Howard Butler Ltd


Howard Butler Ltd has been manufacturing panel meters, current transformers, relays, transducers and associated products in our UK factory for over 85 years.

Howard Butler Ltd has ISO 9001:2008 approval with a constantly reviewed quality policy. This ensures that through our  vigilance, control, design methods and accountability throughout all stages of design and manufacture quality is designed and built into our products. Our in-house design engineers are able to work with customers to provide custom solutions where our standard product range is not applicable. Our policy is one of continuous improvement, therefore the HOBUT range is regularly added to with new products, mostly designed to IEC, BS, or DIN specifications.

We hold extensive stocks of vital components to ensure quick delivery of both standard and special
products. Customer satisfaction is central to the aims of Howard Butler Ltd, with our fully integrated
computer system closely controlling orders, enquiries and stock.

Current Transformers

Howard Butler Ltd is the largest UK manufacturer of Current Transformers. We have been manufacturing in England for 90 years. We offer standard Current Transformers as well as Current Transformers to customer designs in plastic injection mouldings or cast resin and ring types. Our worldwide sourcing of raw material ensures our products are amongst the most competitive in the world.

Toroidal ring type current transformer: Suitable for measuring or protective applications with accuracies of class 0.2, 0.5, 1, 3, 5P10, 10P10 etc.

Resin cast rectangular current transformer: The range is suitable for metering, protective and class X types and is particularly suited to high current and large busbars, where the rectangular style allows for easy mounting of the current transformer.

Moulded case rectangular CT's: For mounting on vertical busbars and transforming various primary current into 5A or 1A standard secondary.

Click here for a guide to choosing the right transformer for your application.

Current Transformers

Panel Meters

Analogue  panel meters:
90 Degree panel meters: Din panel meters with standard 90 degree scales. Used throughout the World, these meters can have Moving Iron or Moving Coil movements for A.C. or D.C. use. They are available in 48 x 48mm, 72 x 72mm or96 x 96mm case sizes to fit standard square panel cut-outs

240 Degree panel meters: Used widely in the panel building industry where a standard sized DIN sized meter is required with a long scale for easy reading.

Prodin range panel meter: Used widely in the panel building industry where a DIN product with a horizontal scale is required. Round barrel allows easy installation without special tools.

R88 panel meters: Used widely in the panel building, welding and battery charger industry, where a round barrelled instrument is required to fit into a standard 64mm diameter panel cut-out

Digital panel meters:
With the combination of mA input M300-AD1 and the M100 series Power transducers, parameters such as kW, kV, Ar etc can be measured and displayed. Customer adjustment of botjh "ZERO" and "SPAN" is permissible via potentiometers, accessible from the rear of the product.

Panel Meters

Multifunction Meters

M850 Multi-function Meters: The new range of Hobut multifunction panel meters feature 96 x 96mm sizes complete with unique blue LED screen, which can be seen in direct sunlight. The range is easy to use, features user-programmable CT & VT ratios, and can be used on any single or 3 phase system with any input voltage without re-programming.

Standard Functions:

Phase Voltage (V)Neutral current measurement.
Phase to Neutral Voltage (V)Reactive Energy(VArh)
Phase Current (I)Power Factor (PF)
Frequency (Hz)Instantaneous Amp Demand
Active Power (W)Instantaneous Watt Demand
Active Energy (kWh)Instantaneous VA Demand
Reactive Power (VAr)Maximum Amp Demand
Apparent Power (VA)Maximum Watt Demand
 Maximum VA demand

MULTIDIN Multi-function Meters: The MULTIDIN range of multi-function panel meter features 96 x 96mm sizes complete with backlit LCD or LED screen. The range is easy to use and features user programmable CT & VT ratios.
The MULTIDIN range is a cost effective replacement for the traditional panel meter and is suitable for low, medium and high voltage control panels, gensets, building management systems, power management and more.

All models feature the following user-programmable functions.

  • Current Transformer Ratio
  • Voltage Transformer Ratio
  • Baud Rate
  • Custom Screen (LCD Models only)
  • Parity
  • Stops
  • RS485 address 1-247
  • Security code access for programming
Multifunction Meters

Earth Leakage Relays

Our variable earth leakage relays are supplied with compact 35mm din rail mounting cases and are designed for use on 3 phase electrical systems. They are used to monitor earth leakage and trigger the appropriate relay at a preset current. They are often purchased with our core balance current transformers.

All models feature the following user-programmable functions.

  • Current Transformer Ratio
  • Voltage Transformer Ratio
  • Baud Rate, parity, stops.
  • AC or DC AUX
  • Single or 3 phase system
  • Input voltage range 28-570V
  • RS485 address, 1-247
  • Security code access for programming.
Earth Leakage Relays


Our highly accurate manganin shunts are used for measuring D.C current by connecting them to moving coil panel meters or digital meters. When a current is passed through the shunt a proportional millivolt output is produced.

Shunts can also be used in  control devices such as power supplies and battery chargers for overload protection. We have a wide range of brass ended, plate type, wire type and custom shunts suitable for currents from 300 mA up to 10,000 Amps. Our in house engineers can work with customers to design special shunts for their specific application if the standard range does not cover their needs.

Standard Brass ended, Compact brass ended, Plate,  wire and special shunts.

Special shunts: Highly accurate manganin resistance d.c shunts. When a current is passed through the shunt a proportional millivolt output is produced.The products detailed in this production are our standard range, but for quantity orders, HOBUT engineers will be pleased to work with customers to design individual shunts to their specifications. 


Protection Relays

Our protection relays are DIN rail mounting and designed for use in single or three phase electrical applications. They are for over protection, under protection and combined under & over protection available in AC current AC voltage & frequency versions. Millivolt trip, DC voltage trip, Reverse Power, Phase sequence & Phase balance relays also available in our extensive range of protection relays.

For more information and specifications please visit our website.

Protection Relays

Other Products

The entire range of HOBUT products can be viewed at


Other Products
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