If you cannot afford the full standard, there are legal ways to access its content without piracy:
Some universities, research centers, and public libraries (especially those with engineering programs) have institutional subscriptions to ABNT’s collection. If you are a student or professor, check your institution’s library portal – you may be able to download NBR 5410 for free or at a reduced rate. nbr 5410 download
20 Jul 2018 — NBR 5410 2008 Inst Eletricas Baixa Pot : Free Download, Borrow, and Streaming : Internet Archive. Internet Archive ABNT NBR 5410 If you cannot afford the full standard, there
No. ABNT does not provide official free PDFs of NBR 5410. Only free reading at physical consultation points is available. Beware of any website claiming to offer a "free ABNT download." Internet Archive ABNT NBR 5410 No
Many professional associations (e.g., CREA, ABRADEE, SENAI) publish free guides, checklists, and summaries based on NBR 5410. These are not substitutes for the full standard but can help with everyday tasks. Search for "Guia prático NBR 5410" or "Resumo NBR 5410" from reputable sources.
is the Brazilian National Standard (Norma Brasileira) regulated by ABNT (Associação Brasileira de Normas Técnicas). Its full title is "ABNT NBR 5410: Low Voltage Electrical Installations" (Instalações Elétricas de Baixa Tensão).