Ct switch install

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bpk

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Northern Minnesota
We are installing some small Ct's to monitor the status of equipment in a building, like roof fans and makeup air units. My question is that it would be nice to install a j-box nippled to the panel to put our ct's in and run 1 phase conductor from each branch circuit that we will be monitoring through the nipple, loop through the ct, and back thru the nipple into the panel. Is that a violation to have only 1 phase conductor per piece of equipment run thru the nipple? Should we be concerned with any possible induction? FWIW there are 3 roof fans and 1 Make up air unit all 480v 3 phase and pretty low FLA.
 
Not an issue.
If the conductor goes 'in' through the nipple, makes a 180? turn and then goes back 'out' through the nipple, it is behaving no different than a normal switch leg.
 
jim dungar said:
Not an issue.
If the conductor goes 'in' through the nipple, makes a 180? turn and then goes back 'out' through the nipple, it is behaving no different than a normal switch leg.
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Maybe ... but we have four CCC here.


bpk said:
We are installing some small Ct's to monitor the status of equipment in a building, like roof fans and makeup air units. My question is that it would be nice to install a j-box nippled to the panel to put our ct's in and run 1 phase conductor from each branch circuit that we will be monitoring through the nipple, loop through the ct, and back thru the nipple into the panel. Is that a violation to have only 1 phase conductor per piece of equipment run thru the nipple? Should we be concerned with any possible induction? FWIW there are 3 roof fans and 1 Make up air unit all 480v 3 phase and pretty low FLA.
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Do some calcs and see if you don't need to derate any of the conductors. Even if you don't, I'm not sure if the derating would cause a need to lower the ampacity of the over current protective device. Someone will chime in.

What's wrong with putting the CT in the panel and bringing your CT leads through the nipple to your JB?

Jason
 
lakee911 said:
Maybe ... but we have four CCC here.
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Big assumption.

1) The OP was about a problem with inductance.
2) The OP said they were only running 1phase conductor per piece of equipment through the nipple.
3) No mention was made that all of the circuits would be run through a single nipple.
 
I was thinking of running 1 phase from each piece of equipment thru the same nipple. They could be A,B,or C phase or alternate between. What would be the problem with 4 conductors, derating? I would rather put them in a box off to the side rather than clutter up the panel. Thanks guys for all your knowledge
 
bpk said:
I was thinking of running 1 phase from each piece of equipment thru the same nipple. They could be A,B,or C phase or alternate between. What would be the problem with 4 conductors, derating? I would rather put them in a box off to the side rather than clutter up the panel. Thanks guys for all your knowledge
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There would be no issue, if it is a nipple, it is less then 24 inches and would not require derating.
 
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