Digital Electronic Energy Meters

An open secondary on a CT is dangerous if energized.

Current transformers are never fused for safety reasons, the fuse (or similar protective device) would actually create a more dangerous situation than if it were just left out.

http://en.wikipedia.org/wiki/Current_transformer

A common method in the power and instrumentation industries is to instead install shorting links to allow the CT output to be shorted for maintenance or live removal, however I doubt this is applicable or necessary for your application.

The load of a CT is characterized as "burden". Meaning the CT has to be balanced with a meter load circuit that is stable.

A fuse in this line compromises the efficiency of this circuit because of a big difference in conductor size and the permanent change in conductivity between a cold and hot fuse wire.

(Burden mostly ranges in values lower than 0.5 ohms).

A electronic meter starts fusing the electronic circuits, loose from this circuit - it is IN the meter printed circuit.

CTs work on Short circuit basis. A fuse is not Useful BUT detrimental as follows:

if YOU OPEN THE CIRCUIT when there is a current flowing in the main cable (Primary), the Voltage at the Open ends will be very HIGH and will start destroying the CT windings: This will result in burning the winding due to shorts created by the very high voltage. (Sometimes it might explode) but then evrything stops as soon as the CT is compromised.

Salahuddin Zia,

A CT is a transformer in which the design is a ratio of primary current to secondary current, not voltage to voltage. Thus it is inherently current-limiting. As others have said repeatedly, an open-circuit on the secondary of a CT is potentially dangerous whereas a short-circuit is fully within its design capabilities. Thus, a fuse is not only unnecessary (current-limiting design) but potentially dangerous (uncontrolled open-circuit voltage). In ammeter switches, where one meter can read any of the CT's on a 3-phase system, the wiring of the switches short-circuits the CT's that are not connected to the meter.

--JMM

rvt is provided