Let's say you run a company that designs and installs speaker systems for clients. You hear their requirements, look at their space, and then select the most appropriate consumer products for their needs, buy them and install them for them, leaving them with a complete system.

All of the speakers, amps, sounds systems, etc. were all CE certified, but you've just created a new system from them. Each system would be unique (as the customers requirements would each be unique.) Would each system like this require CE certification? It seems to me that the cost of the certification for each system would cost many times the amount of the systems themselves. This would render any kind of business specializing in customized hardware systems infeasible in the EU, but as far as I can tell this is how the law is applied.

See this similar question: CE certification of a system containing only ROHS and CE compliant parts

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    \$\begingroup\$ wouldn't the law be the same as when you plug a toaster into an electrical outlet, or when you plug external speakers into your TV? ... your question is more suited for law.stackexchange.com \$\endgroup\$
    – jsotola
    Commented Dec 9, 2022 at 16:37
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    \$\begingroup\$ Amplifiers naturally connect to speakers so, what is the issue? The CE installation instructions for the amplifier will cover the installation/connection of speakers for sure. Common sense should prevail here and, if you are concerned, speak to the amplifier supplier and buy goods from a reputable source with a recognized quality system. \$\endgroup\$
    – Andy aka
    Commented Dec 9, 2022 at 17:18
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    \$\begingroup\$ I'd say the answer comes down to depends. A component would have stated requirements that CE certification would take into account. Meet those requirements and everything should be fine. That accounts for customized installations. But the devil is in the details. Any combination may cause EMI or power issues. Make 1000's and separate CE may be required. \$\endgroup\$ Commented Dec 9, 2022 at 17:35
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    \$\begingroup\$ In the case of an electrician, this is exactly what they do. They buy and apply certified components, assembling them into unique situations (all of them are unique from each other), and so long as they follow NEC code (US, anyway) as well, then the resulting work product is considered correct by an insurance company and will be covered unless they find gross negligence or a home-owner has made modifications that don't meet code. Even that's not perfect as the insurance contract isn't air-tight. It's more about perception, to them, whether they pay or not. \$\endgroup\$
    – jonk
    Commented Dec 9, 2022 at 18:32
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    \$\begingroup\$ In your case, where a customer is almost expected to make changes later, I don't know what to imagine here. If you are a deep-pocket in the US anyway then you can be included in any situation where financial harm involving anything you touched is involved. In fact, technically, you could be included in a suit even if your work isn't involved. Just that your name is anywhere to be found related to some claim. (I've been served papers just for standing on a property for a half hour and merely looking at it. I never touched a thing.) So it's better to get an expert involved than guess. \$\endgroup\$
    – jonk
    Commented Dec 9, 2022 at 18:35

4 Answers 4


UL (CE?) is so non-engineers can do electrical work

The point of UL Listing is to say "there is a reasonable path by which a non-engineer can apply this product safely".

As such, it is important to define a scope of use - what you can use it for, and what you can't. (without being an engineer). That is defined in the instructions and labeling.

I'm not a product certification engineer in Europe, so I don't know that well how CE works when it works but I suspect it is the same. (it certainly doesn't work in North America; 99% of CE-labeled things in this country are fraudulent marks on unsafe products bought on Amazon Marketplace and made guess where).

Engineers can do what they want.

You see this all the time in the US National Electrical Code. They'll have rules, and then toss in an exception for sites under engineering supervision. I.E. where there are on-site engineers.

The engineer gets to look at the actual situation and apply skill and training to a correct solution. Backed by professional insurance and subject to license review or revocation if they screw up. This is how automotive assembly plants work; they don't send every built machine to UL for certification. The automaker's in-house engineers are expected to wear UL's hat for that purpose. (under pressure from OSHA and the company's risk management and ergonomics staff).

You are simply installing equipment according to labeling and instructions

As such you are operating under the UL/CE umbrella of already-approved uses. That is going to be the case for almost all audio equipment installations.

I don't see anything you'd do with custom AV systems / home theaters that would be other than that, unless you are free-styling some sort of AC power distribution in ways that is inconsistent with local Codes.


Probably not. CE applies only if you are putting a new product on the European market (as manufacturer or importer) for anyone to buy. If I understand your question correctly, your are only offering a service to put together a unique arrangement of already existing products.

And CE isn't a certification, either. It's a declaration of conformity with all applicable standards for the European market. Anyone can declare conformity for their product without testing anything.

Of course, you will get in trouble, if your product harmed someone and you cannot pull something out of your drawer that actually proves compliance (e. g. EMC tests, if applicable).


If you make a new system from parts that you sell as a whole to the consumer market, then you (or your boss) must guarantee its safety and compliance, which is done via e.g. the CE declaration in the manual and the label.

It is possible to build a bomb from CE parts, so the parts don't make the system safe.

Of course you can declare conformity without having had a test, or worse known your stuff doesn't comply. And many marketplaces will still sell it, but if you are ever sued over it, you better have an army of lawyers.


If the parts were meant to be used together by following audio standards etc, then your company is more of an end user than a manufacturer. However, any company selling (put on market) any electronic product is responsible to ensure that it conforms to relevant directives.

Now in case you do something like modifying the products, then you'll have to CE mark. Which can be done as self-certification, as long as you actually know which technical standards that apply and that the product confirms to them.

The perfect example would be when taking audio equipment designed for indoors use and mounting it outdoors. Then quite likely the LVD directives requirements regarding electrical safety and IP class apply, and you have added requirements that weren't placed on the original products.


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