Never believe any certificates or declarations

04 Mar 2020

Never believe any certificates or declarations

Commercial-off-the-shelf (COTS) products, modules and components may be declared by their manufacturers as being compliant with safety standards or Directives, and may even have certificates of 3rd-party approval by global safety Agencies such as UL, TUV, etc.

But we should never rely on such declarations or certificates, we should always check, and – if necessary – retest, for a number of reasons.

Declarations by a manufacturer cut no ice in court. For example, CE-marking-related declarations exist solely for the purpose of avoiding national customs checks when goods travel between Member States in the European Union (EU), and when goods enter the EU from outside. They have no other legal purpose, and (in UK Law at least) have no legal standing as proof of anything, such as safety or compliance with standards.

System integrators who collect Declarations of Conformity on the COTS they purchase, are collecting paper garbage for no good reason.

Worse still, I once saw an EU Declaration of EMC Conformity for safety-critical airport equipment, that included a little footnote that warned that mains transients could cause the equipment’s processors to crash. A result of such malfunctions could have been passenger aircraft colliding on runways, but the manufacturer thought it would be OK to hide this vital information in a footnote.

3rd-party ‘Safety Approval’ certificates should always be suspect too, until they have been checked out. One issue is that they may contain what are sometimes called ‘Conditions of Acceptability’ – meaning they are only safe enough under certain specified conditions, but this is usually not evident from the Certificate’s first few pages. 

An example will help illustrate what I am talking about. A customer of mine purchased a special US-made mains power converter rated at a few kW, which was supplied as being fully UL Approved.

It was indeed fully UL Approved, but page seven of its Approval Certificate included a section called “Conditions of Acceptability”, and my customer was not at all pleased to read its warning that under certain overload conditions the power converter he had purchased could emit a foot-long jet of flame in any direction for up to a minute.

In fact, according to its Approval Certificate, it was only UL Approved when fitted in an enclosure capable of withstanding such flames without allowing anything outside to catch on fire!

My customer had not been informed by anyone, in advance of purchase, that such a flameproof enclosure was necessary. Of course, it was documented in the converter’s 100-page installation manual and in the UL Safety Approval Certificate, but not near the front of either, you had to read them both completely through, from front to back, to discover this important safety requirement.

Who has time to read complete installation manuals before choosing which COTS to purchase?
Well, in my experience this sort of thing is not uncommon, and is even more common when it comes to EMC installation requirements – so if we don’t want to risk very unpleasant surprises in our futures, we need to make the necessary time.

Another example: I have seen a type of mains connector specified by its manufacturer as rated at 250Vac 25Arms and ‘VDE Approved’ – but when I obtained and read a copy of its VDE Approval Certificate, I found that it only covered up to 120Vac and 16Arms. (When I subsequently asked a different connector manufacturer if their declared ratings matched their 3rd-party approved ratings – they were most offended! Some manufacturers are more conscientious than others.)

I am told that this is a typical trick for mains-rated capacitors. They have printing on them that says they are Class X or Y, gives their voltage rating and often a 3rd-Party Approval Mark too., but of course there is not enough room on the capacitor’s body for the numbers of the standards they have been 3rd-party approved to. I have been advised to always to check the Approval certificate itself, to see whether the standards listed were the relevant safety standards, or whether they were for something else entirely – such as the thickness and quality of the tin plating on their leads.

So, one take-home message in this blog is to never make any assumptions about 3rd-party approvals. Always read all certificates, assembly and installation documents very carefully indeed, looking for such surprises, before deciding which COTS or component to specify for your product.

Another reason for suspecting certificates of 3rd-party ‘Safety Approval’, is that they may be fake. We should always check with the supposed Approvals Body whether they actually did issue the certificate we were given by the people wanting us to buy their product.

A senior officer with the UK’s Health and Safety Executive once told me about a long-established and very well-known manufacturer of mains filter capacitors (amongst other things) who got fed up with paying Approval Body fees and decided to fake their capacitors’ 3rd-party safety approval certificates. After all, no-one knew how to make safe mains filter capacitors better than they did! Several major fires later, the resulting court proceedings and persuaded them that they had been wrong.

I know the manager of a New Zealand test lab who was almost arrested by the local police for giving a dangerous product a safety certificate. It turned out that the dangerous manufacturer had obtained a copy of a safety report his lab had done for a competitor’s product, and photoshopped it to appear to cover their untested and dangerous product.

According to EU Directives (and UK Laws) the manufacturer of a product is always totally responsible for the safety of their product. Even if it is assembled from other people’s products, modules or components which the manufacturer purchased with all of the necessary safety documentation and used “in good faith”.

The “used in good faith” argument cuts no ice in court.  Manufacturers are required to satisfy themselves (and, if necessary, the investigating authorities) that their products are safe enough, and this includes not taking the safety of anything they have used in their product for granted.

I will write more on the “used in good faith” myth in another blog, but in the meanwhile it means that we should never assume that any 3rd-party Approval Certificates are real. We should always check with the supposed issuing body whether they really did issue it.

Some Approvals Bodies publish their lists on the web to make checking easier, and whenever I’ve sent a copy to an Approvals Body to ask them if it is real, they have always been very helpful. (After all, by doing so, I’m helping them police their market and take down counterfeiters.)

A final point: ‘badging’ a product with our own company name makes us the manufacturer under EU Law, responsible for all legal compliance issues.

There is a thriving trade in cheap products purchased by the shipping container load, with blank spaces where the company name is to go. Most such ‘badgers’ know nothing about EU Directives or standards and assume that if their products kill people or burn down their homes or places of work, they can simply pass the blame on to their suppliers. They can’t, but unfortunately these product ‘badgers’ never seem to attend any of my training courses because they “know” that they don’t need to know. Their ignorance keeps them ignorant, putting us all at risk.

Surely, you are thinking, I must be going overboard in saying never take any supplier’s declarations or 3rd-party approval certificates at face value? Surely we can trust some suppliers? Well, take a look at these two news reports, out of many filed on this scandal at the time, and ask if there can be any suppliers anywhere who we should automatically trust:,

Take care, it’s like the Wild West out there! 

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