Another Ground Rod Question

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dropframe

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Costa Rica
I am adding a workshop separate from the residence. This is in Costa Rica, so some things are a little different, but not much. I will be tying into the existing wiring just past the meter. Currently, at the meter, the ground from the residence main panel, the neutral from the residence main panel, the ground from the grounding rod and the neutral from the utility are all bonded. There is a 100 amp breaker between the meter and the main panel (It is physically right at the meter).

My plan is to add the workshop ground and neutral to the other four that are bonded together. I will add a second 100 amp breaker for the hot legs to the workshop.

My question is:
Do I need to put a grounding rod at the workshop and connect it to the workshop ground bar?

I will not bond the neutral and ground at the workshop, correct?
 
cuba_pete

cuba_pete

Senior Member
Location
Washington State
NEC 250.32

NEC 250.32

Of course, refer to your AHJ, but in the US:

250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.

Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non–current-carrying metal parts of equipment.

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Using the exception, (which appears to be the direction you are going) you will not bond the ground and neutral in the workshop.

Install a main in the workshop (not an MLO panel), as you will likely not be able to see or access easily the breaker for the workshop at the main panel.
 
ActionDave

ActionDave

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Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
cuba_pete said:
Of course, refer to your AHJ, but in the US:

250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
(A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.

Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non–current-carrying metal parts of equipment.

---------------------------------
Using the exception, (which appears to be the direction you are going) you will not bond the ground and neutral in the workshop.

Install a main in the workshop (not an MLO panel), as you will likely not be able to see or access easily the breaker for the workshop at the main panel.
Click to expand...
The exception you cited does not apply for feeders. It would be required to have a separate equipment ground and a grounding electrode tied to it at the out building.
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
cuba_pete said:
Install a main in the workshop (not an MLO panel), as you will likely not be able to see or access easily the breaker for the workshop at the main panel.
Click to expand...

Not so fast.

A main breaker is only required if the breaker is going to be the disconnecting means for the structure. Of course the location of the panel in Regards to where the feeder enters the structure will need to be aaddressed if OP wants wants to do this.

A disco and Milo panel is a legal option also.
 
cuba_pete

cuba_pete

Senior Member
Location
Washington State
ActionDave said:
The exception you cited does not apply for feeders. It would be required to have a separate equipment ground and a grounding electrode tied to it at the out building.
Click to expand...

Yeah, well...the exception says what it says...it doesn't say feeder...it's kind of like English.

Since the DIY OP was describing a MWBC ("workshop ground bar"), I BI'd that.
 
cuba_pete

cuba_pete

Senior Member
Location
Washington State
jumper said:
Not so fast.

A main breaker is only required if the breaker is going to be the disconnecting means for the structure. Of course the location of the panel in Regards to where the feeder enters the structure will need to be aaddressed if OP wants wants to do this.

A disco and Milo panel is a legal option also.
Click to expand...

His DIY description is likely a MWBC ("workshop ground bar" likely in a sub panel), not a feeder. It's not seen clearly from here.
 
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GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
cuba_pete said:
I agree, but that is what my shop has too, so I can see it.
Click to expand...

Just because it is branching off to the garage does not make it a branch circuit.
It is possible to have a single branch circuit going to the garage (no OCPD for it in the garage) as well as a feeder going to subpanel (OCPD inside the garage and so branches originating there). But that violates the spirit if not the letter of the one branch / one feeder rule for the separate building.

If you have nothing but a 100A branch circuit going to the garage, how are you feeding the lighting, for example.
 
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