What gauge wire

[redneckpunk]

Working on a complete build of a 14ft aluminum with side console and have a quick question about wire gauge. Here's my plan, correct me where you think I might be wrong. Battery will be stern mount. Negative fuse block at stern. 12 gauge wire from battery to console mounted fuse block. 16 gauge wire from fuse block to fused switch panel on dash. 16 gauge from switches to accessories (lights, bilge, lighter, radio, etc).

So here's a couple questions. With a fuse block at the helm, do I need a separate negative bus block at helm or will negative on the fuse block work? Are my gauges of wire correct?

 

[Scott Danforth]

I would run 10 gauge or larger. 16 gauge is good for 10 amps, 10 gauge is good for up to 30 amps

 

[Baylinerchuck]

No Title

Totally agree with Scott on running at least 10 awg for your helm circuits. Ground is ground so the ground stud on the fuse block is fine as long as there is enough room. A buss block may be easier to wire and organize.

 

[Grandad]

Working on a complete build of a 14ft aluminum with side console and have a quick question about wire gauge. Here's my plan, correct me where you think I might be wrong. Battery will be stern mount. Negative fuse block at stern. 12 gauge wire from battery to console mounted fuse block. 16 gauge wire from fuse block to fused switch panel on dash. 16 gauge from switches to accessories (lights, bilge, lighter, radio, etc).

So here's a couple questions. With a fuse block at the helm, do I need a separate negative bus block at helm or will negative on the fuse block work? Are my gauges of wire correct?

Your #12 AWG may be large enough, depending upon what your lighter outlet is used to power. Part of the wire size consideration is "voltage drop" which occurs as current load increases. Wire length also adds resistance contributing to voltage drop, but your boat is relatively small, so the wire lengths will have a lesser effect than on a larger boat. The actual "ampacity" of a wire is based on the heating effect of current flow, so that also considers the length of time that an appliance is used. A large horn for instance can draw a significant amount of current, but the duration is short, so there's likely no danger of melting a wire. If the wire feeding the horn is small though, you may notice a reduced sound volume or interference in electronic equipment fed from the same main feed due to voltage drop. - Grandad

 

[Silvertip]

You refer to a "negative fuse block" at the stern. You do not install a fuse block in the negative line of any circuit. There is need for only one negative connection at the stern and that goes directly to the negative terminal of the battery. If the helm fuse block does not have a ground bus terminal on it, then that's where you install a negative bus. All of the ground leads from the accessories connect there. A #12 or #10 gauge wire runs from that ground bus back to the battery. Likewise, a #10 or #12 (minimum) POSITIVE lead runs from the battery positive post, through a breaker or fuse at the battery, to the INPUT to your fuse block at the helm. 16 gauge wire can be used for all low current draw branch circuits.

 

[fishrdan]

Buy one of these and mount it in the helm, you could possibly get away with the 6 circuit model.. Run 10ga (or 12ga if light loads) from the battery to the - and + posts on the fuse block, then 16ga from the fuse block out to the accessories or switches. Use the integrated negative buss on the fuse block, it's not needed at the stern on such a small boat.

If you are running a trolling motor, it will need completely independent wiring, and should also be on it's own battery(s).

I used one of these fuse/switch panels in my 14'er, along with a negative buss bar. It's much simpler than using a fuse block and separate switches, depends on the layout of your helm though.

 

[Fed]

It's good practice (it may even be a rule) to have all conductors of the same circuit originate at the same location.
You don't want a situation where the Positive for the bilge pump comes from the helm but the Negative comes from the battery.

I think the Blue Sea product fishrdan put up would be fine for you but depending on your requirements I'm not a fan of the switch/fuse panels because you have to cut a big hole in your boat to fit them. You need to figure out what equipment you want to install.

Switches switching switches is just horrible IMO, so far you only need 2 switches (lights & bilge) and if you lay out an area on the dash you can always add more IF you ever need them.

 

[redneckpunk]

Buy one of these and mount it in the helm, you could possibly get away with the 6 circuit model.. Run 10ga (or 12ga if light loads) from the battery to the - and + posts on the fuse block, then 16ga from the fuse block out to the accessories or switches. Use the integrated negative buss on the fuse block, it's not needed at the stern on such a small boat.

If you are running a trolling motor, it will need completely independent wiring, and should also be on it's own battery(s).

I used one of these fuse/switch panels in my 14'er, along with a negative buss bar. It's much simpler than using a fuse block and separate switches, depends on the layout of your helm though.

