I'm trying to improve my understanding of the CISPR 14.1 EMC test procedures and requirements, with a view to performing precompliance testing. In particular, I'm looking at conducted emissions measurements.
My understanding is that conducted emissions measurements are applied only to mains cables, but reading CISPR 14.1 I'm unable to confirm that this is the case.
Measurements in the 150 kHz to 30 MHz range are made on terminals:
Terminals are defined as conductive parts, suitable for re-usable electrical connection to external circuits
which I understand to also refer to connectors, not just terminal blocks.
There are additional stipulations as to which terminals the limits apply to, which in addition to the obvious mains supply terminals are:
On additional terminals of appliances as well as on load and additional terminals of regulating controls incorporating semiconductor devices the relaxed limits given for "additional terminals" in columns 4 and 5 apply.
No terminal voltage limits apply for leads, which are not easily extensible by the user (permanently connected, or provided with a specific connector), which are shorter than 2 m, and which connect the equipment with an auxiliary apparatus or device, (e.g. semiconductor speed controls, power plugs with AC-DC converters).
Our device has a 12 VDC solenoid mounted externally, connected by a specific connector and 1.5 m length of cable, but I don't think that the solenoid would be classified as an "auxiliary apparatus", which would indicate that it would require testing.
Here's a block diagram/simplified schematic. There are some electronics running off the 12 VDC too which control the relays.
I've searched for other CISPR 14.1 test reports to compare to, but none that I can find have any more terminals than just the power supply.
So what terminals/connections/cables does one actually apply conducted emissions testing to?