

 

[Chris1956]

Re: Wiring Questions

Ground and power wires should be the same gauge. Wire size is based upon amperage of all the accessories. A 15 Amp circuit is usually a 14 AWG. Marine wire is the best, and is essential if you boat in saltwater.

You can power raio and FF off same switch. Navigation and anchor lights are usually powered off a single SPDT switch. The speaker wires should not pick up interference from the power wires, unless you have a motor with brushes or some other electrically noisy device. (Think about running the vacuum while watching TV). Ditto for the transducer.

 

[Andy in NY]

Re: Wiring Questions



this is the panel i am using... and specs say it is rated for 15A, so 14AWG it is!

i know alot about AC wiring, but this is my first time tackeling any DC stuff...


one more question about anchor lights. are does the polarity matter with them? the current light has 2 black wires coming out of it.

 

[Mischief Managed]

Re: Wiring Questions

I would use more than 14AWG (which by the way is good for 35 amps if its marine wire due to the higher temperature insulation). You should not be terribly concerned with the total current, but voltage drop is an issue, (especially with electronics). A larger wire will have less voltage drop. Since the boat is an insulator and you'll need power and ground wires, the "ground" wire length needs to be included in the voltage drop calculation. If the total length of the two wires is 20 feet, and you are limiting the circuit to 15 amps, 10AWG wire would give you adequate performance (3% or less voltage drop). Increase the length to 25 or 30 feet and 8 AWG is better.

There's no polarity on lights unless you have LED "bulbs".

 

[steelespike]

Re: Wiring Questions

You will get much better quicker response over in the eletrics/electronocs section.Supply and ground should be same size.10 or 12 gauge.marine grade wire.12 is rated for 20 amps,10 I think is 30amp.Items like bilge blowers and pumps you should run their ground directly to the battery or their own ground circuit.There are 2 position switches that could operate nav. or anchor lights.
I believe the depth finder should be by itself so it has clean power.
Not sure why you would put a radio on a switch; if you mean communications it should be by itself.I would run speakers and transducer seperately by themselves.You may get more specific info in the electrics section.

 

[steelespike]

Re: Wiring Questions

I would use more than 14AWG (which by the way is good for 35 amps if its marine wire due to the higher temperature insulation). You should not be terribly concerned with the total current, but voltage drop is an issue, (especially with electronics). A larger wire will have less voltage drop. Since the boat is an insulator and you'll need power and ground wires, the "ground" wire length needs to be included in the voltage drop calculation. If the total length of the two wires is 20 feet, and you are limiting the circuit to 15 amps, 10AWG wire would give you adequate performance (3% or less voltage drop). Increase the length to 25 or 30 feet and 8 AWG is better.

There's no polarity on lights unless you have LED "bulbs".

Boy I find it hard to believe you can run 35 amps through any kind of 14 gauge wire.Especially if your running any kind of distance over a few inches.
and if put into a loom or run there is no place for the heat to go and other materials my not handle the heat.14 gauge terminals are not designed to handle that kind of current.
If the light uses the socket as part if the sircuit the positive wire should go to the center contact not the socket.I believe most marine sockets use a twin contact socket/bulb.

 

[Andy in NY]

Re: Wiring Questions

You will get much better quicker response over in the eletrics/electronocs section.Supply and ground should be same size.10 or 12 gauge.marine grade wire.12 is rated for 20 amps,10 I think is 30amp.Items like bilge blowers and pumps you should run their ground directly to the battery or their own ground circuit.There are 2 position switches that could operate nav. or anchor lights.
I believe the depth finder should be by itself so it has clean power.
Not sure why you would put a radio on a switch; if you mean communications it should be by itself.I would run speakers and transducer seperately by themselves.You may get more specific info in the electrics section.

the radio will be on a switch as to not have to push the button on the radio itself... its easier to forget to turn off that way. flip all the switched off and done.


this may sound crazy, but could i use NM cable for this? i have a bunch of 12-2 NM solid copper wire sitting around... is it possible to use it?

