How does the shorting block really change anything as far as shutting the power down and the electrical safe work practices?...
That aside I would say the only safe OSHA compliant way is to shut the building down. (And if you install the shorting blocks you would only have to do this once.)
I have a power quality meter that needs to be sent back to the factor for calibration. What is the best way to disconnect the CT leads on the meter without having to shut down the building.
Do not open circuit the seconday of a CT with load on the system, you need to short the seconday of the CT, there should be shorting blocks to do this and if not you will need to shut down the system.
They're used like a make-before-break switch. The shorting wires/jumpers/bars bridge the CT's metering terminals before(!) disconnecting any metering wires.How do the shorting blocks work? I have never used them.
So the shorting Block just completes the circuit. Will there me something I have to switch so that they are shorted out. I am not there so I am just asking questions blindly.
disregard my last message. These meters do have shorting blocks. So do I just just shut power off the meter, Install the screws, and then at that point I can disconnect the leads that go to the meter.
disregard my last message. These meters do have shorting blocks. So do I just just shut power off the meter, Install the screws, and then at that point I can disconnect the leads that go to the meter.
You don't have to shut the power off to the meter first, in fact you can verify the ct was shorted if you leave the meter powered and watch the current drop to 0.
If the current drops to zero the current path is probably open, not shorted. The shorting screws will cause the current read by the meter to drop because there is now a parallel path. I would expect that if the meter is functioning it will still read some current. A clamp-on type amprobe can be used to verify each phase reading has been reduced after the shorting screws are in place, if the meter is dark.
Get a current reading before & after installing the shorting screws. The measurement will not change on the wires between the shorting block and the CTs. It will be lower on the wires between the shorting block & the meter.