CVTs approval to international standards


There is now a new international specification which relates directly to constant voltage transformers. BS EN 61558-2-12. Advance transformers meet all relevant standards, but in this case since the standard just strung together a lot of best practise, AEL CVTs had exceeded the specification for decades.

A specification exists for UPS products BS EN 50091-93 but this is little overlap.

Existing approvals

The CIT range up to 1500VA has been approved to NEMKO NEK-EN 60742 and SEMKO 115X.

The Smartstab conditioners rated 100-1000VA have been designed to meet SEMKO 115X.

Potential approvals


Some of the GT series were approved by UL but we have allowed this to lapse through lack of sales to interested parties.

We also used to have an insulation system approval but this has been allowed to lapse for the same reason.

We have no technical problems with meeting relevant UL specifications but the commercial cost of upkeep is uneconomic.

Customers who must have approval for their equipment may request that we design for the standard required.

When the equipment comes up for overall approval we provide constructional data to facilitate the approval process of our component.

Our customer remains responsible for the commercial upkeep of the approval as required.


Generally as per UL.


We expect to comply with all the European Directives as and when applicable.

By getting certification to EN 60950 or EN 60742 we hope to have product safety acceptable for the USA and Canada as well as EEC member countries.

A generic Certificate of Conformance for CE requirements is available as HB 57.


We use the self certification method for most OEM items.

Our product is particularly suitable for filtering out mains conducted noise on old equipment.


We use the self certification method for most OEM items.

There are a number of transformer related specifications. There are also relevant specifications in the office equipment and information technology areas.

Where necessary we can review any one of our units to a particular specification.

We have supplied a number of different designs to meet various specifications as components and are happy to do this where customers need it.

Component Approvals

We maintain a computer file of international specifications held by various components which we use.

This is integrated with our Bill of Materials software and can be used to print a list of approved items in any of our products.

A file of master copies of component approval certificates is maintained.


We would be pleased to review this document with any interested party.