The LearnDB suggests that you should not consider taking on the Zot dungeons without some source of rElec. However, I have never found so far any item that granted such a protection, except for potions of resistance and spells.
What is a reliable source of electric resistance in Dungeon Crawl?
Best Answer
There are very few guaranteed sources of anything in Crawl. As of DCSS 0.15, the ways to resist electricity are:
I believe the maximum damage from electric golems and titans has been toned down in DCSS (I think they could one-shot some very-low-hp character builds back in 4.0b26), so permanently-on resistance is less mandatory than it was back then. On the other hand, there are now more shocking monsters (draconians), and there is more risk of needing all resistances at once (draconian packs). I think that in DCSS, electricity resistance isn't really mandatory anywhere for mid-to-high HP characters.