Unfortunately there are no shortcuts in the EU for custom products. In the United States and Canada, there is a "Field Labeling" program that provides a limited product certification review to UL and CSA standards for custom products. However, in the European Union (EU), there is no limited review method to obtaining the CE mark. There is also no CE field review option for imported equipment since the product won't even make it through EU customs if it doesn't bear the CE mark.
In general, you need to follow the same process as if you were making a high volume production product. If the product cost warrants it, a full CE review is your best approach. However, in cases where conducting a full CE review isn't possible, there may be ways to limit the extent of the CE Compliance Review.
Options: Do you need to meet all applicable Directives? Could you limit the number of Directives that you apply to the custom product? Are there any exceptions that could be applied to the custom product?
Options: Does the product comply with a standard not on the Directive Standard List? How does that standard compare to the most appropriate standard for your product on the Directive Standard List? Could you use a compliance report for a standard not on the Directive Standard List to declare compliance?
Options: Could you declare compliance with a Directive or Standard without testing? For many Directives, non-test methods to verify compliance are permitted.
Options: Could you leverage the fact that you are only making a single unit to reduce the risk level of the product and the requirements that apply? Most standards anticipate a product being produced in quantity, thereby increasing the variety of users/user experiences that increase the likelihood that an injury will eventually occur.
Options: Do you have any similar products that are CE compliant? Could we use the Technical Construction File for a similar product to help reduce the scope of the CE review on the custom product?