PR S 40012

Question 1

What is the general rule for wire replacement

Answer 1

change over one wire at a time

Question 2

what must be done after completing the repair

Answer 2

adequate testing to ensure the integrity of the repaired wiring

Question 3

when does a signal engineer need to test the repair of cables

Answer 3

more than one single wire/multicore cable of the same size and type is broken.
more than one wire of an existing circuit is to be disconnected.
if a signal wire is to be replaced by a multi-core.
when planned rewiring on other than a like for like basis.

Question 4

Single-wire replacement

Answer 4

Book out apparatus
Identify and label both ends.
Ensure no intermediate terminals or contacts.
Ensure it does not go through any intermediate location.
Run and prepare the new wire and keep insulated.
Disconnect affected circuits.
Disconnect defective wire
Immediately connect new wire one at a time.
Remove wire or secure and label defective.
IR test new circuit to earth.
Strap and function to one clear series contact.
Re-connect affected circuit.
Book back into use.
Advise signal engineer and submit detailed report.

Question 5

Multi core cable repair

Answer 5

Book out apparatus
Identify and label cores at both ends.
Open contacts at immediate terminals.
Conduct continuity test to ensure no continuity.
Join at the break and carry out continuity to confirm repair.
IR test new circuit to earth.
Function test each circuit with voltmeter on end funciton.
Re-connect affected circuit.
Book back into use.
Advise signal engineer and submit detailed report.