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Anthony, ASE Certified Technician
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Experience:  ASE Master Automobile Technician with over 20 years exp.
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Need advice wiring a couple 12 volt accessories into a work

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Need advice wiring a couple 12 volt accessories into a work truck.


- 12 Volt portable chemical pump used for pumping chemical out of 55 gallon drums. Max amp draw is labeled at 27 amps.

- 12 volt centrifuge. Apparatus used for spinning volumetric test tubes. It also has a switch for a heater on it. The tag on this thing states the Max amp draw is 9/32. I'm guessing one value is for the built in heater (controlled by a on/off switch on the side of the centrifuge) and the other is for the centrifuge itself. The centrifuge has a dial on the front of it to control the RPM's it spins at. All the way to the left its off. All the way to the right, max speed.

I plan to wire the centrifuge into the tool box I have in the bed of the truck, with TWO switches in the cab of the truck. One to turn on the heater for the centrifuge and the other to give power to the centrifuge itself. My questions regarding this are what guage power/ground cable should I use? How about amperage ratings of the switches?

I would like to use a quick connect system similar to trolling motors for the chemical pump. I've seen them for sale anywhere from 16 gauge down to 8 gauge. Its basically a waterproof male/female two prong quick connect. The female side would mount somewhere in the bed of the truck. The male end would be connected to a 6 foot cord coming off the pump. This would provide me the ability to move the pump around in the bed, and still be connected. Then be able to disconnect when I'm done and put it away. What gauge wire should I be using to wire the female end of this quick connect to the box of the truck?

How about inline fuses? Where should they be located? Amperage?
Hello! Welcome to justanswer!

The wire size for you is 8 gauge for the power and ground wires. And the Fuse Size is 40 Amps. Its best to use two maxi fuse in line holders with two 40 amp fuses hooked directly to your battery. As for the switches, use high amp pull switches rated at 30 amps or above.
Customer: replied 3 years ago.

since these switches will be going into a brand new 2013 dodge ram, which my company owns, I would like them to at least look decent. Are there high amp rocker switches out there? Or do you know of an alternative to a pull switch?


I'm visualizing pull switches being an eye sore mounted in the cab of this truck.

NAPA Auto Parts sells a high amp toggle switch. That should work fine. Get all of the supplies from them as they are a high grade part.
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Customer: replied 3 years ago.

I was able to find pretty much everything I needed between NAPA and O'Reilly's. One more question:


I cannot find any 8 gauge insulated connectors for the back of the switch though. Biggest I could find were 10-12 gauge connectors. Is it OK to drop down to a smaller gauge wire behind the switch? Or should I keep looking to stay with 8 gauge wire throughout this system?

Its ok to drop down to 12 at the connections to ease installation. As long as the long runs are in 8, you will be fine.
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Customer: replied 3 years ago.

Perfect. Thanks again for your help on this. You've been most helpful!

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