Electrical wiring monitoring

Mark, there are so many articles in the web through which time domain reflectometry is recommended as a method of monitoring the aircraft wiring onboard presumably such as three phase supply wiring of pump, right? Correct me if I am wrong. However it is not clearly specified how the signal should be injected into the wiring bundle. So I am afraid it requires cutting bundle wires for removing insulation and then splicing after TDR test.......would you mind explianing how TDR may be used to inject signal into three phase feeder wiring?

I guess you could map (record) an image of the wires in a normal working condition with a TDR, but I really don't know if that will help in the long term.

If any systems that needed to be verified in a working condition..... it would be the co-ax wires to all the antennas.

If you really wanted to record the three phase wiring to your fuel pumps there would be no need to splice in anywhere. You could disconnect the wires from the power relay and shoot back towards the pump or tie-in at the disconnect plug just downstream of the relay.

Your TDR display should show a slight bump for the splices and then go straight down (indicating a short) when the signal hits the pump. If the plug is off at the pump, the line will go up indicating an open.

The total wire distance to the pump could be noted also.
  
  
 
  
  
When we have pump wiring issues..... we first check continuity with the VOM and then we hit it with a  Megger to show us if we have a short to ground or wire to wire.

If you had a previous mapping of the wire, the TDR would certainly show the approximate location of the problem.