Quote:
Originally Posted by hanleyclifford
The 3% voltage drop mantra is arbitrary and violated everywhere with impunity. Read the source of it and you'll see why. Sizing of fuses should be based on actual load, not a recommendation, and we have seen what can come of studious attention to manufacturer's propaganda. (remember Pertronix?)
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Hanley - I really don't understand where you're going here. Are you dissing the NEC and ABYC? These are well intentioned, and well supported fire safety codes.
3% is an excellent design goal, and inherent in that calculation is the circuit design current, ampacity of the wire, the temperature of the space, and ultimately the fuse requirements.
Numbers greater than 3% will work, no doubt for a while, but the risk is a runaway thermal reaction - as voltage drops, the current goes up, heating the wire, which increases it's resistance, which further drops the voltage, which increases current, which eventually burns the insulation and shorts.
I've burnt up extension cords doing just this.
I don't know why you'd want to recommend ignoring this.