15) Which one of the following materials is used to fix the screw on concrete wall and ceiling ?

16) You have to install cables for a switch board using clips on batten. The distance between the accessories is 3.6 m. How many clips do you need for horizontal run of the cable ?

17) In the metal conduit system of wiring where there is zig-zag wall projection the cables can be run using :

18) For tapping supply from mains to different branches three types of layout for wiring system are used. As per IE regulation, one ring main circuit has to be there for every specified floor area or plant there of. How much is this area ?

19) The only wiring which has to be planned well before starting of a house construction work and executed along with construction is :