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Joined: Jul 2004
Posts: 49
G
Member
In terms of overcurrent/shortcircuit protection, are the conductors feeding off a panelboard's feed-thru lugs considered to be tap conductors and subject to Article 240.21? In particular, I have a 30hp 3ph, 208v, elevator application where I would like to utilize 240.21(F) and use the feed-thru lugs of a 400A main panel to feed the elevator controller breaker. Any and all guidance will be appreciated.

Joined: Feb 2004
Posts: 494
M
Member
Hi,
look at 240.21(b),430.28

the answer is NO you can not.

the feeder/tap MUST terminate at an OCPD...the feed throught lugs of a panelboard ARE not an OCPD.

another problem is the ocpd for the panel wont cover the protection requirements you need.


that said..if the panel will handle the additional load i would just install a disconnect/ocpd next to that panel and feed from that.

hope that helps..

-regards

greg


[This message has been edited by mustangelectric (edited 03-18-2005).]

Joined: Jul 2004
Posts: 49
G
Member
Greg,

In this case, the tap conductors off the 400A feed thru lugs will terminate in a 225A breaker that will feed the elevator controller. The tap conductors are 2/0 awg thwn, which is more than 1/3 the ampacity of the panel board and main breaker(400A) feeding the panelboard. There is also less than 25 feet in length between the origin of the tap and the elevator breaker. I'm giving you more info to pull some more teaching out of you.

Joined: Feb 2004
Posts: 494
M
Member
Hi,
I would have to say that this would be within the bounds of the articles.

the only problem i really see is that 30 horse motor cranking up..i am guessing that the 400a panel is already full and you are trying to get more mileage out of it..

what kind of elevator? material or people?

-regards

greg



[This message has been edited by mustangelectric (edited 03-18-2005).]

Joined: Jul 2004
Posts: 49
G
Member
Greg, thanks for bantering back and forth with me. In this case, this 400A panel is also serving a number of small loads. The 30HP elevator controller is of a soft start type, but this manufacturer would not recommend a size breaker to feed the unit. I sized the the breaker based on 430.52(C)(1)excpt.(1). I was trying to avoid buying a panel that would handle a 200 or 225A OCPD feeder/branch device(puts you into a higher end panel) since I had to shunt trip anyway. This elevator moves people primarily.

Joined: Jan 2003
Posts: 4,391
I
Moderator
GamecockEE

It seems like a perfectly good solution.

Either come off the panel lugs with 400 amp conductors and run as far as you want or use the tap rules as you already suggested.

You could use either the 10' or 25' tap rules.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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