ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (Scott35), 255 guests, and 17 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#84399 03/26/03 01:05 AM
Joined: Mar 2003
Posts: 5
C
Carnak Offline OP
Junior Member
Consider a commercial building with a three phase service and 100% generator back up.

If you use a 3 pole transfer switch, you don't break the neutral.

If you use a 4 pole switch, you break the neutral, add some extra grounding, and the system is now "Separately Derived".

When do you have to have the 4 pole transfer switch and the separately derived system?


Go Big or Stay Home
Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

Joined: Feb 2003
Posts: 169
R
Member
This same question is asked in the General Discussion Area.
Look for a post by wolfdog (backup generators)

Russ
I added this link to it. Just click it
https://www.electrical-contractor.net/ubb/Forum1/HTML/002728.html

[This message has been edited by russ m (edited 03-26-2003).]

Joined: Feb 2003
Posts: 169
R
Member
I just went into the search section of this forum (ECN) and typed in transfer switch. There are alot of threads on this subject.

Russ

[This message has been edited by russ m (edited 03-26-2003).]


Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5