code question: CT allowed inside disconnect?
code question: CT allowed inside disconnect?
(OP)
Hello,
Code question! Is a current transformer (CT) allowed inside a fused disconnect/fused safety switch? Seems like the NEC doesn't say... I've looked in article 312 and article 404.
Also, if the CT is allowed inside the FSS, would a tap for the voltage (for a power meter) also be allowed inside the FSS? My brain is telling me that a CT is a little different from a voltage tap because the CT operates by electromagnetic induction & doesn't require direct connection.
Basically it looks like someone is trying to avoid having a separate CT cabinet for the meter.
Thanks,
Brian
Code question! Is a current transformer (CT) allowed inside a fused disconnect/fused safety switch? Seems like the NEC doesn't say... I've looked in article 312 and article 404.
Also, if the CT is allowed inside the FSS, would a tap for the voltage (for a power meter) also be allowed inside the FSS? My brain is telling me that a CT is a little different from a voltage tap because the CT operates by electromagnetic induction & doesn't require direct connection.
Basically it looks like someone is trying to avoid having a separate CT cabinet for the meter.
Thanks,
Brian






RE: code question: CT allowed inside disconnect?
If the CTs/PT taps are for revenue metering, it's unlikely that the serving utility wound permit them installed in other than a separate sealed compartment.
RE: code question: CT allowed inside disconnect?
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: code question: CT allowed inside disconnect?
I know of several installations where small metering CT's were placed in fused disconnects because that was a convenient place to connect the metering for monitoring some processes. I can't say if it was according to code. I did not find a definitive answer when I investigated one of those installations.
IMHO, the installation was safe, but that opinion would never stand up in court if something happened inside the switch.
RE: code question: CT allowed inside disconnect?
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: code question: CT allowed inside disconnect?