False reading

G

Grant1969

New Member
Checking why I thought was a dead cable before cutting it I am getting strange readings.

my fluke t6 is showing 0 voltage directly on the wires but 80-155 volts on the field sense.
I understand this could give false readings but my cheap voltage tester stick is also picking up voltage.

just to be clear I have tested the cables on the fluke on a working 240v power source and they seem to check out perfectly.

Any ideas why this would be happening?
 
What is field sense? Like a non contact indicator? What are you testing between? This might also be why an approved voltage indicator or test lamp only are used.
 
LearnMore said:
What is field sense? Like a non contact indicator? What are you testing between? This might also be why an approved voltage indicator or test lamp only are used.
Click to expand...
Field sense is fluke’s non contact voltage indicator. It’s not perfect by any means but it’s odd that I would pickup a reading in this as well as a cheap voltage stick while wired meter reads 0
 
You are using the testers for things they are not designed for. In general a tester that senses the electric field round a conductor is for proving live, not proving dead. These are two very separate requirements.
 
adgjl said:
You are using the testers for things they are not designed for. In general a tester that senses the electric field round a conductor is for proving live, not proving dead. These are two very separate requirements.
Click to expand...

this is my point. I have a generic voltage stick tester and the fluke are showing a current. The test leads are showing 0.

my question was why the discrepancy
 
Grant1969 said:
this is my point. I have a generic voltage stick tester and the fluke are showing a current. The test leads are showing 0.

my question was why the discrepancy
Click to expand...
Because basically you don't understand what your meters are telling you, so are therefore misusing them.

Sorry if that sounds harsh, but that really is the sum of it.
 
Grant1969 said:
I know exactly what my meters are showing. I don’t understand the discrepancy
Click to expand...
You don't understand th discrepancey because you don't understand what they are telling you.

The correct test with the probes is telling you there is nothing present.

The non-contact readings are detecting an induced voltage. Short out the end of the cable (with power off) then retest and your non-contact voltage will also be zero because you have discharged the cable.
 
A lot of good sense on this thread, OP. Also, not trying to be awkward, but why cut the cable rather than trace it back to source and disconnect correctly ?
 
WH55 said:
A lot of good sense on this thread, OP. Also, not trying to be awkward, but why cut the cable rather than trace it back to source and disconnect correctly ?
Click to expand...
It is disconnected correctly from the source correctly. The cable is routed through inaccessible areas so I have have unclipped to that point and have several meters of cable tied up. Before cutting I went to double check and came across the issue.
 
Grant1969 said:
I know exactly what my meters are showing. . .
Click to expand...
You are reading the indication, but you do not understand what it is telling you. You cannot use a non-contact device to prove a conductor or cable dead. It follows that you cannot safely use it to determine whether you can cut a cable. You have three options:
- follow the cable from a point where you can access the conductors, and follow the cable back to where you wish to cut it.
- use live jointing techniques to access the cores at the point where you wish to cut it (I suspect you do not have the training to do this safely).
- turn off all the power and hope for the best (not recommended).
 
You must log in or register to reply here.
Back
Top