Page 520 - Handbook of Electrical Engineering

ABBREVIATIONS COMMONLY USED IN ELECTRICAL DOCUMENTS 511

LED Light emitting diode.
LEL Lower explosive limit.
LF Low frequency.
LHS Left-hand side.
Lloyds Lloyds Register of Shipping (UK).
LMS Load management system.
LNG Liquefied natural gas.
loc or (L) Local operation.
LPG Liquefied petroleum gas.
LSDS or LSS Load shedding system.
LSF Low smoke and fumes, applied to cables and wires.
LSLH Low smoke low halogen.
LSRS or LSR Load sharing system.
LV Low voltage, 51 to 599 volts.
L1, L2, L3, N Notation for line and neutral voltages and currents.
LUX Level of illumination.

M

m Length or dimension in metres, or month.
mA Current in milli-amperes.
man or (M) Manual operation.
mbar Milli-bar.
MB High-pressure mercury, without phosphor coating.
MBF High-pressure mercury, with phosphor coating.
MBFR High-pressure mercury, with phosphor coating and internal reflector.
MBI High-pressure discharge with metallic halides.
MBIF High-pressure discharge with metallic halides, with phosphor coating.
MBR Double-ended linear arc tube.
MBTF Combination of MBF lamp and a filament lamp.
MCB Miniature circuit breaker.
MCC Motor control centre.
MCCB Moulded case circuit breaker.
MCF Switch-start lamp, also used for tubular fluorescent lamps in general.
MCFE Starterless lamp, coated with silicone.
MCFA Starterless lamp, with earth strip, mainly used in cold environments.
MCR Maximum continuous rating.
MCU Motor control unit.
MESG Maximum experimental safe gap.
Mho Unit of electrical admittance.
MIC Minimum ignition current.
MICC Mineral insulated calander cable.
MIMIC Mimic display panel.
mm Length or dimension in millimetres.
MMF or mmf Magneto-motive force.
MMI Man–machine interface.
MMSCF Million standard cubic feet of a gas.