Like most organisations we use cookies on our site, these allow us to improve your experience on our site, provides us with measurement and analytical data, and allows us to make use of the latest digital marketing capabilities - if you want to know more about cookies and how you can control them see our cookie policy here, if you are happy for us to use cookies then please click the button opposite.

ISS Calibration Card

The ISS Calibration Card, check your equipment is within range using a precisely defined set of values printed in to this handy card. It even doubles as a key ring so it's always ready to use.

Next Day Delivery (subject to availability)

£19.95 excluding VAT £23.94 including VAT @ 20% Regular Price: £36.00
  • Compatible with all installation and PAT testers
  • Earth Continuity Verification
  • Insulation Resistance Verification
  • 5 Calibration Points
  • 30DayMoneyBack
  • Description
  • Resources
  • Delivery

The ISS Calibration Check Card


Does the calibration of YOUR meter check out?

A verification unit is a necessary tool required by all tradesman working with electrics both in domestic and commercial environments.

The CalCard verification unit utilises a specific fixed range of resistance values, through which the ongoing accuracy and operation of test instruments between calibration periods can be verified.

This verification process is one of the mandatory requirements for meeting acceptable standards for all tradesman working in electrical environments. In the UK it is deemed one of the requirements to demonstrate “competence” of the tradesman by all inspectorates and the Health and Safety Executive.

What makes the national award winning CalCard the most popular choice with tradesmen and inspectorates is not just its size and affordability, but more importantly the ability to verify both the instrument and probes together.

The CalCard is one of the most affordable pieces of test equipment to meet compliance requirements.


*If you've already purchased your Cal Card and you're looking for our easy to follow setup guide, please click the image below.


Cal Card Setup


Once you've set up your CalCard, you can grab our handy CalCard Record Sheet and RCD Record Sheet to log your recordings.


Cal Card Record Sheet            RCD Record Sheet


What has made the CalCard the most popular choice for Electricians?

The CalCard satisfies all appointed inspectorates, British and European standards and HSE requirements with regard to instrument continuity and insulation verification, reflected in the recommendations from all inspectorates and governing bodies.

There are over 15,000 CalCards in use in the UK by End Users, Suppliers, Distributors, Training and Calibration Companies.

This successful and innovative product when first introduced presented a new radical approach to the then large and expensive “Box” solutions. However after winning three national major electrical awards, followed by ELECSA and NICEIC endorsement with re-badging the CalCard has gained an excellent unchallenged reputation.

Simply search CalCard Forum to read some of the independent reviews.


Handy & Compact

Yes it really is credit card sized but more robust and not as flimsy. Manufactured in a tough resilient very strong multi-layered glass fibre construction 1.6mm thick. Incorporating a hole for the included key ring.

  • Small enough to be stored with the instrument or even in your wallet.
  • There when you need it
  • Not lost in a toolbox or van
  • Built tough for the engineering environment
  • Integral Keyring for attachment to the instrument?

Improved Design

Test instrument contact is made through specifically constructed gold plated recessed touch pads.

Other Checkboxes and verification tools incorporate 4mm sockets, these not only limit the range of instrument but also require the removal of the instrument probes and clips to enable testing.

The CalCard works with all instruments and with whatever probes are connected to the instrument.

  • Verified measurements include the instrument probes
  • Recessed pads enable probe location
  • Reliable, quick and repeatable
  • Universal interface for all makes of instrument
  • CalCard is the only checkbox that verifies the instrument and the probes together

An integral part of compliance is that users record their periodical measurements against an identifiable check source. These records then demonstrate to an inspector that users are performing the verification task.

This operation is simplified on the CalCard by the inclusion of an identification serial number and provision of base value recording grid on the rear of the CalCard.

These are then sealed with a protective covering providing an indelible record for inspectorates.

  • Convenience for comparisons
  • Traceable reference standards
  • Indelible for inspector’s authentication
  • Free downloadable record sheets*

    *Please see our Resources section 

The Cal Card is Recommended/Endorsed by the following industy bodies


Endorsements Complete




Standard FREE 3-5 Day Courier Delivery – UK Mainland only - Zones A & B
Included in the price for all orders over £40.00 (exc vat). Sent using express courier, delivered within 3-5 working days from the date of your order, subject to availability.

Standard 1-2 Day Express Courier Delivery – UK Mainland only - Zones A & B
£4.50 for all all orders under £40.00 (exc vat). Sent by express courier, delivered within 1-2 working days from the date of your order, subject to availability.

Express Courier 1-2 Day Delivery – UK Mainland only - Zones A & B
£4.50 select at the checkout. Sent using express courier.

Next Day Delivery – UK Mainland only - Zones A & B
£8.00 select at the checkout. Sent using express courier, orders must be placed before 3pm for next day delivery, subject to availability.

Saturday Pre 12am - UK Mainland only - Zones A & B
£15.00 select at the checkout. Sent using express courier, orders must be placed before 3pm for Saturday delivery.

Orders must be placed before 3pm for next day delivery and a telephone number supplied, subject to availability.
Please note that predicted delivery times are based on regular trading days Monday to Friday. Public holidays, bank holidays and weekends are outside the usual scope of our dispatch and therefore may incure additional days lead time to your order.

Orders requiring calibration. Whilst we take the greatest care to get all orders dispatched and delivered to you in the stated time frame, orders received late afternoon and requiring calibration may on occasion miss dispatch that day, according to the complexity of the calibration. Be assured they will ship on the next dispatch, this in most cases should not add more than 24 hours to you delivery.

Delivery Surcharges
Because of the high cost of carriage we need to apply a surcharge on all deliveries made in the following regions bringing the carriage charges to:

  • Zones A & B  - Mainland delivery rates apply. 
  • Zone C - Scottish Highlands. 
  • Zone D - Outer Hebrides, Orkney Isles, Shetland Isles, Isle of Man, Scilly Isles, and Channel Islands.
  • Zone E - Northern Ireland
  • Zone F - Republic of Ireland

New Postage Map Sept 2018> 

International delivery

International delivery charges are automatically added to your order at the checkout; you can also use the guide below for a guide on prices. For any questions regarding international deliveries please contact us at

If no shipping option is available to your selected country please call us on +44 (0) 1603 406 148 to purchase your items.