Greenfield is the trade name used for flexible metal conduit (FMC), an empty helically wound metal raceway that conductors are pulled into after it is installed. It is used for connections to motors, transformers and fixtures where vibration or alignment rule out rigid raceway, and for short runs through tight spaces. Its use as a grounding path is limited by length and circuit size, so most Greenfield runs carry a separate green ground wire.
Drop three feet of Greenfield from the J-box to the transformer so the hum doesn't crack the fittings loose.
Also heard as
- flex
- FMC
- flexible metal conduit
Do not mix it up with
- BX: BX is a factory cable with conductors already inside the armor; Greenfield is an empty raceway you pull wire into.
Related terms
Sealtite
Liquidtight flexible metal conduit: flexible steel conduit with a gray plastic jacket, used at motors and outdoors.
BX
Trade name used for armored cable: insulated conductors inside a spiral metal jacket.
Whip
Short flexible conduit or cable assembly with wires already in it, linking a fixture or machine to a junction box.
MC cable
Metal-clad cable: insulated conductors, including a green ground, inside interlocked aluminium or steel armor.