[c-c-c-c-c]

Yes thats evidently clear but you usually don’t need external accreditation if you do in house testing and keep a compliance file for the product, this applies for both the US and EU.

In-house emc testing is quite fun and you dont need much more than a spectrum analyzer, antenna and E/H-field probes.

[adrian_b]

In-house EMC testing is practically always required before you go to an external lab, unless you want to waste a lot of money by discovering at the lab that your device cannot be certified.

When done just for this purpose, it can be done much more cheaply than at a proper lab, because you do not need very accurate results.

[chambertime]

Well there's a bit more to it than that. It depends on if you're making an intentional radiator. I have another flow chart on the site that helps you figure out if you need to send your device to a testing lab or not.