Can Ammeter Run Parallel?

[baskin]

TheMonkey; your theory is correct, to be more exact, you’ll find a wire resistance chart here http://www.stealth316.com/2-wire-resistance.htm What you’ll need to do to calculate the split is to first find the resistance of each path, then convert that resistance to conductance (1/R) and then find the percentage of conductance for each path. As an example, let’s say you have 10 feet of 10 gauge bypassing the ammeter, giving a resistance of .0102 ohms, and 15 feet of 12 gauge running through the ammeter path, giving a resistance of .0243 ohms. The conductance of the bypass path = 1/.102 = 98.4 S, the conductance of the ammeter path = 41.15 S, and the percentage of current through the ammeter = 100* 41.15/(41.15+98.4) = 29.49%. The resistance given is at 77F and will rise about 6% for every 20 degrees F but, given both paths are at relatively the same temperature, it won't change the final numbers much.

For safety reasons, you'll want to use a fusible link on both paths, the correct gauge for that should be 4 gauge numbers higher than the wire being used, eg; 10 gauge wire would require a 14 gauge fusible link. Finally, remember that the function of the link is to get hot enough to melt the copper on overload, which will also melt solder, so although you can solder the connections to the link, they need to be primarily attached mechanically (crimp connector)