williangomes.a

Hi comunity, I'm using a bta41-600B to control a shower (resistive load purely), using an arduino and zero cross detection to control over phase angle, the circuit draws aproximately 38 amps, triac is mouted in a good heatsink, but as when i increase the voltage in the potentiometer, when it draws more than 25 amps for example, the triac start self triggering and doesn't dimmer anymore(the voltage increase at maximum, even removing the gate signal the triac keeps on at full voltage, i've tried using a capacitor and resistor (39R and 100nf) as a snubber but doesn't work, I've changed the triac but It always happen, thanks for any help.