Disconnecting means for power filter feeding a SCIF

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brianthejabroni2

Member
Is a disconnecting means required for a power filter located in a SCIF ? I currently have no room to mount a 400a disconnect inside SCIF near power filter: I thought there was an exception somewhere that says I can put a plaque showing where disconnecting means is ?
 
it’s pretty much a room inside of a room that’s shielded with foil so no signals can go in or out. But yes it’s a sensitive compartment information facility.
 
Dont think we ever put them on ours. It just a filter in a feeder. Would think tutrning off the source feeder would be sufficient. You rarely mess with these unless they fail a test and show RF leaking out.
 
brianthejabroni2 said:
I thought there was an exception somewhere that says I can put a plaque showing where disconnecting means is ?
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I think the wording on LO/TO being in another room is something to the effect of “in an industrial facility with established safety procedures and under engineering supervision”…

But don’t just take my word for it, this is very conditional IIRC.

Alternative might be to make it plug-in, ie using a big 400A pin and sleeve connector.
 
I would ignore the SCIF aspect, as they don't have anything special as far as NEC goes, but if you had a room fed with a branch circuit or feeder that had a filter box in that feeder or branch circuit, would that filter box need a disconnect? I don't see anything in a code that specifically applies to this except perhaps NEC 460 Capacitors and 470 Resistors and Reactors, as a filter box has capacitors , discharge resistors, and possibly inductors installed in a box. I don't see a requirement for a disconnect for capacitor banks, but it doesn't have any restrictions like it must be in sight of it. I always assumed the feeder or circuit circuit breaker could be the disconnect, as the architects never drew local disconnects for them on plans. For all I know, the NE 460 requirements could all be inside the filter box (e.g. overcurrent device, disconnect, discharge, etc) but since they tend to state an amp limit I figured they relied on the source circuit overcurrent device for disconnect and overcurrent requirements.

Here is one source for those filters: https://www.totalemc.com/4-Line-TE--TEMPEST--Shielded-Room-Filters--ct1752.aspx
 
The definition of SCIF is correct, but they are not by definition shielded. It depends on whether there is electronic processing in the SCIF. The word you are looking for is TEMPEST. Searching that will provide the related documentation.

Mark
 
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