grounding at sub panel

[enireh]

I'm on a farm with four subpanels. All of them have three wires feeding them. They are all over 100' from the main panel underground. The owner doesn't want to spend the time or money pulling a ground. I was thinking about driving a ground rod at each sub panel

 

[iwire]

This is normal for old buildings

The code allows it to remain but it must be set up like a service with the neutral bonded to the enclosure and a grounding electrode system. Going from memory see 250.30 or 32 for details

 

[PSpear]

Mixed answers

Mixed answers

I have been told two different answers on that subject from two different inspectors. One told me there needs to be 4 wires feeding every sub panel, the other telling me three with a ground rod. So the best bet is to check with the Inspector for where ever you are. Personally if it only has a three wire feed then you NEED a ground rod.

 

[iwire]

I have been told two different answers on that subject from two different inspectors. One told me there needs to be 4 wires feeding every sub panel, the other telling me three with a ground rod. So the best bet is to check with the Inspector for where ever you are. Personally if it only has a three wire feed then you NEED a ground rod.

Forget what you where told and look up the rules in 250.30 or 32. One of those sections explains it.

 

[ActionDave]

Forget what you where told and look up the rules in 250.30 or 32. One of those sections explains it.

Pretty good memory. It's 250.32.

I have been told two different answers on that subject from two different inspectors. One told me there needs to be 4 wires feeding every sub panel, the other telling me three with a ground rod. So the best bet is to check with the Inspector for where ever you are. Personally if it only has a three wire feed then you NEED a ground rod.

Either answer is correct, pre 2005 you did not always need an Equipment Ground.

I'm on a farm with four subpanels. All of them have three wires feeding them. They are all over 100' from the main panel underground. The owner doesn't want to spend the time or money pulling a ground. I was thinking about driving a ground rod at each sub panel

Are you sure there is not a ground rod or another acceptable grounding electrode like building steel already in place?

The ground rod is less important than making sure the neutral is bonded at each panel.

 

[iwire]

The ground rod is less important than making sure the neutral is bonded at each panel.

I cannot agree more.

Make sure the bonding is done

 

[ggunn]

I'm on a farm with four subpanels. All of them have three wires feeding them. They are all over 100' from the main panel underground. The owner doesn't want to spend the time or money pulling a ground. I was thinking about driving a ground rod at each sub panel

I'm pretty sure that the NEC now requires a ground wire but has an exception that says if it was built to code at the time it's OK to leave it as is. You do need the ground rods, though.