TL;DR
NM-B cable is the nonmetallic-sheathed wiring — universally called Romex — that carries most branch circuits in US homes: insulated conductors and a ground wrapped in a plastic jacket, color-coded by gauge with white for 14, yellow for 12, and orange for 10. The B suffix marks the modern 90-degree-C insulation, though ampacity is still taken from the 60-degree column.
What it means
NM-B cable is the nonmetallic-sheathed wiring — universally called Romex — that carries most branch circuits in US homes: insulated conductors and a ground wrapped in a plastic jacket, color-coded by gauge with white for 14, yellow for 12, and orange for 10. The B suffix marks the modern 90-degree-C insulation, though ampacity is still taken from the 60-degree column. It is limited to dry, protected locations, which is why exposed runs in garages and outdoors need conduit or a different wiring method.
Where it sits in the glossary
NM-B cable is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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