TDR failure

Status
Not open for further replies.
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
I tried to locate faulted conductors, distance to, in a buried 2" RMC.

For the experience of frustration I tried the TDR.

It showed 7.5 feet on one end and 12.5 on the other of a guesstimated 150' run of conduit with 50+ wires. The 7.5' = distance to where open conductors entered the RMC at the MCC , and the 12.5'= distance to where RMC entered earth at the load end. Tested conductors were very short on this end. I could not seem to adjust the TDR to make any difference that I could read for the second bump.

For the TDR users, would cutting the tested conductors as short as possible at the MCC end have helped with this reading?
 
Hello;

First time reply-er here, so bear with me, I'm primarily a Broadcast Engineer but have used TDR's in my work.

The TDR's that I'm familiar with (Tektronix 1502, 1503) have a multiplier setting for 'Distance' and it's easy to have it set on the wrong range.

It sounds as if maybe that's what happened, from your figures, I'd say your conduit may be closer to 200 feet and it is telling you that the problem is 75 feet from one end and 125 feet from the other.

Just a guess based on my many frustrating experiences with TDR's...great devices when they work, hair-pullers when they don't.

Regards,

Gary
 
The VOP is dependant on conduit, conduit type, and how many conductors are in it. Never tried any with 50+ in it, but that may be a problem.... What I would do in as situation like this is to get a new VOP # by using a set of known good conductors in the same conduit or path, and dail through the numbers until you get as close as you can to what you're looking for. i.e. ~150-175' open - and then short the conductors at the other end and see if it still stays at near the same number of feet. Then after you get that VOP# use it to test the bad conductors.

Also - have you checked the batteries in the unit? :rolleyes: One of mine would do something simular from time to time - not show 'low battery' until it was REAL low.... So the unit would not have enough power to bounce past obstructions - like say the initial entrance of the conduit - which in your case is packed.
 
Status
Not open for further replies.
Top