Using that at the helm was my plan. I guess while trying to explain things I confused a few people an duses the wrong terminology at one point. So let me see if i can clarify and re-ask. Will i be alright running #10-12 from the battery to the above mentioned fuse junction at the helm? And from there, will I be alright running #16 to the switch panel on the dash which is also fused. And will the #16 be good to run from the switches to lights, bilge, etc?

My reason for wanting the negative bar on the transom is to eliminate running the negative wires from aft mounted accessories all the way back to the helm. For example, stern light, bilge pump, interior lights, livewell pump, or anything else that may be located at or near the stern. I can run the negative wires 10ft back to the helm or a maximum of 2ft to the bar if properly located. Is this thinking off base?

 

[Grandad]

It's good practice (it may even be a rule) to have all conductors of the same circuit originate at the same location.
You don't want a situation where the Positive for the bilge pump comes from the helm but the Negative comes from the battery.

Not sure just what you're concerned with here, Fed. If this was AC wiring such as in a building, this would be important and you're right, it actually is a rule in both the NEC and CSA codes that require that magnetic fields be cancelled by running the hot and neutral wires together. It becomes very important where large AC single conductor (free air rated) cabling is installed because strong magnetic fields can develop and cause the formation of "eddy currents" and sheath currents that raise the temperature of the cable and fittings. I don't think there are any such requirements in the ABYC code. I wouldn't want to run extra distance to get the negative from the same panel as the fuse or breaker. In some cases, such as when a bilge pump is fused or switched near the helm, there should be no detrimental effect of picking up the negative from a post or terminal strip near the battery. Running the negative side electron flow forward and then rearward back to the battery adds resistance and more voltage drop. - Grandad

 

[bruceb58]

Make sure the 10 gauge wire you run from the battery to your helm fuse box is fused/breakered at the battery.

 

[Fed]

No concerns with function Grandad I simply think it's a better way of doing it.
I should mention I just moved my smart phone because it wasn't sitting parallel to the edge of the desk, it was crooked by a whopping 1/4", does that explain things?

 

[bruceb58]

Not necessary to run grounds back to the engine compartment from the helm mounted fuse box. You already have the ignition power running back to the engine compartment form the ignition switch. I can guarantee you that none of the engine manufacturers run a ground back with it.

From the factory, my Wellcraft's ground for the blower and the bilge pump come off a bus bar located back at the engine.

 

[Fed]

Sometimes manufacturers do stuff to save a few cents, how are the Positives wired Bruce?

 

[fishrdan]

Sounds good. No problem having a negative buss bar at the stern, I have one for all the accessories back there like you mentioned. Eliminates all the grounds going back to the helm.

 

[bruceb58]

Sometimes manufacturers do stuff to save a few cents, how are the Positives wired Bruce?

As you would expect they would be....go through a fuse on the fuse panel, to a switch and then to a load.

Why would you run a negative wire all the way to the helm and then run all the way back to a load? You are only adding unnecessary voltage drop.

It's a perfectly acceptable practice to not run a separate ground along with the positive side going to a load. It s done all the time on both autos and boats.

 

[Fed]

Why would you run a negative wire all the way to the helm and then run all the way back to a load?

Because I see the Wellcraft alternative as being lazy or stingy or both.

Why wouldn't Wellcraft switch & fuse the rear equipment back at the battery and save even more money?
I'll tell you why, people would say Wellcraft wiring is rubbish but with the short cut grounds... well, what the people don't know won't hurt them.

In my mind it's like using trailer frames as a ground conductor, do they do it, Yep, does it work, Yep, is there a better way...Yep.

As usual it looks like we'll have to agree to disagree, it's all good but I have to say I'm surprised at your stance on this one.

 

[redneckpunk]

Thank you all for the confirmation that what I'm doing is going to work.

 

[bruceb58]

Why wouldn't Wellcraft switch & fuse the rear equipment back at the battery and save even more money?

Because the fuse needs to be near the switch and the switch has to be at the helm. Anymore questions?

LOL...I am not surprised at your stance looking back at how you think multimeters work.

 

[Fed]

Who says the switch has to be at the helm?

Because I choose not to bother discussing stuff with you don't ever get the idea you're right, it only means you have bored me into submission.

 

[bruceb58]

Because I choose not to bother discussing stuff with you don't ever get the idea you're right, it only means you have bored me into submission.

LOL....your explanations of things always surprise me. Never boring what you come up with.