ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Where is Everyone?
by gfretwell - 04/09/21 01:08 AM
HI gang, long time since I was here...
by gfretwell - 04/09/21 01:02 AM
Lock-down Thread
by gfretwell - 04/06/21 09:30 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 7 guests, and 17 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Classroom confusion #99636 08/22/06 11:47 AM
Joined: Mar 2005
Posts: 399
A
Alan Nadon Offline OP
Member
This is the situation.
Portable classroom composed of two halves, (think of a double wide mobile home) each with a 100 amp main breaker panel that controls the circuits in that half of the building.
The electrician brings TWO 100 amp feeders out to the panels. Each originates in the same service panel with a 2pole 100 breaker.
Based on 225.30 (formerly 225.8 & 9[1996] and 230.84[1990]) only ONE feeder or branch circuit, with exceptions for firepumps etc.
To comply with the Code should the electrician (1) use a 200 amp breaker listed for two conductors per pole (2) handle tie the two 100 amp breakers, (3) either or (4)something else ?
Note the panels inside are ten feet apart.
We build them around here and use them but, I'm just not sure. [Linked Image]
Alan--


Alan--
If it was easy, anyone could do it.
2017 / 2014 NEC & Related Books and Study Guides
Re: Classroom confusion #99637 08/22/06 12:56 PM
Joined: Dec 2003
Posts: 751
E
earlydean Offline
Member
I would supply a small 150-200 amp main breaker panel mounted on the outside of the classroom, then feed each panel with a 100 amp feeder. Maybe even supply a branch circuit for outside lighting.

It may be, that when the calculations are done for the combined load of both halves, that a 100 amp feeder would suffice. If so, then you could feed the closer panel, and subfeed the other from the first.


Earl
Re: Classroom confusion #99638 08/22/06 03:44 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
I'm thinking a single 200 amp feeder run to a 200 amp disconnect mounted inside or outside the structure. If you feel that the two inside panels are "grouped" as required by 225.34(A), then the feeder can be run to the structure and then tapped at that point.


Few things are harder to put up with than the annoyance of a good example.
Re: Classroom confusion #99639 08/24/06 02:09 PM
Joined: Mar 2005
Posts: 399
A
Alan Nadon Offline OP
Member
Problem solved [Linked Image]
One disconnect, (service or not) rated 200 amps (225.30 & 34) with one feeder to each double classroom.
At the classrooms a W.P. junction box with two 100 amp taps (per 240.21 tap rule) to the panels.
Done & Done.
Alan--


Alan--
If it was easy, anyone could do it.
Re: Classroom confusion #99640 08/24/06 03:13 PM
Joined: Dec 2003
Posts: 751
E
earlydean Offline
Member
And don't forget to install a couple of ground rods.


Earl

Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Vlado
Vlado
Croatia
Posts: 28
Joined: February 2011
Show All Member Profiles 
Top Posters(30 Days)
BigB 1
Popular Topics(Views)
277,658 Are you busy
211,275 Re: Forum
198,311 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3