Adding a 30 A 12V circuit

[OneOleMan]

Now that I've recovered from my "Self inflicted wound" I'm off to another electrical project and would like some advice from experts.

I want to add a 30 A 12V circuit for one of my Icom ham radios and according to the WFCO owner’s manual circuits #’s 10 and 11 can be used.
“DC Fuses (12 Volts)
- Eleven 12 Volt circuits (including two circuits for slideouts)
- Maximum of 30 Amp fuse for DC circuits 10 and 11 (all others max. 20 A)
- Reverse battery protection fuses; replace with
ATC “Littelfuse ” Type 257 fuse”

Now I need to clarify the proper wiring; the positive would go to either 12V circuit # 10 or 11 and the negative to the upper buss bar on the left. I’ll be using 14 gauge wire terminating a short run from the converter with an Anderson Power Pole. This is going to be an experiment to see if the batteries and solar system are able to handle the load. If all is good then I'll decide on a location for a permanent plug.

Another option would be to tap into the incoming battery feeds. The power line to the radios has inline 30 A fuses so I’d still be protected but somehow I feel better with 2 forms of protection.

[bdornbush]

For 30 Amp circuits, the wire size should be 10 gauge. 14 gauge wire is rated for 15 amps.

[Jubal]

Amps and Wire Gauge - 12V Circuit
14 and 10 gauge AWG are both too small.
The correct wiring gauge would dependent on the length of the wire in the circuit.
The circuit should be fused at the distribution panel or you may not be able to escape the reality of a shorted circuit. A shorted fuse saved you before.

[OneOleMan]

Originally Posted by bdornbush

For 30 Amp circuits, the wire size should be 10 gauge. 14 gauge wire is rated for 15 amps.

Good catch, bdornbush, I know better, really I do. It's a good thing the wire I'd be using is the same that comes with the radios and it's 10 feet long - more than enough for what I need.

I was thinking about 2 projects at the same time, one of them actually using 14 gauge.

[Mike Lewis]

I need to do the same thing for my Icom IC-7000. I hadn't considered going through the WFCO panel, since the Icom manual recommends connecting directly to the vehicle battery. My radio draws 22 amps when transmitting, so I have to do this right.

I guess you could connect directly to the battery feed and use two 30A fuses in series for extra protection.

[alanmalk]

Originally Posted by Mike Lewis

I need to do the same thing for my Icom IC-7000. I hadn't considered going through the WFCO panel, since the Icom manual recommends connecting directly to the vehicle battery.

The shortest possible run of DC wire has another advantage besides minimal voltage drop: It will minimize pickup of the transmitted RF. I would consider a connection at the panel to be subject to multiple pickup paths for RF, so as Icom recommends - direct to the battery, if possible.

--
Alan

[LeonardS]

Originally Posted by Mike Lewis

I guess you could connect directly to the battery feed and use two 30A fuses in series for extra protection.

Is the radio load that inductive that you need to series the fuses?

[OneOleMan]

Originally Posted by Mike Lewis

I need to do the same thing for my Icom IC-7000. I hadn't considered going through the WFCO panel, since the Icom manual recommends connecting directly to the vehicle battery. My radio draws 22 amps when transmitting, so I have to do this right.

I guess you could connect directly to the battery feed and use two 30A fuses in series for extra protection.

The power cable that came with both my IC-746PRO and IC-756PROIII have a 30 A inline fuses for both sides, red and black.

[OneOleMan]

Originally Posted by alanmalk

The shortest possible run of DC wire has another advantage besides minimal voltage drop: It will minimize pickup of the transmitted RF. I would consider a connection at the panel to be subject to multiple pickup paths for RF, so as Icom recommends - direct to the battery, if possible.

--
Alan

Alan, thanks for reminding me about RF. Between you and Mike jogging my poor memory I'm going to do the battery hook up.

I really getting anxious to give this a try before getting out to the boonies.

[Mike Lewis]

Yeah, I think it has a fuse. I have only used the radio a few times, and those were at home via a plug-in power supply. But it's meant for vehicle use and I intend to become a more active ham. The skill could come in very handy when boondocking. Well, with a big battery and solar panels, that is...

[gbaglo]

All this talk of fuses has me wondering what Canadians are supposed to do now that the penny has been withdrawn from circulation.

[OneOleMan]

Originally Posted by gbaglo

All this talk of fuses has me wondering what Canadians are supposed to do now that the penny has been withdrawn from circulation.

[jamman]

Originally Posted by OneOleMan

...

Now I need to clarify the proper wiring; the positive would go to either 12V circuit # 10 or 11 and the negative to the upper buss bar on the left....

I strongly recommend you do NOT use the negative you have indicated - that is for 110V wiring. Mixing 12V and 110V wiring is NOT a good idea.

[Mike Lewis]

Originally Posted by LeonardS

Is the radio load that inductive that you need to series the fuses?

I don't know; I just don't have the knowledge or experience with the radio. I'm hoping someone else goes first on this project and I can learn from them.

[Ron in BC]

My vote would be to not use the panel because of the multiple connections already in the circuit. On my trailer at least, ETI wires the battery ground to the exposed frame; then about 18" away connects the ground from the panel. My view is that exposed connections like that will likely develop corrosion and a higher resistance.

So for a high draw load like yours I'd tend to wire it directly to the battery.

Ron

[OneOleMan]

Originally Posted by jamman

I strongly recommend you do NOT use the negative you have indicated - that is for 110V wiring. Mixing 12V and 110V wiring is NOT a good idea.

Thanks for that info, Doug, this is definitely a learning process for me and now I know I should go directly to the batteries. Now gotta figure the attachment point for a pair of 6V batteries.

[dfandrews]

Originally Posted by Ron in BC

... On my trailer at least, ETI wires the battery ground to the exposed frame; then about 18" away connects the ground from the panel. ...Ron

Well now, THAT is very interesting. When we were at Escape Trailer Industries in November, among the questions I asked was if the ground was a wired ground or through the frame.
On the noon factory tour, Crystal rounded up one of the electrical assemblers, who told me it was a wired ground.
I am most concerned with high amp loads such as the trailer brakes, but electronic devices also love good grounding.
When I go to pick up my 17, I'll have to remember to take some extra wire; got to have good grounding. Chassis grounding, with the associated potential (yeah, pun intended) for corrosion, is not the best.

[tractors1]

I use this for wire sizing:

Voltage Drop Calculator

[Ron in BC]

Originally Posted by dfandrews

I asked was if the ground was a wired ground or through the frame.
On the noon factory tour, Crystal rounded up one of the electrical assemblers, who told me it was a wired ground.
I am most concerned with high amp loads such as the trailer brakes, but electronic devices also love good grounding.

Well, it is a wired ground, just not quite a fully wired ground.

This photo shows the set-up. Battery ground to frame. The ground to the panel continues on the other side held by the bolt protruding on the left. This photo was taken when it was less than 2 weeks old. You can see rust forming already and I know that when copper wire strands are exposed like that corrosion develops not only at the end but for quite a ways along the wire. It's difficult enough to keep batteries fully charged. Seems a shame to waste energy with degrading wiring.

I left the factory ones in place but paralleled them with a continuous cable when I installed my battery switch and second battery.

Ron

[dfandrews]

Originally Posted by Ron in BC

...This photo shows the set-up. Battery ground to frame. ...
I left the factory ones in place but paralleled them with a continuous cable when I installed my battery switch and second battery.

Ron

Ron,
Thanks for the info and photo. The paralleled continuous ground cable sound like the operative plan.