This Guidance Note Must Be Used in Its Entirety

USCEL

TECHNICAL GUIDANCE NOTE:

This Guidance Note must be used in its entirety.

The guideline as stated must be considered in the ISSUE NO: 011

context of the issue, rationale, assumptions and the

reference documents.

FINAL ISSUE DATE: February 25, 1997

No responsibility or liability can be accepted by the United States Council of EMC Laboratories (USCEL), its secretariat or any of its officers or members and their companies for the contents, specifications and/or advice referred to or contained in this Technical Memorandum and/or for any action taken as a result of information contained in this Technical Memorandum.

NOTE THAT:

1. The Council is not, by supplying this Technical Memorandum, providing professional advice or guidance to any specific party on any specific matter and no legal relationship is created by the provision of this Technical Memorandum.

2. Parties should consult their own professional advisors in this regard.

ISSUE AS SUBMITTED:

1.   Is EFT testing required for devices that do not connect to the AC mains but received its power from a CE marked computer test bed that connects to AC mains?

2.   If the EFT test is performed once on the computer test bed with an internal device operating, and the EFT did not affect the performance of the EUT, does testing need to be performed with different versions of internal EUT’s installed or does the previous test demonstrate compliance for all internal devices?

RATIONALE AND ASSUMPTION IN DEVELOPING GUIDELINE:

Note. EN50082-1 1992 table 3 lists tests required for DC input and output power ports, table 4 lists the tests required for AC input and output ports. Conversely, tables 4 and 5 of EN61000-4-4 list the DC and AC power ports. It is recommended that internal devices use the benefit of additional filtering available through the system power supply by being tested in a representative system. The use of “test beds” are suspect. The standards and directives state that representative systems are to be used. “Test beds”, because of their nature, may not be representative.

GUIDELINE:

1.   The EMC Directive covers any and all electronic apparatus. In the case of an internal device there are two factors to consider. (A) Is the device sold as is to an end user. (B) Does the device perform a direct function. Since connection to an AC mains supply is not a governing criterion, and since the internal disk drive mentioned has a direct function and can be sold to the end user, it meets the guideline of an apparatus as defined by the EMC directive. It is therefore subject to the EFT testing.

2.   Since all electronic apparatus is subject to the EMC directive, each apparatus must show compliance to the directive. Testing one device in a representative system testing all functions of the apparatus shows compliance of the system.

3.   For different “versions” of the EUT, see TGN 006.

REFERENCE DOCUMENT(S):

The following answer is based on the 1996 draft version of the “Guidelines on the Application of Council Directive 89/336/EEC of 3 May 1989 on the Approximation of the Laws of the Member States relating to Electromagnetic Compatibility amended by Directives 92/31/EEC and 93/68/EEC.”

Note: All members are free to deviate from the above guidelines where they think them inappropriate, unworkable, or not commercially viable. Under these circumstances the Executive Committee should be informed of the decision to deviate from their guidelines, so that the matter can be reviewed. This document is copyrighted by the United States Council of EMC Laboratories (USCEL). This document is for the use of USCEL members. Members may use it as they see fit, but are not permitted to sell it.