59Rocket

I want to run an Aux, fuse box to run the aftermarket stereo in my 1950 Super 88.

I don't want to molest the OEM fuse box as I want to keep the car in OEM spec as much as possible.

I've run new battery cables in 0 ga.

From the + side Terminal that I have a 4ga. wire, inline fused @ 60amp. That runs to a able Splitter Distribution Block. I've run an 8ga. wire to the amp.

I'd like to run a 2nd 8ga. wire to an Toggle Switch, then to a Fuse Box. I do not want the stereo run off the Acc. circuit.

QUESTION: Do I need to put an inline fuse ahead of the Toggle switch? If so how many amps? Maybe amps?

Toggle switch tend to run from 5 -25 amp. ratings. What amp rating would you suggest?

The stereo head unit has a 10 amp. fuse. I believe power antennas are 10 amp. fuses. Those will most likey all that will be running off the aux, box for now.

MDchanic

Draw us a picture.

Seriously, you have no way of really seeing what you are doing without a proper schematic.

In the end, decisions about fuse ratings rely on one of two things:
the amount of power that the circuit can handle or the amount of power you plan to put through the circuit.

The most logical thing is to determine how much the circuit can handle safely, and fuse it just below that level.
That way, when you add things in the future, you do not need to think about changing the fuse every time.
If you are certain that a certain leg will only handle a certain amount of current, and never any more, you can fuse it just above that level.
Whatever you prefer.

There is no reason not to fuse the circuit to the fuse box (GM might have used a cheaper fusible link).

8ga wire, running in the open (and not bundled or inside of a conduit) should be able to handle about 70 Amps, so fusing it at 60A (or 50, or 40, or 30...) should be fine.

- Eric

oddball

I would recommend using the toggle switch to throw a relay for the main power feed. You can also just use ACC to throw the relay. I'm not familiar with the 50's fuse boxes, but the later ones have separate taps so you don't have to cut a wire to add a circuit.

Running main power through a toggle can be really problematic as most switches just aren't made for any usable amount of current. If you do run power through the toggle, make sure it's rated higher than the sum of the fuses. Otherwise the toggle switch could fail first, which it would do by melting and/or catching fire.

Depending on how you run it, you may not need an aux fuse box. If each item is fused and you can set up a good distribution point and not worried about the unfused runs shorting to body, then that could be a lot simpler.

Octania

Be aware that switches rated at 120V AC do NOT translate directly to 12V DC


Amps, it turns out, is not just like other amps.


Typically de-rated quite a bit for 12V DC


Sounds like you want a 25-30A fuse or fusible link.

59Rocket

Thanks for the advise/comments.

After taking a 2nd look at the circuit demands, I've rethought my plan.

I had over looked the need for a constant hot supply for the memory yellow wire to the stereo. So, on/off toggle 1st would not benefit me.

I believe I would be safe/correct in running 8ga. from the battery to supply the aux. fuse box. Then power through a 30amp fuse to the 50 amp toggle I found from an off-road/race supply to the power on the stereo head unit. The head unit has a 10 amp. fuse now.

The yellow constant will run through a 5 amp. fuse.

I believe I will be safe adding the powder antenna in the future as Eric suggest the 8 ga. supply should be able to safely supply 70 amps. I can not for see ever coming close to needing that level of power through the Aux. box.