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Safety lettering on a product


We manufacture a number of consumer products for the European market. They generally include RFID and probably BlueTooth and so are all tested against the RED for EMC and RF and EN62368 for safety.

I am having a problem with finding a definitive definition of what "legible" means when ascribed to safety and compliance information. Its easy to find the correct heights for the compliance marks but I cannot find a definitive minimum text size for other compliance information such as the company address and or instructional safeguards on the product rating label. This information is generally moulded directly into the casing and so is hard to change once it has been done.

I know the FCC part 15 sets down a minimum point size of 4 point but I cannot find any real guidance from the EU standards other than "legible" and "readily discernible under normal lighting conditions".

Can anyone point me at any guidance for the minimum acceptable character height or point size as we are needing to shoehorn in some information onto an existing product rating label space

Any assistance would be most welcome

Hello Chris.

This is a controversial topic, because as you have well been stated, IEC 62368-1 does not specify the term "readable".

The controversial increases, when the test says "without appreciate or excessive force", so what is excessive force and what not?

Maybe you could get some guidance on any other IEC standards. For example, medical standard IEC 60601 -1 had defined a clearly test on this topic on beginning on chapter 7. Some parts 2 of IEC 60335-1 standard state some height requirements on the size of user manual letter warnings too.

Best regards.
Not really as it appears mainly to be relevant to printed documents.

the minimum size in this document is 8 or 9 point which for a moulded rating plate would be quite large. The FCC reg's refer to a minimum size of 4 point which to be honest is probably a bit small for legibility but at least it is a number.

As standard we have tended to use 5 or 6 point text on most of our products but I am trying to find out where the limits are as we have a couple of smaller units coming through the system and need to understand what the rules are


Quite Involved in Discussions
I've not come across anything definitive for equipment falling under the RED. Assuming the device isn't directly connected to the mains, you don't need much safety information on the actual product, so much of it can go on accompanying documentation as per RED article 10.
There is no definition or guidance of "where the size or nature of the radio equipment does not allow it" so you will have to make a judgement call and be prepared to defend it if required.
Whilst "please sir, but they only do this" isn't a defence in court, looking at markings on similar sized products from global manufacturers can provide guidance on what it likely to be acceptable
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