12v input power wire gauge

[zwiller]

Wiring up a 350W (29A) power supply from Ray to my MR16 and realized after consulting a chart I need 10 wire?!  Only going a foot.  Any thoughts?  Thanks in advance. 

[tmcteer]

You could double the wires to each terminal. Also if you are that close you can test the load at your 29amp and measure the heat from the wire with an inexpensive infrared temp gauge. I use one to tune my RC cars.
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Tom

[chrisatpsu]

which chart are you referencing? one for building construction?  there's a difference between 29A @ 12V compared to 29A @ 120VAC (348watts vs 3480watts)

If it is a building wire chart, what does it say for 2.9A?

[JonB256]

Wiring up a 350W (29A) power supply from Ray to my MR16

If you are only using 10amps from a 29amp supply, you don't need to go so heavy.

My RGB mega star, connected to an MR-16, can draw a max of 16amps, but it is the only load on a 50amp supply. I'm just using 16gauge wire. Full on power test, it didn't even get warm.

[gatorengineer]

which chart are you referencing? one for building construction?  there's a difference between 29A @ 12V compared to 29A @ 120VAC (348watts vs 3480watts)

This is not exactly true.  29A is 29A for the most part.  We've ran 26,000 watts on 12 guage wire.  Amps matter on wire size, not watts.

Do NOT NOT NOT undersize the wire.  You will forget and you will start a fire.  If you want to do this, then put a fuse to protect the wire.  As long as you fuse it properly, then this would be acceptable.

Watch out for voltage drop too.  This will increase your amps.  Find a voltage drop calculator.  I would guess that anything over 25 feet on 12 volts could start to present problems.

Run parallel runs (multiple wires carrying the current) is a good idea, except that the lugs (the place where you land the wires) are not usually not made for multiple lugging.  Look at some device that can combine the wires and make them so only one logical wire is on the lug.

[rm357]

The recommended gauge for house wiring also considers the voltage drop over the length. For very short runs like a foot or less, you can get away with smaller gauges. 12 gauge should be fine or doubling up a couple of 14 gauge.  A single 14 gauge is probably going to start getting hot...

[zwiller]

Thanks so far. 

Here's the chart I found: You are not allowed to view links. Register or Login  Might not be correct as I found another with conflicting info.  You are not allowed to view links. Register or Login 

Perhaps you guys can recommend a better site you trust and I will bookmark...

I am only using 80 watts this year so I can can scale back but I will probably forget, overload it next year, and fry it.  Just trying to do the right thing now. 

[caretaker]

Here is one from a Solar Electric company that will work for what we are doing (make sure to look at the 12 volt chart)
You are not allowed to view links. Register or Login   #10 wire is good for 6.6 feet or less so if your power supply is right next to your MR16 use #10 wire.