 

[Silvertip]

Re: Wiring Questions

If you are running +12V and ground wires directly from the battery, I suggest you include a MASTER On/Off switch on the panel so you can kill the panel when not in use. If you check the very top post on the "Electrical Forum" you'll find a generic wiring diagram that includes that switch. The anchor and nav lights can run from an inexpensive single pole on-off-on switch but a diode needs to be added as shown below. And just so you know, DC wire ampacity is very different than AC so I've included a chart for that as well. Also, why are you chosing to run a separate switch for a fish finder and radio since it uses up one of your switches and both devices have On-Off switches on them. The Master switch would do that job for everything. Save the switches for devices that don't have one. Lastly, if you do run two devices from one switch, make sure you don't fuse those circuits so high that should a short in either device wiring fail to blow the fuse as the ampacity of the device wire may be less than the fuse rating.

 

[Andy in NY]

Re: Wiring Questions

I would use more than 14AWG (which by the way is good for 35 amps if its marine wire due to the higher temperature insulation). You should not be terribly concerned with the total current, but voltage drop is an issue, (especially with electronics). A larger wire will have less voltage drop. Since the boat is an insulator and you'll need power and ground wires, the "ground" wire length needs to be included in the voltage drop calculation. If the total length of the two wires is 20 feet, and you are limiting the circuit to 15 amps, 10AWG wire would give you adequate performance (3% or less voltage drop). Increase the length to 25 or 30 feet and 8 AWG is better.

There's no polarity on lights unless you have LED "bulbs".

well, it is only a 14' boat, and it is only about 5 feet from the battery to the switch panel. i would say the longest run of wire at all will be 5 feet. i dont think i should have any problems with voltage drop at that distance. i mentioned earlier that i work alot with AC, and you really dont have to worry about voltage drop there till you go over 50'

should i seriously be worried about voltage drop over a span of 5-10'???

 

[45Auto]

Re: Wiring Questions

As long as you run the recommended wire sizes you won't have any problem with voltage drop with the loads you're putting on it, and at the size your boat is.

Not sure how the solid copper stuff would work. Auto, aircraft and marine wire is stranded so it resists breaking from vibration. Marine wire is also 100% tinned to protect the copper from corrosion. You've probably seen those corroded black copper ends on wire that don't conduct and solder won't stick to. I've seen whole lengths of pure copper wire on boats that have corroded and won't conduct at all.

If you intend to keep the boat I would personally use marine wire. The other stuff would probably work fine for a few years then you'll be out in the lake trying to get things to work after that!

Oh yeah, been meaning to ask about your signature! Should I get Donald Trump to sell his 400 foot yacht and buy a couple of broken down rowboats so he has MORE toys (2 boats instead of 1) when he dies? Why doesn't the "quality" of the toys count towards who wins at the end?

 

[tashasdaddy]

Re: Wiring Questions

check this out. i prefer a single main switch, that was everything is off.

http://forums.iboats.com/showthread.php?t=186986

 

[Mischief Managed]

Re: Wiring Questions

well, it is only a 14' boat, and it is only about 5 feet from the battery to the switch panel. i would say the longest run of wire at all will be 5 feet. i dont think i should have any problems with voltage drop at that distance. i mentioned earlier that i work alot with AC, and you really dont have to worry about voltage drop there till you go over 50'

should i seriously be worried about voltage drop over a span of 5-10'???

10 feet (round trip) of 14 AWG marine wire with 15 amps will be OK.

If you work with AC, you probably work with higher voltage than 12 volts so voltage drop through the wire is not nearly as much a problem. A 1.2 volt drop on 120 volts is only 1%. With only 12 volts available its a 10% drop and that's bad.

 

[Andy in NY]

Re: Wiring Questions

10 feet (round trip) of 14 AWG marine wire with 15 amps will be OK.

