Ground conductor or no?

[hardworkingstiff]

Here is the scenario:

Meterbase will be installed a couple of hundred feet from the begining of the fixed pier. An enclosed circuit breaker will be installed adjacent to the meterbase (disconnect 1). Another enclosed circuit breaker will be installed at the beginning of the fixed pier (disconnect 2). A 400-amp MLO panel will be installed out on the fixed pier and fed from disconnect 2. Parrallel 4/0 conductors will be pulled from the meterbase to disconnect 1 then to disconnect 2 then to the MLO panel.

Here's the questions:

Do you need to pull a ground conductor between disconnect 1 and 2, or can you ground the neutral at disconnect 2 and call it the service disconnect?

 

[don_resqcapt19]

The 2008 code requires that you install an EGC. The older codes may require an EGC if there are other conductive paths between the first disconnect and the dock.

 

[Dennis Alwon]

Once you leave the main service panel-- pole one I would vote that you need an egc between poles and also to the pier. I will go one step further and say you need a max of 6 discos or a main at the pier. Ground rods at all points are also necessary since I see each post as a separate structure

 

[hardworkingstiff]

I will go one step further and say you need a max of 6 discos or a main at the pier.

I thought you only needed a main (in this scenario) if the MLO was a lighting panel.

 

[Dennis Alwon]

I thought you only needed a main (in this scenario) if the MLO was a lighting panel.

The lighting panel has been removed from the code. 6 discos max. or a main disco. But it always has been no more than s throws to disconnect a structure.

 

[augie47]

...........................................Do you need to pull a ground conductor between disconnect 1 and 2, or can you ground the neutral at disconnect 2 and call it the service disconnect?

unable to overcome my SA desire this morning,my first answer would be based on the term "ground condcutor", but I believe you are questioning the requirement for a "equipment gounding conductor", is that correct ?

The answer, to me, was somewhat hazy prior to to 2008 depending on
if one considered disconnect #2 to be mounted on an "seperate structure"
(and the Code definition of structure). As of 2008 Code, 250.32 makes the answers yes..equipment grounding conductor needed.

 

[Pierre C Belarge]

Once you leave the main service panel-- pole one I would vote that you need an egc between poles and also to the pier. I will go one step further and say you need a max of 6 discos or a main at the pier. Ground rods at all points are also necessary since I see each post as a separate structure

The pier is a "structure" as per Article 100, and most building code definitions.

If disconnects # 2 & 3 are mounted on the piers, they are all mounted on 1 structure. That would necessitate the need for standard wiring between the panel 2 & 3, including a means for an equipment ground conductor. Also if I understand you correctly, the need for main breakers at the "sub-panel (#3)" would not be necessary.

Depending on which version of the NEC would determine which wiring methods as per 250.32 would be permitted, and the associated grounding required.

Since this is premise wiring, the disconnect at the meter location is the service disconnecting means, all other disconnects are "subpanels".
References are 250.32 and Article 225, Part II.

 

[hardworkingstiff]

unable to overcome my SA desire this morning,my first answer would be based on the term "ground condcutor", but I believe you are questioning the requirement for a "equipment gounding conductor", is that correct ?

Yes, that's what I mean.

The answer, to me, was somewhat hazy prior to to 2008 depending on
if one considered disconnect #2 to be mounted on an "seperate structure"
(and the Code definition of structure). As of 2008 Code, 250.32 makes the answers yes..equipment grounding conductor needed.

I was afraid of that. If we did not have a disconnect at the meterbase, then I believe disconnect 2 would become the service disconnect and all grounding of the neutral could be done there with no requirement of a equipment grounding conductor to be pulled? The thing I don't care for in the scenario is the only overcurrent protection for the service lateral would be the primary fuse on the PoCo transformer. They do it all the time though.