Does 430.28 Apply?
Does 430.28 Apply?
(OP)
I want to install a subpanel off of an existing panel. The subpanel will feed three combination loads.
The existing panel is fed by 3-350mcm feeders per phase. The tap conductors will be 2-250mcm cables per phase, and will be bolted to the existing panel bus bars. The subpanel will be located within 10ft of the existing panel. The subpanel will have a 400A fused disconnect switch and feed three branch circuits that are fused. The fused disconnect and three branch circuit fuse sets are within the subpanel. The three branch circuits vary in length from 50ft to 275ft to each branch combination load. Each combination load is a panel that includes motors and other electrical loads. The panels are adequatly fused and protected with overloads, disconnects, etc.
Assuming that the feeder, tap, and branch conductors are adequate for the connected loads and OCPD's, does 4.28 apply in this situation? Specifically, may I have tap conductors that are atleast 1/3 the ampacity of the feeders without any OCPD between the existing panel and the subpanel (containing the 400A fused disconnect and branch circuit fuses)? For the comination loads, the individual motor fuses, overloads, etc., are actually more than 25ft away from the tap. Only the branch conductor fuses are contained in the subpanel.
The existing panel is fed by 3-350mcm feeders per phase. The tap conductors will be 2-250mcm cables per phase, and will be bolted to the existing panel bus bars. The subpanel will be located within 10ft of the existing panel. The subpanel will have a 400A fused disconnect switch and feed three branch circuits that are fused. The fused disconnect and three branch circuit fuse sets are within the subpanel. The three branch circuits vary in length from 50ft to 275ft to each branch combination load. Each combination load is a panel that includes motors and other electrical loads. The panels are adequatly fused and protected with overloads, disconnects, etc.
Assuming that the feeder, tap, and branch conductors are adequate for the connected loads and OCPD's, does 4.28 apply in this situation? Specifically, may I have tap conductors that are atleast 1/3 the ampacity of the feeders without any OCPD between the existing panel and the subpanel (containing the 400A fused disconnect and branch circuit fuses)? For the comination loads, the individual motor fuses, overloads, etc., are actually more than 25ft away from the tap. Only the branch conductor fuses are contained in the subpanel.






RE: Does 430.28 Apply?
RE: Does 430.28 Apply?
RE: Does 430.28 Apply?
Why are you asking about motor feeder taps? Shouldn't you be considering 240.21(B)(1) or (2)?
RE: Does 430.28 Apply?
240.21(B)(1) leads me to think that branch circuits leaving the subpanel are okay on the load side of the tap conductor.
But, 240.21(B)(2) leads me to think that the tap as well as the branch circuits must terminate inside the "switchboard, panelboard, disconnecting means, or control devices they supply".
What's your take on this?
RE: Does 430.28 Apply?
RE: Does 430.28 Apply?
RE: Does 430.28 Apply?
I believe 430.28(F) might apply if there was one overcurrent device being fed by the motor feeders and feeding a single motor branch circuit.
240.21(B)(1) requires that "the tap conductors do not extend beyond the switchboard, panelboard, disconnecting means, or control devices they supply", not 240.21(B)(2). Some of the differences are the length of the tap and the necessity in 240.21(B)(2) that the tap conductors "terminate in a single C/B or single set of fuses", etc.
Sounds like 240.21(B)(2) should apply to your situation.
RE: Does 430.28 Apply?
o Gutter Tap.
o Sub-feed lugs.
o Through-feed lugs.
Check if this could be helpfull for your application.
http://www.cutler-hammer.eaton.com/unsecure/html/catalogs/CAT71.htm