250.50 / 250.52(A)(3) for second structure

[Steve AR]

I have questions regarding adding a small building near the main existing old building, the new small addition is for a chillier on a concrete slab.
1) Do we have to bond the rebar's of this new slab to be, to the existing grounding grid of the main building located few feet away?
There will be no service in the new chiller building.The chiller will be grounded to the old existing building system.
2) If we do not bond the rebar's to the existing grounding grid in the premises is this a violation?
3) Do we have to do a concrete -encased electrode to every concrete slab placed per 250.52(A)(3), or only to the one that will get a service?

The NEC 250.50 Grounding electrode system:
All grounding electrodes as described in 250.52 (A)(1) through (A)(6)that are present at each building or structure served shall be bonded together to form the grounding electrode system.
250.52(A)(3) concrete -encased electrode what I am referring to.
thank you
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[RUWired]

1) Do we have to bond the rebar's of this new slab to be, to the existing grounding grid of the main building located few feet away?
There will be no service in the new chiller building.The chiller will be grounded to the old existing building system.
2) If we do not bond the rebar's to the existing grounding grid in the premises is this a violation?
3) Do we have to do a concrete -encased electrode to every concrete slab placed per 250.52(A)(3), or only to the one that will get a service?

(1) No, not to the existing building, but if the new building has a feeder to it, and it meets the requirements, you'll have to use it for the new building.
(2) there is not a requirement to bond two different structures together, although to keep the same potential if that close it wouldn't hurt.
(3)If all the different slabs have service or feeders to them, it is required to have a GES installed, whether its a CCE or any other electrode.

 

[augie47]

I have questions regarding adding a small building near the main existing old building, the new small addition is for a chillier on a concrete slab.
1) Do we have to bond the rebar's of this new slab to be, to the existing grounding grid of the main building located few feet away?

as RUWired noted, not required

There will be no service in the new chiller building.The chiller will be grounded to the old existing building system.
2) If we do not bond the rebar's to the existing grounding grid in the premises is this a violation?
3) Do we have to do a concrete -encased electrode to every concrete slab placed per 250.52(A)(3), or only to the one that will get a service?

The way I read it, 250.32 requires you to use all the electrodes described in Part III if they are avaialble. If the new building has a CEE, you must use it

The NEC 250.50 Grounding electrode system:
All grounding electrodes as described in 250.52 (A)(1) through (A)(6)that are present at each building or structure served shall be bonded together to form the grounding electrode system.
250.52(A)(3) concrete -encased electrode what I am referring to.
thank you
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