something i pulled from wow wiki , useful i think
Shockadins generally cause very little physical damage; usually they use Judgement of the Crusader to increase their holy damage. Then they have a few options to deal their damage but they capable of inflicting high damage in short periods of time. The most popular spell will be Holy Shock, if possible combined with Divine Favor. Another important source of damage will be their Judgement spell combined with Seal of Righteousness. Shockadins can also use Consecration to do surprisingly dangerous AoE damage. In addition, Avenging Wrath can be combined with Divine Favor for huge Holy Shock crits.
Shockadins are reknown for their massive burst capabilities, and paladins that seriously gear for the spec are a significant force in pvp. As Holy Shock, Judgement of Righteousness, Divine Favor, Avenging Wrath and Trinkets will only trigger 1 global cooldown when tied together in a macro, the shockadin can deal upwards of 4000-7000 damage in a single click. At this point, the shockadin can potentially follow up with a Hammer of Wrath to finish of opponents.
However, many of the shockadin's spells are on long cooldowns, especially Holy Shock, which takes 15 seconds before it can be used again. While Judgement of Righteousness is on an 8 second cooldown. The lack of sustained DPS means that shockadins only truly excel in duels against a single opponent, where a well timed burst is enough to end the fight. In longer drawn out arena battles, a shockadin may be useful for bursting down an opposing healer, but after all cooldowns have been popped, most shockadins end up healing his allies, and a lack of specialisation into the protection tree means that healing is made more difficult, as heals may be disrupted by attacks. However, it is possible to follow a shockadin spec while still retaining 5/5 Spiritual Focus, which eliminates most of this problem.
Many raiding holy paladins enjoy this spec as it allows them to heal in raid content while still doing decent damage for pve, especially dailies. The only true difference between a Shockadin spec and a normal raid spec is the loss of Blessing of Kings and Divine Illumination.