Detached shed w/panel always require 2 rods?

[LarryFine]

Oops! Might belong in NEC forum. Can this be moved if necessary, please?



A 20a 120/240v 12/3 UF underground feeder to a detached shed. If the source breaker is a 2-pole, we have a MWBC, and we attach lights to one line and receptacles to the other, we still need a 2p disco, right?

But, if we put in a 4- or 6-space ML panel, we need an electrode system, too. We'd need 2 rods, not smaller than #8 cu GEC, and it can't be bare wire. How far can each end be bare and still be covered?

The PVC runs from 24" below grade and ends at the floor, and will not run to the panel, so the UF and GEC will be visible. I want to run the GEC through the same 1" PVC sleeve. I may just use #6 anyway.

Any reason the rods and the GEC and jumper can't be buried in the same trench as the UF? Have I missed anything?

Danke,

 

[Dennis Alwon]

But, if we put in a 4- or 6-space ML panel, we need an electrode system, too. We'd need 2 rods, not smaller than #8 cu GEC, and it can't be bare wire. How far can each end be bare and still be covered?

I don't understand why the wire can't be bare- This is not an NEC requirement as you know. I see no problem with them in the same trench.

 

[JohnJ0906]

I don't understand why the wire can't be bare- This is not an NEC requirement as you know. I see no problem with them in the same trench.

Check 250.64(B), last sentence. A #8 GEC has to be protected.

 

[Jim W in Tampa]

Check 250.64(B), last sentence. A #8 GEC has to be protected.

protection from damage ,its not saying insulated

 

[Dennis Alwon]

protection from damage ,its not saying insulated

My thoughts exactly. Thank you

 

[Jim W in Tampa]

My thoughts exactly. Thank you

most will ahj will let you run #4 bare solid without protection, but number 8 is easy damage and cut

 

[Dennis Alwon]

most will ahj will let you run #4 bare solid without protection, but number 8 is easy damage and cut

Which brings us back to the original question of why does it need to be insulated in Larry's case?

 

[billsnuff]

a failure to communicate...........

a failure to communicate...........

pehaps 'bare' in this case meant unprotected and not stripped.......what say you larry?

 

[Dennis Alwon]

A 20a 120/240v 12/3 UF underground feeder to a detached shed. If the source breaker is a 2-pole, we have a MWBC, and we attach lights to one line and receptacles to the other, we still need a 2p disco, right?

This is correct.

 

[Dennis Alwon]

pehaps 'bare' in this case meant unprotected and not stripped.......what say you larry?

If that is what he meant then I would say it needs protection only where exposed.

 

[Jim W in Tampa]

Oops! Might belong in NEC forum. Can this be moved if necessary, please?



A 20a 120/240v 12/3 UF underground feeder to a detached shed. If the source breaker is a 2-pole, we have a MWBC, and we attach lights to one line and receptacles to the other, we still need a 2p disco, right?

But, if we put in a 4- or 6-space ML panel, we need an electrode system, too. We'd need 2 rods, not smaller than #8 cu GEC, and it can't be bare wire. How far can each end be bare and still be covered?

The PVC runs from 24" below grade and ends at the floor, and will not run to the panel, so the UF and GEC will be visible. I want to run the GEC through the same 1" PVC sleeve. I may just use #6 anyway.

Any reason the rods and the GEC and jumper can't be buried in the same trench as the UF? Have I missed anything?

Danke,

Depends on if you call this 1 circuit or 2. Personally i see it as one circuit and a simple 2 pole 20 amp switch could be disconnect or a $ 10 pullout like you use for the AC
And if its 1 circuit no ground rod

 

[LarryFine]

pehaps 'bare' in this case meant unprotected and not stripped.......what say you larry?

I meant without physical protection. If I were to use the spiral-wrapped bare wire, or sleeve it, just how far away from each end's termination can that cover stop?

 

[LarryFine]

Depends on if you call this 1 circuit or 2. Personally i see it as one circuit and a simple 2 pole 20 amp switch could be disconnect or a $ 10 pullout like you use for the AC
And if its 1 circuit no ground rod

Can we call it a single circuit even if it's supplying two separate 120v loads, like lights on one line and receptacles on the other?

We may decide to use a 4- or 6-space ML panel anyway, and install a few 15a breakers, which triggers the electrode requirements.

 

[Dennis Alwon]

Depends on if you call this 1 circuit or 2. Personally i see it as one circuit and a simple 2 pole 20 amp switch could be disconnect or a $ 10 pullout like you use for the AC
And if its 1 circuit no ground rod

A MWBC is considered one circuit in this case. Last sentence in 225.30

 

[Dennis Alwon]

I meant without physical protection. If I were to use the spiral-wrapped bare wire, or sleeve it, just how far away from each end's termination can that cover stop?

Larry if the GEC is #8 then it must be protected the entire way. 260.62(B) last sentence

 

[Jim W in Tampa]

Can we call it a single circuit even if it's supplying two separate 120v loads, like lights on one line and receptacles on the other?

We may decide to use a 4- or 6-space ML panel anyway, and install a few 15a breakers, which triggers the electrode requirements.

Without question if you install a 4 or 6 circuit panel the 2 rods are required. I would run this job in pvc if it will be one of them can we add . Many including myself start off thinking small loads and then end up wishing i had made it larger.
No reason not to share ditch other than not wanting the second rod in harms way.
As to protection of the ground rod wire i would think it be the same as required on the main building. The word protection is pretty much up to the inspector.

 

[LarryFine]

Larry if the GEC is #8 then it must be protected the entire way. 260.62(B) last sentence

Then how (to carry it to the extreme) do we terminate the #8?

 

[LarryFine]

Depends on if you call this 1 circuit or 2. Personally i see it as one circuit and a simple 2 pole 20 amp switch could be disconnect or a $ 10 pullout like you use for the AC

I would most likely use a 2p toggle switch.

If I do that, I can then use as many switches and receptacles on the load side of that switch as I want, as long as there are no breakers, right? It's the OCP that triggers the need for the electrodes?

 

[Dennis Alwon]

I would most likely use a 2p toggle switch.

If I do that, I can then use as many switches and receptacles on the load side of that switch as I want, as long as there are no breakers, right? It's the OCP that triggers the need for the electrodes?

The breaker has nothing to do with the requirement for an electrode. You could use a dp breaker if you wanted as long as there are no other circuits coming off the load side of the panel. I usually use a dp switch because it is cheaper but a pullout is pretty cheap also.

250.32 (A)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.

Then how (to carry it to the extreme) do we terminate the #8?

Do you mean at the ground rod? Obviously it would be exposed there but it would be below grade. :-?

 

[Jim W in Tampa]

I would most likely use a 2p toggle switch.

If I do that, I can then use as many switches and receptacles on the load side of that switch as I want, as long as there are no breakers, right? It's the OCP that triggers the need for the electrodes?

It's being more than 1 circuit that gets you into the rods. In what your suggesting i would call it 1 circuit because of the 2 pole breaker. Now your inspector might not agree. Is there any good reason you even need 2 circuits ? All sheds are not equal and some might be 500 sq ft with AC/HEAT,frig,welder ,etc.
Ground rods are never a bad idea but do add to cost.
Somehow your shed sounds like it might be more than just a shed.
I always point out to the home owner that PVC even if only 1 inch adds little to the cost and if upgrade ever needed will save you far more than what it cost now.