Service/Feeder tap?

[yatishsharma]

Hi,

My question is regarding 240.21 b application to tap in following scenario:

I have a 2000Amp service switch fused at 2000amps. The service switch feeds a switchboard rated for 2000amps.

1. If tap after the service switch ( on buss of the switchboard or on the load side of switch), the feeder shall be follow the tap rules. 1/10 of the ampacity of switchboard and the length restriction of 10'.
2. If tap is before the service switch ( on load side of the service switch or inside the C/T), what rule shall the feeder sizing follow? the service feeder (based on OCP) or tap feeder as i am tapping the service switch?

Thanks

 

[augie47]

I believe in scenario #2 you meant to say "line side of the service switch".
The tap rules of 240.21 do not apply to service "taps" possibly because 230.70 keeps their interior length to a minimum.

 

[infinity]

As Augie stated 240.21 is for feeder taps not taps on service entrance conductors.

 

[Smart $]

...The tap rules of 240.21 do not apply to service "taps" possibly because 230.70 keeps their interior length to a minimum.

...and taps of service conductors are still service conductors. Article 230 requirements serve to determine the service tap conductor size and equipment ratings at the load end.