Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

EM-M

IEC

Maintained emergency luminaire plan mark

A maintained emergency luminaire operates as a normal light and continues on battery when the normal supply fails. Plans usually draw the luminaire mark with an emergency indicator, such as a filled segment or a letter E, plus an M or maintained tag.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Emergency luminaire, maintained. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A non-maintained emergency luminaire lights only on supply failure; the maintained form is lit continuously.

Full reference

EM-NM

IEC

Non-maintained emergency luminaire plan mark

Non-maintained emergency luminaires stay off while the normal supply is healthy and light from their internal battery on failure. Plans show the emergency luminaire mark with NM or with the legend distinguishing it from maintained fittings, typically along escape routes and at changes of direction.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Emergency luminaire, non-maintained. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A maintained luminaire is lit continuously; this one only lights on failure.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.