Disconnecting an Ammeter from a Current Transformer (CT)

Haven't done this before...(So I might be wrong)

But definitely, Short out your CT circuitry, THEN remove the meter.

And if you could turn off the power in the first place, do that first.

http://cr4.globalspec.com/thread/38424/Disconnecting-Ammeters-from-Current-Transformers

1. Isolate power to the equipment.
2. Disconnect and remove ammeter.
3. Blank-off ammeter panel hole so as to maintain ingress protection rating of the panel.
4. Either short-out the output terminals of the current transformer, or remove it.
5. Close panel door and re-energise.

Haven't you read CR4. We had just discussed it last week.

It should first be understood that a current transformer is normally shot-circuited in operation. The secondary current produces a powerful magnetic counterflux. If this disappears for some reason; low load or disconnection of the measuring instrument as in the case being discussed, the primary current would generate a very high magnetic flux. This would overheat the core and generate an excessive voltage in the secondary winding, possibly damaging the insulation.

For this reason no fuses may be fitted in the secondary circuits of current transformers. Whenever the measuring instrument is disconnected, the secondary must be shorted across first. An easy, efficient and convenient way of doing this is through the use of shorting terminal blocks on the secondary of current transformers, which automatically short circuits the instrument transformers when the load is removed.