If you’re reading this, you may be seeking how to avoid EMC testing by possibly using some EMC testing exemptions. Although this brief article will highlight some possible exemptions for testing. You are still responsible for your product. The majority of EMC testing performed at EMC Bayswater for the North American market i.e. the United States. Falls under the requirements of FCC Part 15 (CFR 47) Subpart B. FCC Part 15, Subpart B is for the testing of products that are not transmitters, receivers or transceivers.
These types of products are known as unintentional radiators. There are various types of products that fall under the testing exemptions list as per FCC Part 15, Subpart B, Section 15.103. Before going through some of these exemptions please note that the FCC do still recommend testing even if the product is exempt. If a product that falls under any exemption causes interference then;
“The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected. Although not mandatory, it is strongly recommended that the manufacturer of an exempted device endeavor to have the device meet the specific technical standards in this part”
FCC Part 15, Subpart B, Section 15.103, FCC Testing Exemptions
(1) A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.
(2) A digital device used exclusively as an electronic control or power system utilized by a public utility or in an industrial plant. The term public utility includes equipment only to the extent that it is in a dedicated building or large room owned or leased by the utility and does not extend to equipment installed in a subscriber’s facility.
(3) A digital device used exclusively as industrial, commercial, or medical test equipment.
(4) A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.
(5) Specialized medical digital devices (generally used at the direction of or under the supervision of a licensed health care practitioner) whether used in a patient’s home or a health care facility. Non-specialized medical devices, i.e., devices marketed through retail channels for use by the general public, are not exempted. This exemption also does not apply to digital devices used for record keeping or any purpose not directly connected with medical treatment.
(6) Digital devices that have a power consumption not exceeding 6 nW.
(7) Joystick controllers or similar devices, such as a mouse, used with digital devices but which contain only non-digital circuitry or a simple circuit to convert the signal to the format required (e.g., an integrated circuit for analog to digital conversion) are viewed as passive add-on devices, not themselves directly subject to the technical standards or the equipment authorization requirements.
(8) Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Digital devices that include, or make provision for the use of, battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, do not fall under this exemption.
Additional FCC EMC Testing Exemptions
In addition to the FCC exemptions listed in FCC Part 15, Subpart B, Section 15.103 there are a few other interesting useful exemptions.
(9) Home-built devices. -As per FCC Part 15, Subpart A, Section 15.23 (a) specifies:
Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use.
(10) The definition of a Digital Device as per FCC Part 15, Subpart A, Section 15.3 (k) specifies:
Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; inclusive of telephone equipment that uses digital techniques or any device or system that generates and uses radio frequency energy for the purpose of performing data processing functions, such as electronic computations, operations, transformations, recording, filing, sorting, storage, retrieval, or transfer. A radio frequency device that is specifically subject to an emanation requirement in any other FCC Rule part or an intentional radiator subject to subpart C of this part that contains a digital device is not subject to the standards for digital devices, provided the digital device is used only to enable operation of the radio frequency device and the digital device does not control additional functions or capabilities.
Note: Computer terminals and peripherals that are intended to be connected to a computer are digital devices.
Thus this means that a low-frequency device that doesn’t generate timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second i.e. less than 9 kHz could be exempt from testing.
CE EMC Testing Exemptions
CE testing is not always required, yet, you do need to prove compliance. This may be achieved by other means such as technical assessment. In many instances such as Harmonic current emissions, there may be a simple exemption depending upon the product. For immunity, the applicability of much of the testing is based upon the construction of the product. And it’s associated cable functional lengths.
RCM EMC Testing Exemptions
Cautionary note (as per FCC rules):
Responsible parties should note that equipment containing more than one device is not exempt from the technical standards in this part unless all of the devices in the equipment meet the criteria for exemption. If only one of the included devices qualifies for exemption, the remainder of the equipment must comply with any applicable regulations. If a device performs more than one function and all of those functions do not meet the criteria for exemption, the device does not qualify for inclusion under the exemptions.