Current transformers and voltage taps for energy measurement

Current transformers are used for measuring high currents. If you want to measure a 1000 ampere current (A) with an energy meter, the current must first be transformed down 200 times. Current transformers are used for this.

The ELEQ current transformers have different properties, suitable for a wide range of applications:

Compact, split core current transformers for a wide range of cable sizes
Suitable for low and medium voltage systems
Current transformer with a fused voltage tap
Current transformers for use in combination with a three-phase automatic switch

Voltage taps for busbar and DIN rail mounting

Voltage taps for busbar and DIN rail mounting are ideally suited for fast and safe measurements in existing installations. Both for temporary and permanent voltage measurements.

Variants of voltage taps:

Voltage taps for DIN rail mounting
Voltage taps for wire, with or without fuse

View current transformers in the webshop

Indirect level measurement with current transformers

Overview current transformers with conventional ../5A & ../1A output

Overview of conventional models of current transformers
Description	Compact transformer	Power sensor	Split core current transformer "click and go"					Rogowski
Type	RM27	VCT32	TQ30	TQ40-B	TQ40-C	TQ50-E	TQ50-L	Rogotrans	Rogo Coil

Transformer width	27 mm	32 mm	36 mm	48,8 mm	48,8 mm	66 mm	66 mm	22,5 mm
Transformation ratio
	35/1A	35/1A	60/1A	100/1A	200/1A	250/1A	250/1A	250/1A
	64/1A	64/1A	100/1A	150/1A	250/1A	300/1A	300/1A	500/1A
			150/1A		300/1A	400/1A*	400/1A*	1000/1A
			200/1A*		400/1A	500/1A*	500/1A*	2000/1A
			250/1A*		500/1A*	600/1A*	600/1A*	4000/1A
						750/1A*	750/1A*
						800/1A*	800/1A*
						1000/1A*	1000/1A*
Other specifications
Class	1	1	3/1*	1	1/0,5*	1/0,5*	1/0,5*	0,5
Max. cable diameter	7,5 mm		18 mm	18 mm	28 mm	42 mm	2 x 42 mm		70 mm	175 mm	300 mm
Max. rail dimensions									70 mm	175 mm	300 mm
Connection of secondary measuring line	Connector 1,5 mm²	Connector 1,5 mm²	3 m / 0,5 mm²	3 m / 0,5 mm²	3 m / 0,5 mm²	5 m / 0,5 mm²	5 m / 0,5 mm²		3 m	3 m	3 m
Item numbers
	RM27	VCT32	TQ30	TQ40-B	TQ40-C	TQ50-E	TQ50-L	JA900315	JA900249	JA900250	JA900251

Measuring with low-power current transformers

In addition to conventional current transformers, it is also possible to opt for low power current transformers. Low power current transformers are safer and easier to use than standard current transformers. They contain an internal resistor that prevents the occurrence of high voltages, thereby reducing the risk of sparking and making a short-circuit block unnecessary. Additionally, they provide an output of 333mV, making the installation safer.

Beyond the safety benefits, low power current transformers offer several other advantages. They allow the use of thinner and longer cables without affecting the measurement results. Furthermore, the use of connectors is possible, and they are cheaper and more compact.

Specialist low power analysers or current measurement modules are required for connecting low power current transformers. Below is a clear overview of the different low power current transformers and the analysers or current measurement modules they can be connected to.

Overview low power current transformers with ../333mV output

Low power current transformers for: UMG 96-PQ-L-LP and 800-CT8-LP*
Series	CT		CT-BSC		CT-SC

Transformation ratio
	50A/333mV	250A/333mV	600A/333mV	1200A/333mV	20A/333mV	50A/333mV	75A/333mV	100A/333mV	100A/333mV	400A/333mV
	100A/333mV	-	-	2500A/333mV	-	75A/333mV	-	-	200A/333mV	600A/333mV
	-	-	-	-	-	-	-	-	250A/333mV	-
Other specifications
Type of current transformer	Non-divisible		Divisible		Divisible
Secondary measurement lead connection	5 meter fixed		Screw connection		5 meter fixed
Max. cable diameter (mm)	0.9 (50A) 12.3 (100A)	19.3	21 x 51	50 x 90 (1200A) 80 x 120 (2500A)	6.1	9.5	12	16	23.3	35.3

* The 800-CT8-LP current measurement module is suitable for connection to the main modules of the UMG 800 series.

*Low power current transformers for: 800-CT24 current measurement module**
Series	CT24-SC

Transformation ratio
	50A/333mV	50A/333mV	100A/333mV	100A/333mV
	75A/333mV	75A/333mV	-	-
Other specifications
Type of current transformer	Divisible
Secondary measurement lead connection	25cm with molex connector	200cm with molex connector	25cm with molex connector	200cm with molex connector
Max. cable diameter (mm)	10.2	10.2	12.5	12.5

* The 800-CT24 current measurement module is suitable for connection to the main modules of the UMG 800 series. To connect the 800-CT24 to a UMG 800 main module, the 800-CON-RJ45 communication module is required.

