Grounding and Bonding at service?

[JasonCo]

Hey, I'm recently turned out and just trying to learn a thing or two in my spare time. My goal for this weekend is to learn a lot about grounding and bonding and draw out my diagrams of different scenarios so I can have them in my service van whenever I need to pull them out and refresh myself before a job. I wanted to see if I'm correct with my thinking on how to ground and bond.

Equipment used:
1. Meter
2. Fusible Disconnect
3. None fusible disconnect
4. Main panel
5. Sub panel

So let's say I have a 3-phase 120/240 Delta high leg service. Let's just say the raceways are none conductive (PVC). I would make sure there is a grounding electrode conductor bonded to the neutral at the load side of the service drop. The 4 wires come down from the weather head and into the meter can. Unsure if I need a grounding electrode to earth bonded to the neutral inside the meter can? From there I pull 4 wires from the meter and into fusible disconnect. Fusible disconnect 1 has to have the ground and neutral bonded together, and a grounding electrode must go to earth. Now I pull 5 wires (adding a EGC) to a none-fusible disconnect. At the none-fusible disconnect, I bond the EGC to the ground bar and the neutral is isolated and not bonded to the metal or anything. From here I pull 5 wires to the main panel inside/outside the building. Here I bond the neutral and ground together, and also (for example) drive a ground rod and bond both to a grounding electrode. Then from main panel to sub panel, I pull my 5 wires and in this sub panel, the neutral and ground bars are NOT bonded together, and the ground bar is bonded to the frame of the panel. No Grounding electrode to earth is required here.

Just wondering if I'm right or wrong with all this? Thanks a ton for any help or corrections you might have!

 

[Wire-Smith]

250.24(A)(1) your problem with meter base is if the connection is considered accessible, it is often not.

250.24(B) is disconnect 2 fed directly from meter base? or from disconnect 1? 230.71(A)

don't bond again in panel

 

[ActionDave]

Hey, I'm recently turned out and just trying to learn a thing or two in my spare time. My goal for this weekend is to learn a lot about grounding and bonding and draw out my diagrams of different scenarios so I can have them in my service van whenever I need to pull them out and refresh myself before a job. I wanted to see if I'm correct with my thinking on how to ground and bond.

Equipment used:
1. Meter
2. Fusible Disconnect
3. None fusible disconnect
4. Main panel
5. Sub panel

So let's say I have a 3-phase 120/240 Delta high leg service. Let's just say the raceways are none conductive (PVC). I would make sure there is a grounding electrode conductor bonded to the neutral at the load side of the service drop. The 4 wires come down from the weather head and into the meter can. Unsure if I need a grounding electrode to earth bonded to the neutral inside the meter can? From there I pull 4 wires from the meter and into fusible disconnect. Fusible disconnect 1 has to have the ground and neutral bonded together, and a grounding electrode must go to earth. Now I pull 5 wires (adding a EGC) to a none-fusible disconnect. At the none-fusible disconnect, I bond the EGC to the ground bar and the neutral is isolated and not bonded to the metal or anything. From here I pull 5 wires to the main panel inside/outside the building. Here I bond the neutral and ground together, and also (for example) drive a ground rod and bond both to a grounding electrode. Then from main panel to sub panel, I pull my 5 wires and in this sub panel, the neutral and ground bars are NOT bonded together, and the ground bar is bonded to the frame of the panel. No Grounding electrode to earth is required here.

Just wondering if I'm right or wrong with all this? Thanks a ton for any help or corrections you might have!

You never re bond the neutral after the first disconnect a.k.a Service Disconnect or the first disconnect of a Separately Derived System.

 

[roger]

IMO the meter is where the GEC should land and the service equipment only needs a Main Bonding Jumper.

Roger

 

[JasonCo]

250.24(A)(1) your problem with meter base is if the connection is considered accessible, it is often not.

250.24(B) is disconnect 2 fed directly from meter base? or from disconnect 1? 230.71(A)

don't bond again in panel

Disconnect 2 is fed directly from fused disconnect 1.

Appreciate the fast responses, giving it a good look now.

 

[Wire-Smith]

Disconnect 2 is fed directly from fused disconnect 1.

Appreciate the fast responses, giving it a good look now.

we appreciate you trying to learn this

 

[packersparky]

IMO the meter is where the GEC should land and the service equipment only needs a Main Bonding Jumper.

Roger

The utilities here will not allow the GEC to terminate in the meter enclosure.

 

[roger]

The utilities here will not allow the GEC to terminate in the meter enclosure.

And that makes no sense.

What lame reason do they give for not allowing it in your location?

