Just curious why the red & black leads from my multimeter get quite warm when measuring higher dc current under a 20A setting? First I measured 4-5amps for 20secs & the leads didn't get warm, then measured another system with 16-17amps draw & within 5 seconds it got quite warm. Not like its over 20A. Are you just meant to hold it on the circuit for a few seconds? Why is it you can hold the leads when measuring voltage for a long time, but not current?