Current transformer for use in combination with three-phase switch (rm27)

Current measurement at a lower level is necessary in many installations. Relatively low values are measured at this low level and the available space is minimal. In addition, the measurements must meet high accuracy (minimum class 1).

Most compact IEC transformer for accurate current measurement

The compact RM27 current transformer is the smallest current transformer on the market and has been specially designed for use in combination with digital measuring systems. The small current transformer is also suitable for use on a three-phase automatic switch with a 17.5 mm distance between the phases. The RM27 is supplied with a connector with terminal technology for mounting on secondary connections. Optionally, mounting on a DIN rail or clip for screw mounting is possible.

Features RM27 compact current transformer:

Ideal for detailed current measurements at level 4, where no direct energy meters can be used
Easy to integrate with the Wago Picomax connector
Meets the requirements of IEC61869-2
Ideal for detailed flow measurements up to automatic level
Primary lead-through opening suitable for cable Ø7.5 mm
Super compact, suitable for use on a 3-phase machine
Accuracy class 1, suitable for energy monitoring
Output power tailored to modern meters such as Janitza
Available in 35/1A and 64/1A transfer ratios
Also suitable for mounting on a DIN rail with optional adaptor

View RM27 compact current transformer in the webshop

Current transformer with a fused voltage tap (vct)

To measure power, the voltage and current values of each phase must be known. The power sensor (VCT) from ELEQ combines three functions in one product: the fused voltage tap, the current transformer and the connection terminal.

One product for voltage and current measurements

The VCT32 from ELEQ combines accurate current measurement and fused voltage branching and a 16mm² connection terminal in one product. By applying the VCT32, the chance of connection errors is minimised, higher safety requirements are met, less installation space is required and the costs for installation are reduced.

Characteristics of current transformer with fused connection (VCT32):

Minimising connection errors through three-in-one product
To be mounted on DIN rail or on the mounting plate
Easy to install
Specifically developed for power measurements up to 64A
Including specialist short-circuit proof (70kA) SIBA fuse (2A)
Available in transfer ratios 32 / 1A and 64 / 1A
Accuracy class 1 for the current transformer

View current transfer with fuse connection in the webshop

Current transfer with fuse connection - ELEQ

Compact split core current transformer for cables

Quickly perform accurate flow measurements in small spaces or existing installations with the TQ line split core current transformers from ELEQ.

Simple and efficient flow measurement

Current transformers are easy to install due to the compact design, the hinge construction, and the supplied cable tie around the transformer to mount the insulated conductor. The long color-coded secondary connections ensure that the transformer is seamlessly connected to the energy meter.

The specified power rating applies at the end of the secondary branches and is adjusted to modern energy measurement devices such as the Janitza meters. The transformers meet the requirements of IEC61869-2, which guarantees accuracy.

Features of the TQ series split core current transformers:

Compact and hinged for easy installation
Suitable for the insulated conductor
Suitable for energy measurement
Color-coded connections simplify assembly
Available in different variants and transfer ratios (see table)

View TQ series current transformers in the webshop

Insured voltage cover for rail mounting

To create a safe and simple voltage branch in your distribution system, the secured voltage branch UAK and ZK4 from ELEQ is the suitable solution. Thanks to the fused voltage branch, both the measuring line and the object to be connected are protected via the integrated fuse. The branch on the voltage-bearing rail is also immediately secured. Both series of voltage branches have a high short-circuit resistance, which makes them suitable for all types of installation cabinets with voltage-bearing rails.

Features UAK and ZK4 fused voltage tap:

Safe branching of voltage for measuring purposes
All models with fuse directly on rail
Extremely suitable for use in combination with power meters
Simple and safe assembly
Suitable for a fuse with short-circuit resistance up to and including 70kA

View busbar terminals for voltage tension in the webshop

Insured voltage cover for rail mounting - ELEQ

Voltage tap - Phase terminal with fuse - ELEQ

Voltage cover for cable: with or without fuse (uad)

Measuring branch fused voltage from an isolated state? Then the UAD voltage tap is the suitable solution. The fuse of the voltage tap is mounted directly on the primary conductor. This ensures optimum safety. The UAD from ELEQ is a fast and safe way for measurement in existing installations.

Features of the UAD voltage branch for cable:

Safe branching of voltage for measuring purposes
Simple and safe assembly
Suitable for fuse with short-circuit resistance up to and including 70kA
Resistant to temperatures from + 5°C to + 55°C
Protection class IP20

View voltage shaft clamps without fuse in the webshop