If you work with AC, you probably work with higher voltage than 12 volts so voltage drop through the wire is not nearly as much a problem. A 1.2 volt drop on 120 volts is only 1%. With only 12 volts available its a 10% drop and that's bad.

that makes sense with the voltage drop issue.

i plan to totally gut and overhaul the boat in a few years and make it into a CC, so i think for now i will save a few bucks and go with regular automotive type.

now when it comes to wire sizes for the things i am wiring, i have to match the size from the unit, right? say the radio has a 12awg from the harness.... u should use 12 back to the panel? and the led lights have 16, so 16 back to the panel?

what about the nav lights where i dont know the size of them?

 

[Mischief Managed]

Re: Wiring Questions

Boy I find it hard to believe you can run 35 amps through any kind of 14 gauge wire.Especially if your running any kind of distance over a few inches.
and if put into a loom or run there is no place for the heat to go and other materials my not handle the heat.14 gauge terminals are not designed to handle that kind of current.

35 amps is the limit, only if the marine 14 AWG wire is used in a non-engine space (it would be 15% less there) and if it's not bundled. If three conductors are bundled, the capacity drops 30%. If 4-6 are bundled, it drops 40%, if 7-24 are bundled it drops 50%.

 

[Andy in NY]

Re: Wiring Questions

okay, looks like this is my plan:

10AWG from the battery to the switch panel (with an inline master fuse)
12AWG to the stereo (the harness off the radio is 12, so i will match that)
the depthfinder has a wire coming out of it for power, so i will hook that using that wire
led mood lights recomend 16awg, as they have a small lead off coming off them
i am going to replace the anchor light with a new one, so i will determine then what to wire it with... and the nav lights have a lead off them so i will use that to hook right to the panel.



one more question, can i hook the nav and anchor lights together on a STSP switch and just turn them both on and off at the same time? or do they HAVE to be seperate?

 

[Silvertip]

Re: Wiring Questions

Power and ground wires should be the same gauge. There is nothing on your boat that requires 12 gauge wire or even 14 gauge for that matter. Nearly everything can be served nicely with 16 gauge (except for a trolling motor or high current draw device of course).

 

[Andy in NY]

Re: Wiring Questions

Power and ground wires should be the same gauge. There is nothing on your boat that requires 12 gauge wire or even 14 gauge for that matter. Nearly everything can be served nicely with 16 gauge (except for a trolling motor or high current draw device of course).

aye yi yi...

so many opinions!


not that im trying to ignore your advice silvertip, but i think i am going to go with the setup i mentioned in my last post.

 

[achris]

Re: Wiring Questions

As for size of wire to each device, as long as it's not smaller, you can use anything. I would buy a roll of 12 gauge wire and use that on everything. To calculate the current drawn by a light bulb, read the wattage from the bulb and divide by 12. Nav lights are usually around the 21 watt mark, so look at slightly less than 2 amps EACH. As for speaker wires, no problem in a harness with DC. Transducer cable should be run on the other side of the boat. It has a pulse of up to 600volts in it.. Keep it away from all other wiring. DON'T use solid core (house wire) cable. In my boat I have a couple of terminal blocks, one red and the other black, that are completely separate to the engine wiring. I run anything that's not engine from those. Yes you can run both anchor and nav lights on the same switch. BUT, if your anchored at night you should only be displaying the anchor light and not the running lights.

Chris................

 

[Silvertip]

Re: Wiring Questions

Using 12 gauge wire to feed what amounts to a 3-4A circuit such as the Nav/Anchor lights is a real waste of capability. Radios, locators, GPS, bilge pumps, etc all take less than 5A. 12 ga wire will certainly work, but it is going to make a very thick bundle. Getting reasonable bend radius when daisy chaining lights, +12 and ground connections on the instruments is also going to present some issues such as not fitting two #12 wires in a spade or ring terminal.

 

[SFT2]

Re: Wiring Questions

If you do need to cross signal and power wires anywhere, make sure to do it at 90 degrees, even if you have to go out of your way to do it.

And don't put antennae under a carbon fiber enclosure. I figured that one out the hard way