Electrical Flashcards
What is continuity test used for?
Used to check resistance values
Used to check that the cable is continous
L or N x (?) = earth resistance value
1.67
Difference between live and neutral should be less than (?)
0.5
Whats the minimum reading aloud of insualtion resistance
1M ohm
What sized cable for is suited for a cooker?
6mm
What sized cable is suited for a shower?
10mm
What is the earthing system value of TNC S?
0.35 ohms
Earthing system value for TNS?
0.8 ohms
How do you find R1 + R2 when you have found the Ze and Zs?
Ze-Zs = R1+R2
What is Ze and where would u test it in a house?
Ze= external Impedance
Test it at board(main switch)
(Remember by knowing external means “out with” aka outwith the board back to the main supply)
What is Zs and where would you test it in a house?
Zs= Internal impedance
Tested at the house points =sockets,lights,cooker etc
Wiring recess less than ??mm from a wall surface requires to be RCD protection
50mm
What should you do to the kA in a 3 phase board
Double the kA because 3 phase could be short between 2 phases
What is the earth/bonding cable size of doube installed ?
25mm
What is the earth/bonding cable size of the main earth?
16mm
