Zaphael was a Forgebright. Ethersurge being one of his two Tertiary Styles, he couldn't actually use any of the five Surges. Not really. So instead, he Forged all of them as Skills using his Primary Aspect. Genius would be an understatement.
The glowing sparks that zipped about his body, energizing his strength, honing his senses, pushing him to move against the coordinated assault of the goofy Legion Master's Golems, were not part of his Ethersurge but of his Etherskill.
Through this Forgeskill, he could mimic all five of the Surges. When he tried using Ethersurge, it felt to him as if he was trying too hard to even just flow his Ether through his body, but while using this Skill, Volta itself was running through his veins. That had inspired the name for it.