Length of Ground Wire

[spam4us]

Hello,

I will be installing a 90A sub-panel in my detached pole building garage.

When I run the ground wire to the 2 rods, how long of a run can it be?

I'd like to put the ground rods about 50 feet away from the panel and run the ground wire inside of the interior wall then exit it to the rods that will be outside.

Can I just drill a whole thru the metal wall panel to run the wire to the outside rods or is there a neater way?

Lastly, does the sub-panel main breaker need to be at a particular height off the ground?

Thanks

 

[zmaxmotorsports]

Youll be fine ,I normally set top of any panel at 6' myself.

 

[kd3pc]

gnd should be shortest, straightest path you can.

 

[n8n]

If it is a sub panel you need to run ground back to main panel with the service cable. If you add rods for the outbuilding those are supplemental only. Also ground and neutral busses must be separate at the sub panel and neutral ungrounded.

 

[alfredeneuman]

By Code:
The center of the circuit breaker's operating switch cannot be more than 6'7" off the floor when in its highest operating position.

There is no minimum height requirement.

 

[wyliesdiesels]

I do a lot of R56 grounding at work. U want the wire as short and as straight as possible! Gradual bends if necessary!

If it is a sub panel you need to run ground back to main panel with the service cable. If you add rods for the outbuilding those are supplemental only. Also ground and neutral busses must be separate at the sub panel and neutral ungrounded.

you might consider them supplementary but they ARE required for a detached structure...

 

[spam4us]

Thanks everyone for your help. Just so I have this straight.....

This is a detached garage.
I'm using a 100A panel that has a 100A main breaker. This main breaker should be no higher than 6'7" from the ground.

I am using 2-2-2-4 mhf back to my main panel that I will connect to a 90A breaker.

In the sub panel, I will remove the green bonding screw so that the neutral and ground are isolated from each other.

I will then run a #4 copper ground from the ground bar in the sub-panel to the 2 grounding rods.

Where the ground wire connects to the ground rods....does this connection need to be above the ground or can I pound the rod just below the surface and make the connection there?

The ground rods will be on the exteror of the building 6 ft apart. Does the ground wire have to be protected(conduit) where it goes from one rod to the other?

Thanks

 

[wyliesdiesels]

Thanks everyone for your help. Just so I have this straight.....

This is a detached garage.
I'm using a 100A panel that has a 100A main breaker. This main breaker should be no higher than 6'7" from the ground.

I am using 2-2-2-4 mhf back to my main panel that I will connect to a 90A breaker.

In the sub panel, I will remove the green bonding screw so that the neutral and ground are isolated from each other.

I will then run a #4 copper ground from the ground bar in the sub-panel to the 2 grounding rods.

Where the ground wire connects to the ground rods....does this connection need to be above the ground or can I pound the rod just below the surface and make the connection there?

The ground rods will be on the exteror of the building 6 ft apart. Does the ground wire have to be protected(conduit) where it goes from one rod to the other?

Thanks

The largest size wire u need is solid #6 cu. #4 is overkill...

u can make the connection below grade.

And as long as the wire isnt subject to damage(weed wacker, mower etc.), then no protection is needed...

 

[zmaxmotorsports]

The largest size wire u need is solid #6 cu. #4 is overkill...

u can make the connection below grade.

And as long as the wire isnt subject to damage(weed wacker, mower etc.), then no protection is needed...

 

[ddawg16]

The largest size wire u need is solid #6 cu. #4 is overkill...

u can make the connection below grade.

And as long as the wire isnt subject to damage(weed wacker, mower etc.), then no protection is needed...

Make sure you use clamps rated for below ground. Most are...but you will find some that are not.

Typically you put it all below grade....leave it exposed for the inspector...once he buys off...cover it up.