Grounding all service switch neutrals without ground bus bar

[Tainted]

Typically in new installations I see all service switch neutrals being grounded to a common ground bus bar which connects to the building steel, ground rod, and water main.

How is it typically done without a ground bus bar? Old installations do not have ground bus bars.

 

[infinity]

Are you referring to GEC's from each service switch to a common ground bus which then connects to all of the electrodes?

 

[Tainted]

Are you referring to GEC's from each service switch to a common ground bus which then connects to all of the electrodes?

correct

 

[infinity]

So if you're not using a common bus then there are several options. One, is run a separate GEC from each service switch to each electrode (poor choice). Two, run a common GEC to the electrodes and tap off to each service switch with a split-bolt (slightly better choice). Three, run your GEC to a point ahead of all of the service switches and tap off to the other electrodes. I'm sure that there are others. If you have muliptle electrodes and service switches the bus bar seems to be the simplest option. That is generally what we use all of the time.

 

[Tainted]

So if you're not using a common bus then there are several options. One, is run a separate GEC from each service switch to each electrode (poor choice). Two, run a common GEC to the electrodes and tap off to each service switch with a split-bolt (slightly better choice). Three, run your GEC to a point ahead of all of the service switches and tap off to the other electrodes. I'm sure that there are others. If you have muliptle electrodes and service switches the bus bar seems to be the simplest option. That is generally what we use all of the time.

I know raceways can be used as a equipment grounding conductors but can raceways be used as a grounding electrode conductor?

 

[ActionDave]

I know raceways can be used as a equipment grounding conductors but can raceways be used as a grounding electrode conductor?

I guess if it was rigid aluminium it would be possible based on -

250.62 Grounding Electrode Conductor Material

The grounding electrode conductor shall be of copper, aluminum, copper-clad aluminum

but I don't know how you would size it since 250.66 only uses wire gauges.

 

[Tainted]

I guess if it was rigid aluminium it would be possible based on -



but I don't know how you would size it since 250.66 only uses wire gauges.

Interesting.

You can argue and say table 250.122 for equipment grounding conductors uses wire gauges too yet we're allowed to use raceways instead of wires

 

[Tainted]

Three, run your GEC to a point ahead of all of the service switches and tap off to the other electrodes.

If I run my GEC to a point ahead of all the service switches, does this mean the service switches must not have a main bonding jumper and GEC?

 

[infinity]

If I run my GEC to a point ahead of all the service switches, does this mean the service switches must not have a main bonding jumper and GEC?

No GEC required just a MBJ in each switch.

 

[Tainted]

No GEC required just a MBJ in each switch.

Hmmm is there an illustration of this? Maybe I’m misunderstanding

 

[infinity]

Hmmm is there an illustration of this? Maybe I’m misunderstanding

The system neutral is connected to the GEC which is connected to the electrodes. That connection point can be anywhere between the service point (typically where the utility connects) and the service disconnects. Once the neutral is connected upstream of the service disconnects it is not required to be connected again at each service disconnect. A MBJ is required at each service disconnect because there is no EGC after the service disconnect if the neutral is not bonded.

 

[Tainted]

The system neutral is connected to the GEC which is connected to the electrodes. That connection point can be anywhere between the service point (typically where the utility connects) and the service disconnects. Once the neutral is connected upstream of the service disconnects it is not required to be connected again at each service disconnect. A MBJ is required at each service disconnect because there is no EGC after the service disconnect if the neutral is not bonded.

I see, I drew it out and it made more sense, thank you.

 

[Phil Timmons]

Typically in new installations I see all service switch neutrals being grounded to a common ground bus bar which connects to the building steel, ground rod, and water main.

How is it typically done without a ground bus bar? Old installations do not have ground bus bars.

Great Question. I am seeing this as maybe a Best Practices questions -- instead or maybe more than "just" a "Minimal Code Requirement" question.

Is there any practical or code limitation AGAINST adding a Ground Bus Bar?