Ct cabinets

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achasing

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Hello all, new here. Never really paid attention, but could someone explain to me when a CT cabinet needs to have a disconnect and fuses. I've done many commercial services 800/1200amp and some have had disconnects and fuses, and others have not. I thought it was based on distance from the gear, but I just did one that went through the wall directly to the gear and it had a disco. Is it a village requirement? Thanks for any answers, couldn't find anything in the code book.
 
Are these CT cabinets, current transformer cabinets? If so, there should never be a fuse in a ct circuit. If equipped with disconnects for the cts, they should be make-before-break shorting type disconnects. If CT has another meaning please explain.
 
Around the Chicago land area when I come off a ground mounted ComEd transformer I run the feeds, say 2-3 1/2" with 500's to a CT cabinet which is mounted on the outside of the building. On this cabinet door the meter is mounted. ComEd will come and mount doughnut CT and trim in the meter. The CT has line and load lugs, from the load side of the CT cabinet, you go to the gear. I was just curious why some CT cabinets have a main disconnect on it to kill power to the whole building and others do not. I have mounted CT cabinets with disconnecting for the whole building and ones that don't. Just curious. I always figured if the gear or MDP wasn't within 5' of the ct, this would be the reason for the outside disconnecting.
 
Just curious, what type of donut ct has line and load lugs. The only type of donut ct that I have seen has only secondary output lugs, the input is the cable around which it is wrapped. If it is an auxiliary ct, then it can have both input (primary) and output (secondary) terminals.
 
I'm confused as well since I've never seen a CT with line and load lugs. Are we possibly talking about CPTs for providing power to the trip devices or PTs for voltage metering?
 
When there is no disconnect on the CT cabinet, the CT's are bolted on between the line and load lugs, They are what ties the 2 together. When there is a disconnect, I believe the put the CT around the line cables. Sorry for the confusion.
 
Thanks for the clarification. Just to make sure I understood you....

The CTs are on the feeder cables. The feeder cables either have a disconnect and fuses or no disconnect. Your question is when does Code or good design practice call out for disconnects or not and is it based on the distance of the cable from the source (transformer?) to the switchgear. Is this correct?
 
In North East Ohio we have to have a disconnect before the cts on a 480 v or higher service, but that is the utility company that specs that
 
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