2 Services - 1 Ground?

[sevlander]

we have a situation where an existing overhead service is getting an upgrade. No increase in size, just modernization. In the process a tenant will be separated from the original 120/240 volt 3 phase service and receive their own 120/208 volt 3 phase service drop. The utility has both available at site.the services will be mounted in the same room. Can the smaller be ground to the larger service ground via an irreversable splice or do they have to be 2 separate grounds to the water pipe and electrode system? We have differences of opinion here and can use some clarifcation.

 

[barbeer]

I don't see a problem with sharing the system as long as the GEC is sized accordingly.

 

[sevlander]

but does any code article # specifically allow or reject it?

 

[lowryder88h]

One Grd

One Grd

Are you thinking of art. 250.64 (D) grounding electrode conductor taps??

 

[barbeer]

250.58 should also apply here.

 

[e2me]

maybe

maybe

we have a situation where an existing overhead service is getting an upgrade. No increase in size, just modernization. In the process a tenant will be separated from the original 120/240 volt 3 phase service and receive their own 120/208 volt 3 phase service drop. The utility has both available at site.the services will be mounted in the same room. Can the smaller be ground to the larger service ground via an irreversable splice or do they have to be 2 separate grounds to the water pipe and electrode system? We have differences of opinion here and can use some clarifcation.

The answer is yes and no if the original is sized to meet the combined load of both services then yes you may but if not then no remember these are sized by 250.66