Akademik

в Тулу со своим самоваром не ездят
В ТУЛУ СО СВОИМ САМОВАРОМ НЕ ЕЗДЯТ{{}}
[saying]
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there is no need to bring sth. to a place that already has an abundance of it:
- why <don't> carry water to the river. Cf. it's useless to carry <it would be like carrying> coals to Newcastle.

Большой русско-английский фразеологический словарь. — М.: ACT-ПРЕСС КНИГА. . 2004.