"They put water on the fire."
Translation:Chuir siad uisce ar an tine.
You're referring to the "deNtals-dots" rule, since N is the preceding letter? I always forget that.
No; I’d thought that “DeNTaLS-DoTS” referred to when lenition would not be applied to an indefinite genitive noun following a plural noun ending with a slender consonant, e.g. cupáin bhainne (“cups of milk”) but cupáin tae (“cups of tea”).
What I’d had in mind is that in the Caighdeán, several prepositions followed by an and a noun neither lenite nor eclipse the noun if the noun begins with either D, S, or T — ag an doras, faoin talamh, leis an solas, etc. But as galaxyrocker pointed out, a noun beginning with D or T would be eclipsed in Munster Irish (and in Connacht Irish, a feminine noun beginning with S would get T-prothesis).