CT - Marshallinb Box and Test Terminals
CT - Marshallinb Box and Test Terminals
(OP)
Hello every one,
I've a CT marshalling box that getter 3 CT's (one for each phase).
These box received the wiring cables from each CT secondary terminal box and from that marshalling box it'll be connected the cables that goes to the meters and relays installed in a control house.
To connect the wiring from the outside, the terminals in the marshalling box are located horizontally in a support rail. The terminals are screw clamp and with some kind of slinding bar, PHONEXI CONTACT URTK/S BEN. These sliding bar open from bottom to top. The terminals that received the cables form the CT secondary box have a slinding bar type PHOENIX SB2-RTK/S and the cables that ar going tho the control roomm have a slinding bar type PHOENIX SB4-RTK/S.
From waht I undersatnd this sliding bars installed in the URTK/S terminals have the propose to short-circuit the secondarys of the CT's when they aren't use by a realy or meter, so they avoid that a secondary is opened. And also to test the circuits.
After the CT tests are donne, and if all the secondaries of the CT are used, these sliding bars (SB4) should remain in the open position. Am I right?
Thank you in advanced.
I've a CT marshalling box that getter 3 CT's (one for each phase).
These box received the wiring cables from each CT secondary terminal box and from that marshalling box it'll be connected the cables that goes to the meters and relays installed in a control house.
To connect the wiring from the outside, the terminals in the marshalling box are located horizontally in a support rail. The terminals are screw clamp and with some kind of slinding bar, PHONEXI CONTACT URTK/S BEN. These sliding bar open from bottom to top. The terminals that received the cables form the CT secondary box have a slinding bar type PHOENIX SB2-RTK/S and the cables that ar going tho the control roomm have a slinding bar type PHOENIX SB4-RTK/S.
From waht I undersatnd this sliding bars installed in the URTK/S terminals have the propose to short-circuit the secondarys of the CT's when they aren't use by a realy or meter, so they avoid that a secondary is opened. And also to test the circuits.
After the CT tests are donne, and if all the secondaries of the CT are used, these sliding bars (SB4) should remain in the open position. Am I right?
Thank you in advanced.






RE: CT - Marshallinb Box and Test Terminals
If the disconnect terminals should be open or closed depends on where in the circuit they are located.
RE: CT - Marshallinb Box and Test Terminals
But the PHONEXI CONTACT URTK/S BEN with PHOENIX SB2 or SB4-RTK/S were use only for testing proposes, right?
Thank you in advanced.
RE: CT - Marshallinb Box and Test Terminals
You should be able to tell how it works by putting it in both positions while injecting current. Visually it should be clear what it does. I can't tell by the cut sheet how it works, it looks like it shorts the CT's at the terminal block.
RE: CT - Marshallinb Box and Test Terminals
Please find attached the diagram were you could see the marshalling box connections.
Could you please help understand the function of the PHOENIX SB2-RTK/S and SB4-RTK/S slide bars?
After the CT tests are donne, and if all the secondaries of the CT are used, these sliding bars should remain in the open position. Am I right?
Thank you
RE: CT - Marshallinb Box and Test Terminals
RE: CT - Marshallinb Box and Test Terminals
RE: CT - Marshallinb Box and Test Terminals
RE: CT - Marshallinb Box and Test Terminals
RE: CT - Marshallinb Box and Test Terminals
1) If changes to the protection scheme are made, it's much easier if all of the CT secondary leads/terminals are available.
2) When shorting a CT it is ideal to short across the full ratio. As a matter of practice, 50% of the secondary winding, at a minimum, should be shorted. In this case it appears that the 50% rule is being met, but only barely.