Roger

 

[packersparky]

And that makes no sense.

What lame reason do they give for not allowing it in your location?

Roger

Some nonsense about not wanting a lightning strike to take our their meter. I know.......It makes no sense but what ya gonna do.

 

[Wire-Smith]

the reason here, is the accessibility. not that i agree with it, i think the sooner it grounds the grounded conductor the better. i'm not sure if they say anything about doing it at the mast.

 

[JasonCo]

You never re bond the neutral after the first disconnect a.k.a Service Disconnect or the first disconnect of a Separately Derived System.

So for example, I have a meter, I pull the hots and neutral from the meter to the disconnect. I bond the neutral to the GEC, while also adding a EGC and bonding them all together. Then I pull the EGC from disconnect to main panel. Main panel will have no bond between neutral and ground. Neutral is isolated, also no GEC is needed. Let's say this main panel is 277/480. I want to install a "sub-panel" 120/208. So I pull my 3 pole breaker (3 hots), with a neutral and EGC(?) down to the transformer. I bond the neutral and ground at the transformer, along with adding a GEC to the transformer. Then my sub-panel I will have to also bond the neutral and ground sense it is the start of a new separately derived system?

If this is correct, only thing I'm sort of not understanding is if I need a GEC at the meter? If so, do I just have a GEC or do I add a EGC as well. Feel like I've been getting mixed answers when I google this. Maybe not, idk I'm just confused about this part.

Thanks again for your help.

ohhhhh... I now see why I get mixed answers. So the utility company usually tags the meter with that tag lock (whatever you call it...), making it none accessible. So 250.24 (A)(1) would basically rule out the meter as being a good place for the GEC. Can I just say this then, I won't fail inspection if I just add the GEC and EGC to the disconnect 1 and call it a day?

 

[roger]

So for example, I have a meter, I pull the hots and neutral from the meter to the disconnect. I bond the neutral to the GEC, while also adding a EGC and bonding them all together. Then I pull the EGC from disconnect to main panel. Main panel will have no bond between neutral and ground. Neutral is isolated, also no GEC is needed. Let's say this main panel is 277/480. I want to install a "sub-panel" 120/208. So I pull my 3 pole breaker (3 hots), with a neutral and EGC(?) down to the transformer. I bond the neutral and ground at the transformer, along with adding a GEC to the transformer. Then my sub-panel I will have to also bond the neutral and ground sense it is the start of a new separately derived system?

You would not pull a neutral to the primary side of the transformer and you have to have a GEC to the secondary side since you have now derived a new system.

If this is correct, only thing I'm sort of not understanding is if I need a GEC at the meter?

You only need one GEC, (unless you have Separately Derived System down stream) it can be landed in the meter, the weather head, or the Main Service Equipment.

If so, do I just have a GEC or do I add a EGC as well. Feel like I've been getting mixed answers when I google this. Maybe not, idk I'm just confused about this part.

You will not have an EGC until after the main bonding jumper and it should land at the same location.

Thanks again for your help.

ohhhhh... I now see why I get mixed answers. So the utility company usually tags the meter with that tag lock (whatever you call it...), making it none accessible. So 250.24 (A)(1) would basically rule out the meter as being a good place for the GEC.

Not true, a POCO seal does not render it inaccessible and if it did what about the other conductors landed inside the meter can?

Can I just say this then, I won't fail inspection if I just add the GEC and EGC to the disconnect 1 and call it a day?

Probably.

Roger

 

[JasonCo]

You only need one GEC, (unless you have Separately Derived System down stream) it can be landed in the meter, the weather head, or the Main Service Equipment. You will not have an EGC until after the main bonding jumper and it should land at the same location.

So essentially whenever I bond my neutral to my EGC (whether it be at the meter or disconnect), that is where I will always land the GEC as well. I could either have the GEC at the meter, but that means I must bond my neutral and add a EGC and bond all 3 together at the meter. Or, just pull the hots and neutral from the meter to the disconnect. Then at the disconnect, bond a EGC to my Neutral and then also add and bond a GEC as well.

 

[roger]

So essentially whenever I bond my neutral to my EGC (whether it be at the meter or disconnect), that is where I will always land the GEC as well. I could either have the GEC at the meter, but that means I must bond my neutral and add a EGC and bond all 3 together at the meter. Or, just pull the hots and neutral from the meter to the disconnect. Then at the disconnect, bond a EGC to my Neutral and then also add and bond a GEC as well.

NO, the EGC is only concerned with the Main Bonding Jumper in the service equipment, that is where the EGC starts. The GEC is not part of the fault clearing path and can be bonded to the neutral in the meter.

Roger