Terminal blocks test CT and VT secondary circuits.

CTs and VTs isolate a primary power feed from a secondary circuit, permit grounding of the secondary circuit, and step-down the current or voltage to an appropriate level for measurement.

Terminal blocks are then used as the termination points for instrument loops on the secondary circuit.

Panel builders have traditionally incorporated barrier-type terminal blocks in CT circuits—but these are challenging to access, require proper tools, and take time for backplane mounting and screw-down wire terminations.

Additionally, there is always the danger of under-torqueing and loose wiring connections, or over-torqueing and stripped screw threads.

Dinkle’s DPT DIN rail series terminal blocks address these issues by providing easier access, DIN rail mounting with no tools required, and push-in design to ensure secure wiring connection while reducing time and tools required for termination.

The DPTD6 model block also provides direct-testing technology, enabling a user to test the circuit current without undoing any wired connections. To perform direct-test for a single or three-phase circuit, the user switches a lever on the terminal block to disconnect a de-energised circuit.

The user then places a current-measuring device across the block at its test points using either 4mm test probes or securely fastened 2.3mm test plugs.

The DPTL6 model version is similar to the DPTD6 but without a disconnect lever for testing.

Both blocks are UL rated up to 30 amps at 600 VAC. The blocks are DIN rail mountable and measure 8mm in width by 103.2mm in height by 50-57.5mm in depth (depending on DIN rail depth), allowing for easier installation and space saving compared with traditional barrier-type terminal blocks.

These push-in style blocks accommodate wire sizes from AWG20 to AWG8, and also feature plug-in slots for bridges (jumpers), providing reliable continuity between any combination of blocks on the same DIN rail.

They are completely touch-safe—back of hand and finger protection—and operate at temperatures from -40°C (-40°F) to 120°C (248°F).

Users can employ these DPT series blocks to safely disconnect secondary circuits between measuring instruments and safety equipment in CT shorting and other applications. A safe disconnect can be achieved by placing the block in front of the measurement instrument.

Dinkle provides a complete product line of DIN rail terminal blocks to complement the DPT series, including but not limited to power distribution, sensor/actuator, diode embedded, and pluggable fuse blocks. Their products carry safety approvals including UL, CUL, CSA, VDE, and GB. The material used for manufacturing is compliant with RoHS and REACH environment standards set by EU.