Recently Added Items
Cart 0
Page Search:
1 - 2
Product Search
Search catalogue ...
Search term found on 0 pages...

Latest News / KATKO Safety Switches

KATKO Safety Switches

KATKO Safety Switches

Basic Information and Ordering Guide

ACDC Dynamics is proud to supply a quality brand like Katko. With its amazing selection of safety switches, we are perfectly positioned to meet any of your requirements. We would like to tell you a bit more information about the Katko switches available from ACDC Dynamics.


KATKO Enclosed Isolators are mechanical Load Break Switches that are designed to safely isolate low voltage electrical machine loads from the grid during installation or service. People refer to their products as “life insurance for the maintenance worker”. Therefore, they are dedicated to creating the safest products on the market to ensure the safety and security of the user. In order to live up to their mission of manufacturing the safest and most reliable products, KATKO invests a lot of time and financial resources into R&D and PPE (property, plant and equipment) to assure the highest level of quality for their products.
KATKO’s key design principals in R&D are simplicity and durability. Careful selection of the best raw materials, and continuous open discussion with our feedback loop (customers and partners and selected installers) creates the KATKO experience.


Since their products play an important role in securing overall safety of users, KATKO care greatly about user experience of their products – enclosed isolators are designed to be safe, easy to install and to use. The isolators are typically positioned in the immediate vicinity of a machine, so that the user can reliably isolate the machine off the grid when needed. The intuitively and easily lockable handles form the foundation for safe maintenance work – KATKO front operated products can be locked in OFF-position with three individual padlocks, allowing three separate maintenance workers to insure themselves.
The front-operated isolators come with a door interlock system, and defeat mechanism. The door interlock system prevents the cover of the switch from being unintentionally removed when the switch is in the ON-position, but also prevents it from being removed when the switch is in the “padlocked OFF-position”. The defeat mechanism allows for the removal of the cover with an additional tool (e.g. a screw driver) when needed. However, when the switch is in “padlocked OFF” position the cover can’t be removed without damaging the product.
These features combined with selection of the right product for prevailing operating environment grants the most pleasant user experience possible.


The utilization categories are defined by the IEC standards and indicate the type of electrical load and duty cycle of the loads to ease selection of contactors and relays. The categories associated with KATKO products are:

AC-20: Connecting and disconnecting under no-load
AC-21:Switching of resistive loads, including moderate overloads
AC-22:Switching of mixed loads, inductive and resistive loads including moderate overloads (applicable when used as a main switch of a switchboard)
AC-23: Switching of motor loads or other highly inductive loads (applicable when used as an isolator for a machine or a motor)

The category defines the products current ratings in the table (1.1 or 1.2).

In the “Selection Table” you will find the utilization categories AC-22 and AC-23 for 415V, as these are the most commonly used categories. However, the 500V and the 690V ratings can be found in the KATKO product catalogue.

Most of the competitors offer products with only AC-20 and AC-21 ratings, which are then de-rated for other utilization categories.


KATKO provides a large range of 1,2,3,4,6 and 8 pole switches from 16-1600A, as well as changeover versions and switch fuses from 16-630A.

All KATKO Switches are Load Break Switches, not no-load isolators (AC-20). KATKO switches have ratings of AC-21, AC-22 and AC-23 for each switch.

As AC-22 is the most commonly used when talking about switches, it is worth noting that this utilization category is only applicable when the switch is used as the main switch of a switchboard (IEC/EN 61439 – distribution boards directive). KATKO uses this rating as the basis for parts numbering. For example, the KEM 316 is a 3-pole 16A switch with an AC-22 rating. The AC-21 rating of KEM 316 is 25A, and most of the competitors use code 325 for a corresponding switch.

The AC-23 rating of KATKO switches ensures that the switch can make (withstand) 10 times the rated operational current and break 8 times the full-load motor current, so the switch can break a stalled motor load. Therefore, this utilization category is applicable when a switch is used as an isolator for a motor or a machine (IEC/EN 60204 – machinery directive).

Use the AC-23 ratings when the solution is to be used with motors or machines.


