CURRENT transformers (CTs) are inexpensive, accurate devices for monitoring ac current for measurement and transducers.
If properly sized and installed, they will give many years of trouble free service with no adjustments to make.
However, care must be taken to never open circuit a CT secondary while the primary is energised. High crest voltages may occur across the open secondary circuit.
To avoid personal injury or equipment damage, the secondary must always be short-circuited or connected to a burden.
Unfortunately, equipment connected (e.g. meters) to CTs still need to be serviced or replaced if faults occur. How then do we disconnect or test this equipment?
A solution for this problem is to provide a terminal block that allows for the testing and disconnecting of equipment whilst still leaving the CT short-circuited.
Now available from NHP Electrical Engineering Products is a new range of test/disconnect terminals from WAGO, that have purposely been developed to overcome these types of problems.
When using the new Series 282 test/disconnect terminals from WAGO, the possibility of damage to the CT is reduced even further. Clever and simple circuit jumpers, switches and bridges have been developed to perform the short circuit function on the CT.
The new test/disconnect terminals have the Cage Clamp connection technology. The use of solid, stranded and fine stranded conductors and conductors fitted with a ferrule can be terminated (0.2mm² to 6mm²).
The terminals are also fitted with 4mm touchproof test plugs.