[Bythepond88]

In the process of restoring power to my garage dealt with in another thread, I discovered that there is no ground connection back to the house panel. The previous owner had run a two conductor UF cable without a ground wire.

Can I install a ground rod next to the garage foundation and hook to that? Or do I have to run a complete new cable from the house panel to the garage. The cable would have to go under a sidewalk, so I'd rather not go that route if there's a safe alternative.

 

[Jim Port]

How much capacity do you need at the shed? Do you need any 240 volt loads? Is there any metallic path back to the house?

 

[Bythepond88]

No, I do not need any 240v load. I will just be running a light over the bench, the garage door opener, and the occasional hand power tool, and maybe a planer for short periods from time to time. (Not all at once, of course.)

 

[rjniles]

There is no approved way correct this without running a new cable.

If you wish to continue using what you have, add a GFCI receptacle at the first appearance of the UF cable and feed the rest of the garage off the load terminals.

 

[Arrow3030]

A ground rod in this scenario would be more likely to shock someone than open a circuit breaker. Electricity isn't trying to go to earth. GFCI protection is the best option besides running a new cable.

 

[Bythepond88]

Can I install a GFCI without a separate ground wire?

 

[rjniles]

Can I install a GFCI without a separate ground wire?

GFCI does not require a ground to operate. It senses an unbalance between the hot and neutral.

 

[Bythepond88]

Thanks for the advice. I'll go with a GFCI, then.

 

[Know A Little]

A ground rod in this scenario would be more likely to shock someone than open a circuit breaker. Electricity isn't trying to go to earth. GFCI protection is the best option besides running a new cable.

Actually what he has is basically a separate service much like what the utility runs to any residence except in lieu of 240/120 3 wire he has 120 2 wire. He can and most likely should install a circuit breaker panel and drive a ground rod grounding the neutral. He should still utilize the GFCI.

 

[Know A Little]

A ground rod in this scenario would be more likely to shock someone than open a circuit breaker. Electricity isn't trying to go to earth. GFCI protection is the best option besides running a new cable.

DIY would not let me use the EDIT feature for some reason.

Can you explain how you think a ground rod could make this installation more of a shock hazard?

 

[rjniles]

Actually what he has is basically a separate service much like what the utility runs to any residence except in lieu of 240/120 3 wire he has 120 2 wire. He can and most likely should install a circuit breaker panel and drive a ground rod grounding the neutral. He should still utilize the GFCI.

Not sure what the value would be. More money with no benefit.

 

[Arrow3030]

If it were like a service entrance and the neutral was bonded to the EGC'S and the ground rod than there's not likely a shock hazard.
It's when EGC's are not bonded to a grounded conductor and only a ground rod when things are fundamentally wrong. *Drive a ground rod, hook up 120v to it on a 20A breaker and see what happens.
*hypothetical

 

[Know A Little]

Not sure what the value would be. More money with no benefit.

No benefit in having a grounded system?

 

[Know A Little]

If it were like a service entrance and the neutral was bonded to the EGC'S and the ground rod than there's not likely a shock hazard.
It's when EGC's are not bonded to a grounded conductor and only a ground rod when things are fundamentally wrong. *Drive a ground rod, hook up 120v to it on a 20A breaker and see what happens.
*hypothetical

I said treat it like a SDS. Safer based on over a 140 years experience.

 

[Arrow3030]

I'm not sure what your point is. Maybe it would help if I was more concise. A ground rod doesn't clear a fault, that's not why it's installed. Electricity takes any path available back to its source including earth. The earth has resistance. Applying voltage to earth can be dangerous. Ground rods are used to establish a connection to earth.

 

[rjniles]

No benefit in having a grounded system?

Only if it is bonded to a service neutral.

 

[Bythepond88]

I'm not trying to clear a fault, I'm just trying to make it so that I can properly wire a three wire plug for tools. Currently, I have a two conductor feeder wired to a 20A breaker in the house panel.

Know a Little, are you saying that I should install a sub panel in the garage, and connect the ground conductor to that somehow?

If I do go that route, next question is do I have to fish a ground wire to each box, or can I ground the outlets to the boxes and use the conduit as the ground path to the panel? I've heard of doing that, but was never sure if it was safe.

 

[Arrow3030]

You are trying to clear a fault when a 3 wire plug is properly installed. It's one of the two functions of the "third conductor " (called an equipment grounding conductor or layman term "ground wire"). A metal conduit system can be an EGC.
In your case I'd recommend the GFCI as RJ suggested and not bother with a panel and ground rod. As RJ stated, it's waisted time and material IMO.

 

[rjniles]

I'm not trying to clear a fault, I'm just trying to make it so that I can properly wire a three wire plug for tools. Currently, I have a two conductor feeder wired to a 20A breaker in the house panel.

Know a Little, are you saying that I should install a sub panel in the garage, and connect the ground conductor to that somehow?

If I do go that route, next question is do I have to fish a ground wire to each box, or can I ground the outlets to the boxes and use the conduit as the ground path to the panel? I've heard of doing that, but was never sure if it was safe.

The purpose of the ground is to clear a fault. A ground rod will not do it.

 

[Know A Little]

I'm not sure what your point is. Maybe it would help if I was more concise. A ground rod doesn't clear a fault, that's not why it's installed. Electricity takes any path available back to its source including earth. The earth has resistance. Applying voltage to earth can be dangerous. Ground rods are used to establish a connection to earth.

I never said it did BUT if you are going to bond the neutral (maybe a two circuit panel) and end up with a 2-wire grounded system, which I feel is a better approach from a safety stand point, A GROUNDED SYSTEM. you have to install the ground rods.


Do the grounds do anything, YES they comply with the NEC, are the critical to the operation of the circuit or over current protection devices , Heck no.