The products are installed in various environments. This has led to developing a wide enclosure range consisting of materials with different levels of protection to ensure the product’s long life cycle. The end installation environment of the solution determines the enclosure material. All KATKO enclosures range from IP65 to IP67 (refer to product catalogue). KATKO uses 4 main groups of materials in its isolator range: Plastic (ABS & Polycarbonate), Aluminium, Sheet Steel and Stainless Steel (AISI 316 & AISI 304), choosing from these materials provides the customer the best possible protection of the switch from environmental elements. KATKO enclosed switches/isolators have a range of -40°C to +80°C at operating temperature, with the exemption of KATKO fire-rated solutions that can withstand 300°C for 2 hours. Below you will find a brief explanation of each enclosures material and their use.

Plastic (M) up to 630A: Polycarbonate enclosure is usually the “go to” enclosure, as its versatile and has a long life expectancy in moderate conditions.
Aluminium (A) up to 250A: Aluminium enclosures are excellent for hard weather conditions, good resistance against many chemicals and wide operating temperature. Recommended enclosure for outside use in harsh climates.
Sheet steel (T) up to 1600A: Sheet steel enclosures have a good corrosion resistance, excellent insulating properties, and are also available in larger sizes than the aluminium enclosure, (available up to 1600A solutions).
Stainless steel (R) up to 1600A: Stainless steel enclosures offer superior protection; they are specifically designed for Food & Beverage and Mining industries. KATKO offers two different ranges of the Stainless Steel Enclosure (AISI316). One range (KER) comes with a lockable polycarbonate handle, and the other range (KER___R) comes with a robust “easy to clean” stainless steel handle. The latter of which is also available with angled roof and hygienic sealant (KER___RS).

On top of this, KATKO also have an EMC-protected enclosed switch/isolator range (16A-800A) supplied with the appropriate EN 55011 compliant EMC cable glands. They are typically used in hospitals and other environments that require protection against electromagnetic disturbance.


All KATKO switches are tested by independent, accredited testing institutions for compliance with the relative standards (testing certificates can be provided to the customer upon request). All Katko switches are designed to comply with both national and international standards. We also have third-party certificates complying with IEC, NEMA, CCC, EAC, KEMA, PCT CH01, RINA, CE, and more.

All KATKO products comply with the IEC standards for low-voltage switchgear and control gear (60947-series). KATKO has a range of UL-listed products, and products with the following: certificates: Rina, KEMA, CE, EAC, EMC, EX, CCC, BBJ.

These accredited testing institutions perform annual, semiannual or once every two years full factory audits at KATKO facilities, they re-evaluate the premises and processes necessary for continuity of the certificates.

Furthermore, KATKO performs 100% in-house testing to all its products in order to maintain a high level of quality.


In order to specify the right solution for customer needs, the following information needs to be gathered:

1. Knowledge of applicable customer segment the product is going to be used in, as this is closely linked to the installation environment and the IP-class of the solution
2. The utilization category of the application: AC-20, AC-21, AC-22, AC-23 (determines which ratings are used in specifying the solution)
3. Power / current (kW/A) of the application, as this determines what switch is to be used (Example AC-23 30kW: 400V motor: 80A switch), more info about ratings in the appendix 1
4. Size and type of cables determines the number of poles required and the size of the enclosure (and cable gland) to be used, directive information in the appendix 2
5. Need for auxiliary contacts (how many are needed)
6. The installation environment (determines the material of the enclosure)

This table excludes 6 and 8 Pole options. If interested, please refer to the KATKO product catalogue

Cable connectors / entries – KATKO products over 200 A come with a tag terminal. Cable connectors and entries are needed for the installation, these are available on demand (product catalogue)

Stainless Steel Enclosed Isolators also available with a stainless steel handle (R – at the end of the product code) and stainless steel handle and an angled top (RS – at the end of the product code).

Dimensions (external) in mm (width * height * depth)

For mounting dimensions refer to KATKO product catalogue

IP-ratings only hold true when appropriate cable gland is used

Related Products