Establishing an Isolated Ground

[sola7114]

We're on a job where the drawings call for an isolated ground t certain circuits. The system is a 3 phase 120/208 4 w ..what is the best way to establish an isolated ground for the cash register circuits?

 

[iwire]

The IG is never really allowed to be isolated.

The most you can do is run it back to the main service panel bonding point or if it is supplied by a transformer in the building back to the bonding point for that.

The drawings ask for IG but don't show how they want it done?

That is odd.

 

[iwire]

http://ecmweb.com/mag/electric_basics_isolated_grounding/

 

[kwired]

To expand a little on what Iwire said, isolated ground is not isolated from the building grounding system, where it must terminate typically at the service equipment.

It is isolated from other equipment grounding conductors all the way from service to the outlet. The isolated grounding conductor passes through all raceways, junction boxes panelboards, etc. with no connection to these enclosures and is in addition to the required equipment grounding conductor required to bond these enclosures or other non isolated grounded items.

Do not confuse isolated ground terminology to running a wire from the IG receptacle to a ground rod (and nothing else) like many seem to do.

 

[sola7114]

Thanks

Thanks

Thanks everyone...Very Helpful...Happy Memorial Day weekend