earth wire in multicore control cable 1

[MAZ13]

Dears,

some type of multicore control cables are available in the market, which provide an additional ground wire. It means a 5x2.5mm2 cable consists of 5 of 2.5mm2 wire and a ground wire (typically in green and yellow colour).
I would like to know what is the application of this type of cable.
Where should a control cable have a ground wire?
What is the role of ground wire in this control cables?

Thanks

 

[Padlock01]

Hi Maz13,
Depending on the application control cables we use RSA is 2c,3c,4c,7c,12c all the way to 37c in 1,5 2,5 mm2 take a 7c/2.5mm2 cable for 230volt lighting 6cores are for
RN,WN,BN and earth. or for control depending on the clients specification if one uses 230volt control for motors i would certainly use an earth core.
or with 110volt ac control voltage with the secondary side of control transf. say 525/110volt ac with the centre tap earthed i would not need an earthing core at a pushbutton station - anyway we use the cable armouring as a backup. I hope this helps??