November 15, 2023

How to understand low current engineering drawing identification icon

ForewordHello everyone, I'm Mr. Lin. The design and construction of low-voltage intelligentsia will definitely require drawings. Therefore, first of all, it is very important to understand icons of low-current drawings. What do marked symbols mean and what do icons mean? Once understood, drawings are easy to read. Text

In order to understand engineering drawings, there are drawing design instructions, what each letter stands for, and most low current signs:

  • SR: laying on a steel cable
  • BE: installation along truss or across truss
  • CLE: stacking along columns or across columns
  • WE: laying along wall
  • CE: installation along surface of ceiling or roof.
  • ACE: laying on ceiling where people can enter.
  • BC: Concealed laying in beam.
  • CLC: hidden in column.
  • Toilet: hidden in wall.
  • CC: Concealed ceiling gasket.
  • ACC: Hidden in an inaccessible ceiling
  • FC: Hidden laying in ground
  • SCE: laying in ceiling, carrying metal pipes
  • 1

    1. Indication of passage of wire through pipe

  • SC welded steel pipe
  • MT-Canal
  • PC-PVC Rigid Plastic Pipe
  • Rigid FPC tube
  • CT bridge
  • MR metal box
  • M-cable
  • CP metal hose
  • PR plastic box
  • Galvanized steel pipe
  • 2

    Secondly, presentation of wiring methods

  • Direct tombstone
  • TC cable trench
  • BC-Hidden in beam
  • CLC cover in column
  • Toilet-hidden in wall
  • CE installation along ceiling
  • CC-hidden in ceiling
  • SCE-False ceiling installation
  • F-floor and bottom slope
  • SR - Along Rope
  • BE-along truss, beams
  • Laying WE-surface along wall
  • 3

    Third, how to install lamp

    CS chain crane

    DS-pipe faucet

    W-wall mount




    CL column

    Along wire groove: SR

    Along truss or across truss: BE

    Along column or across column: CLE

    Laying through a welded steel pipe: SC

    Conduit installation: MT

    Laying through rigid plastic pipe: PC

    Laying through non-combustible semi-rigid PVC pipe: FPC

    Cable tray installation: CT

    Metal box: MR

    Laying plastic box: PR

    Steel cable laying: M

    Laying corrugated PVC wire: KPC

    Metal hose laying: CP

    Direct burial: DB

    Cable in trench: TC

    Marking wire location

    Laying along or across beams (trusses): AB

    Hidden in beam: BC

    Laying along or across columns: AC

    Concealed stacking: CLC

    Laying along wall: WS

    Hidden in wall: toilet

    Laying along ceiling or roof surface: CE

    Hidden roof or roof gasket: CC

    False ceiling installation: SCE

    Outdoor or underground installation: FC


    DTQ30-32/2P These two types of molded case circuit breakers should be of two types,

    HSM8-63C/3P suitable for lighting circuits, is a 3-pole switch with a rated current of 63A (3-position switch)

    DTQ30-32/2P is also a type of molded case circuit breakers, rated current 32 A, two-pole switch


    Fourth, there are security product icons. It is also often seen in drawings.

    System name icon Symbol

    Perimeter alarm ZJ-xx-T(R) xx indicates a pair of xx active infrared detectors, T indicates a transmitter, R indicates a receiver.

    DS-xx xx TV Monitor represents xx camera.

    Doorphone LM-xx LM stands for call station, xx stands for call station of unit xx.

    LS-xx-yyyy LS stands for indoor unit, xx stands for xx block, and yyyy stands for door number yy on floor yy of this block.

    LW-xx LW stands for guarding machine, xx indicates guarding machine number xx.

    LG-xx LG stands for control vehicle, xx stands for control vehicle No. xx.

    Home alarm JJ-xx-yyyy JJ stands for alarm keypad, xx stands for device number, yyyy stands for yy device layer yy

    Door number.

    JT-xx-yyyy JT is infrared sensor, xx is unit number, and yyyy is yy floor yy unit door number.

    JM-xx-yyyy JM is magnetic door switch, xx is room number, and yyyy is door number yy on floor yy of room.

    JA-xx-yyyy JA is emergency button, xx is block number, and yyyy is yy door number of block on yy floor.

    JQ-xx-yyyy JQ is gas detector, xx is unit number, and yyyy is yy floor yy unit door number.

    JY-xx-yyyy JY is smoke detector, xx is room number, and yyyy is yy floor yy room door number.

    Electronic Patrol DZ-xx-yy DZ is patrol button, xx is patrol route, and yy is yyth tour

    Edit button.

    Access Control MJ-xx-yy MJ stands for card reader, xx stands for device number, and yy stands for yy card reader of device.

    Global Address GB-xx-yy GB indicates speakers, xx indicates partition number, and yy indicates number of speakers in partition.

    Equipment control BA-DT-xx DT - elevator control, xx - building number.

    BA-SX-xx SX means water tank monitoring, xx is unit building number.

    BA-SB-xx SB - water pump control, xx - pump number.

    BA-ZM-xx ZM - lighting control, xx - circuit number.

    BA-HK-xx HK — aircraft obstruction lights control, xx — number of aircraft obstruction lights.

    BA-ZS-xx ZS – catchment well monitoring, xx – number of catchment wells.

    BA-DDC-xx DDC is BA control unit, xx is number of control unit.

    Integrated Cabling System TD-xx-yy-zz TD stands for data data point, xx stands for building number, yy stands for floor, and zz stands for room number.

    TP- xx-yy-zz TP means voice information point, xx means building number, yy means building Floor, zz means room number.

    TV- xx-yy-zz TV means TV outlet, xx means building number, yy means floor, zz means room number.

    LAN-xx-yy LAN means large log cable, xx is device number, and yy is number of large log cables for this device.

    FTTP-xx-yy FTTP means optical cable, xx is device number, and yy is number of optical cables in this device.