HIgh and Low draw (amperage) circuits in parallel = EXPLOSION?

A little bit of click bait there, nothing has exploded... yet...
I have a question to which I thought I knew the answer to but you know how it is, the more you think about it the fuzzier things get... so enlighten me please if you have the knowledge...

I have 480W circuit that I am thinking about tapping into (in parallel) for a mA application. Does the high amperage running through the original circuit affect the current in the smaller circuit?
I know how parallel/series circuits work and I=VR so as long as the source can hold 12v for higher current draw, the smaller circuit(s) technically would see no difference weather it is connected to the wire that is consuming 480W or another that may only be pulling 1W correct? From theory I believe there is no problem connecting a small powered circuit parallel to a high powered one. But when I say it out loud I feel like I'm missing something, would any of the current bleed into the smaller wire? is something going to explode?
So, would connecting a tiny wire to pull 5mA to a wire carrying 100A be a bad idea, or is it ok??? why or why not?
Numbers are not real just for illustration purposes, I don't know the actual loads. Also, assume that the smaller wire is enough for the smaller load and that the total current can be handled by the big wire that feeds both circuits

 

Try it and see what happens.

 

should i get life insurance first though?

 

You'll want an inline fuse holder on the 1W circuit with a fuse sized for the smaller gauge wire. Other than that no issues.

Reason for that is a short on the 1W circuit could otherwise cause the smaller gauge wire to burn before the 480W circuit's fuse ever trips.

 

Depends if your family is going to miss you when you're gone

 

If i get good enough life insurance they probably won't....

 

The power draw is dependent on the item you are feeding. For example I always run a 10 AWG line fused for 30 amps from the battery and then break it out inside the cab. Then I run smaller gauge wires to the different items that I’m feeding. Are you tapping a DC line or a 120 VAC from the inverter.

 

Don't feel bad, my wife feels the same way.

 

DC 12V, its for the taco...

 

It depends on the load on the smaller circuit.
If the smaller circuit has a load that will be smaller than what the wire can handle, then it should be fine. Otherwise, melty wires and maybe fire everywhere.
If the larger circuit is drawing at full load of what the wire can handle, and you throw the smaller circuit on, it might blow a fuse.
I think it's best to check in with @Kens04Taco the electrical guy, since I am not licensed.

 

and a Go Pro......

 

Ah. My has an inverter as well as 12 volts. Should not be an issue. I do always fuse the smaller lines as well. Just make sure your total load doesn’t exceed the max load of the source circuit.

 

You're right I dint think of that, mine has it too but I'm just referring to battery power.

 

I mean I guess it would depend on exactly how you set it all up.. But if we assume proper splices (if you really must go that route), proper sized fusing on both leads based on your FLA, and proper sized conductors I think the next issue would be voltage drop.

Depends on what you're powering through the small 'tap' and what the big load is. From what you describe I think of a small electronic device. May or may not be sensitive to voltage drops and fluctuations as the much larger load cycles on or off etc. A dedicated power lead could be a better idea.

 

Maybe a TW live feed before you do it?

 

You should be fine, but I'd love to see a schematic.

 

definitely ...

 

Add a fuse and you should be fine. Current flows from negative to positive, so think of it this way:

The battery is the ocean. The huge positive wire that comes off of the battery is a large river. Each smaller circuit that taps off of the main circuit is a smaller river or creek that flows into the larger river. Everything is feeding into the larger "river" and into the ocean. So, by tapping into that larger circuit, unless something is wrong and you don't have a fuse or you don't exceed the larger circuit's capacity, you'll be a-ok.

 

You’ll be fine. Just fuse the circuits properly and make good connections