[RFI] Computer cases and RFI

[Tim Groat]

The requirements for PC's custom assembled from tested component under a 
"Declaration of Conformity" are in sections 15.32 and 15.102 of the FCC 
rules <http://www.fcc.gov/oet/info/rules/part15/part15-91905.pdf>. They 
don't mention approvals for cases per se, but the approval rules for CPU 
boards implies the case is expected provide at least 6dB shielding 
effectiveness. But there's nothing I see in the regulations that requires 
the cases to meet any performance test of their own. With only 6dB being 
expected of them anyway, the cases really aren't that big an issue for 
rules enforcement. The shop is probably in the clear as long as they use 
tested CPU boards, power supplies, and peripherals, and apply the correct 
markings to the unit ("Assembled from tested components..."). The idea is 
that machines built from tested parts will pass the FCC emissions test as a 
whole--but reality is another matter, with clock and bus speeds higher for 
each new processor generation.

73,
--Tim (KR0U)

>Alan NV8A <nv8a at att.net>:
>
>So here is the question: computers are supposed to comply with FCC 
>emission regulations, but how can a computer built into such a case pass? 
>Granted that home-brew computers don't get tested, but can a store legally 
>sell someone a custom-built computer (this store does: you choose your 
>case and what components you want in it) that could never in a million 
>years pass the FCC tests?