Ground Situations

[bure961]

I came by a 480volt service with the only ground connection was to a water line 15-20 feet after entering the building in basement and water meter was on first floor. There also looks like there was at onetime a bare ground connected to the waterline in basement to outside to maybe a ground rod that is now disconnected, not sure , cable is coming into building from outside below ground.
The poco replaced their transformer they labeled 3 phase delta, one phase is grounded [ 0 volts to ground ] and I believe it is a corner ground same as old trans connection. If this is a corner ground 480v connection should the one phase be non protected , and should there be 2 pole breakers instead ? Should the ground system be brought up to date ? Thank you to all help.

 

[GoldDigger]

I came by a 480volt service with the only ground connection was to a water line 15-20 feet after entering the building in basement and water meter was on first floor. There also looks like there was at onetime a bare ground connected to the waterline in basement to outside to maybe a ground rod that is now disconnected, not sure , cable is coming into building from outside below ground.
The poco replaced their transformer they labeled 3 phase delta, one phase is grounded [ 0 volts to ground ] and I believe it is a corner ground same as old trans connection. If this is a corner ground 480v connection should the one phase be non protected [1], and should there be 2 pole breakers instead[2] ? Should the ground system be brought up to date[3] ? Thank you to all help.

1: Yes
2: Yes, if you are referring to the main (service disconnect) breakers, breakers feeding three phase loads, breakers feeding MWBCs or single phase ungrounded-to-ungrounded loads.
3: At a minimum it needs to be restored to what was approved when it was first installed. Deliberate or accidental changes to the original installation that were not allowed when they happened are not grandfathered in. In addition, you should probably bring the ground system up to current code requirements if possible, regardless of whether it is required or not. Is somebody willing to pay for that?

 

[kwired]

Three pole breakers are allowed on a corner grounded system, the rule here is interruption of the grounded phase must be simultaneous with the ungrounded conductors - which can be done with a breaker, but fuses would not be allowed in the grounded conductor because it is possible for the fuse to open without opening the ungrounded conductors.

Add: you need to pay attention to the rating of the breakers you use, as not all breakers may be rated for use in this application.

 

[iwire]

Three pole breakers are allowed on a corner grounded system, the rule here is interruption of the grounded phase must be simultaneous with the ungrounded conductors - which can be done with a breaker, but fuses would not be allowed in the grounded conductor because it is possible for the fuse to open without opening the ungrounded conductors.

Add: you need to pay attention to the rating of the breakers you use, as not all breakers may be rated for use in this application.

I agree.

 

[iwire]

3: At a minimum it needs to be restored to what was approved when it was first installed. Deliberate or accidental changes to the original installation that were not allowed when they happened are not grandfathered in. In addition, you should probably bring the ground system up to current code requirements if possible, regardless of whether it is required or not. Is somebody willing to pay for that?

He is in MA, pretty much everything is 'grandfathered in' for the electrician.

If an actual hazard exists that is between the inspector of wires and the property owner.

Check out rules 3 & 4 in this PDF http://www.lawlib.state.ma.us/source/mass/cmr/cmrtext/527cmr12.pdf