[HCARC] Radio Shack Electrical Requirements

[Dale Gaudier]

Gary:

I assume the 35/50/75 amp power supplies you mention refer to the maximum current they put out at 12V DC (actually 13.8V DC). The current draw on your regular 110V AC wiring will be much less. Recall that power in (E x I)  = power out (E x I), less transformer/conversion losses. So a 35 amp 12 V output implies an input current of around 5 to 7 amps at 110V depending on the efficiency of your power supply. The gauge of wiring you will need will depend on whether you are talking about the supply side (from your breaker box to your outlet) or the DCvoutput of your power supply.

A commercial power supply will have the required input voltage and current and output voltage and current stated on its case somewhere. You should be able to get this info from the manufacturer's Web site.

On the supply side, the maximum current you can run on #14 AWG copper wiring is 15 amps  and 20 amps for #12 AWG wiring (per Code). For 110/120V lines I would only use #12 or greater. If you plan to have a legal limit amp (1500 watts) you will want a dedicated 220/240V line. The maximum current draw at 220V AC will be around 11-12 amps, slightly less at 240V. I recommend using #10 AWG copper wire to give you a margin of safety in case of a fault. Run this off a dedicated 20 amp 220/240V breaker in your breaker box.

On the output side, assuming a reasonable length of wiring from the 12V DC power supply output to your radio and accessories of 15 feet or less, you will need a minimum of #8 AWG copper wire for up to 30 amps and #6 AWG copper wire for up to 50 amps. 

BTW, a 25 amp/12V supply will be more than sufficient to power any 100 watt transceiver. So, unless you're planning to run several other high current 12V devices off your power supply there is no need to pay for extra current capacity you will never use. You can then use #8 wire for your DC connections.

BTW, if you are considering gettng an amplifier, do check to see what your actual line voltage is. Amplifiers usually have taps on their transformers that can be set for the actual line voltage. At my ranch, the line voltage is 120/240V, so my amplifier is set up accordingly.

73,

Dale - K4DG


On Nov 1, 2012, at 4:16 PM, "Gary and Arlene Johnson" <qltfnish at omniglobal.net> wrote:

> Since I am still constructing my radio shack and even though I plan to power my radios off of solar charged golf cart batteries for the most part I will have the availability of 110 volt current to run power supplies if necessary.  
> 
> To run 35 amp power supplies or for that matter 50 or 75 amp power supplies, do I need to install heavy duty wiring (6 gauge)and 40-60 amp circuit breakers or will 20-30 amp circuits and 10 gauge wiring be sufficient??  I need to know because at the beginning when the walls still haven't been closed is the time to make these decisions.
> 
> Thanks for the help.
> 
> Gary J
> N5"BAA"
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