The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
Trumpy 8
sparkyinak 7
Who's Online
0 registered (), 81 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#42597 - 09/23/04 02:39 PM Isolated Ground
Sparks30 Offline
Member

Registered: 03/23/02
Posts: 125
Loc: Connecticut.usa
I am doing my first I.G system. From what I have read is, you bond all of your grounding conductors together at the transformer. The system is a 480 panel feeding a 120\208 trans. So I should bond them together and seperate the ground and the neutral at the 120 panel. Any help Thanks

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#42598 - 09/23/04 04:55 PM Re: Isolated Ground
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
Sparks30;

Sounds like you have a Step-Down Transformer within the premisis, which will be driving the 208Y/120 VAC Equipment (a Separately Derived System, in other words), you will connect all the Grounding and Grounded Conductors + the Grounding Electrode Conductor and Main Bonding Jumper to the XO Terminal of the Secondary.
At the first Panelboard (actual name for "Sub Panel"), the Grounded Conductor - AKA "Neutral" will terminate on a Bus, which is Isolated / Insulated from the Panelboard's Enclosure (the "Can").

The EGC (Equipment Grounding Conductor) lands on either a Lug, or a Grounding Bus which is Electrically connected to the metallic enclosure - thereby Bonding the Enclosure.

For the IGC (Isolated Grounding Conductor), setup an additional Isolated / Insulated Bus kit - similar to the one for the System's Grounded Conductor (no Electrical connection at the Panelboard), and land the IGCs for both the Branch Circuits and the IGC "Feeder" from the Transformer, on this Bus.

Since there will be quite a few terminations to the "XO" point, get a multi Conductor lug (3 or 4 Conductor) to mount on "XO", land the Grounded Conductor(s), the Grounding Electrode Conductor and the Main Bonding Jumper to "XO".
Use an additional multi Conductor lug on the Transformer's Enclosure, then land the Main Bonding Jumper, the EGCs and the IGCs to this lug.

Below is a drawing that may help - just "convert" the system to an SDS, instead of a PoCo supplied system.
This Drawing is IG Details #1 , which is located in the Technical Reference Section .
Many more items may be found in the same area.

Scott35

_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top
#42599 - 09/23/04 06:13 PM Re: Isolated Ground
Sparks30 Offline
Member

Registered: 03/23/02
Posts: 125
Loc: Connecticut.usa
This is great info but the drawings do not match my setup. I have a utility co transformer that feeds a 277/480 switchgear. From there it goes to a 277/480 panel. The 277/40 panel feeds the 277/480 step down transformer 120/208. In this x-former should I bond all grounded and grounding conductors together. Thanks

Top
#42600 - 09/24/04 06:32 PM Re: Isolated Ground
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
Sparks30;

 Quote:

In this x-former should I bond all grounded and grounding conductors together


Yes!


Scott35
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals