NSMS Alternative Fuel Technologies

This is a standard AWG wire gauge selection table which extends the usual wire gauge selections by taking into account cable runs before voltage drop occurs. Why is cable length important? If you are powering something simple, like lighting up a lightbulb or running a light appliance, voltage drop may not be a factor for you. However, high-demand items such as a PWM and HHO cell will experience "brown out" conditions if significant voltage drop occurs, resulting in heating of the wire and the PWM/HHO cell components as a result (much in the same way that an electric motor, such as a heater or air conditioning fan, under brown-out conditions will heat up and could burn out).

For the 20 amp PWM included in the COSM-III, 12 gauge wire is the minimum that should be used. Looking at this chart, the servicable area is highlighted because we are concerned not only with amperage but also wattage. At 12 volts, the PWM at max power on the HHO cell will draw 240 watts. Given that your cable length will be AT LEAST 7 feet (and most likely longer because a cable run between cabin and engine compartment takes more cable than you will initially think), and given that your watts needs will run between 240 and 300 watts at the maximum (your 12 volt electrical system produces closer to 14 volts when running and charging which means you could pull closer to 280 watts), you can easily see why 12 gauge wire should be your minimum selection. You also want to give yourself plenty of margin for safety so that you minimize any chances for undue heating or voltage drop (and the strain that would put on the PWM in particular, due to its load which is the HHO cell). Good advice would be to engineer for plenty of capacity now and save yourself costly repair or replacement (due to under-engineering) later. You will always need more cable than you think. Cable runs are almost never straight-through. Most people figure that 5 or 6 feet is more than enough because the engine isn't that far from you in the driver's seat. What those people fail to realize is that you have to route the cable around things to get it where it needs to go. You'll use up 5 or 6 feet....or even 10 feet, in no time. Keep this in mind as you attempt to right-size your installation.