GEC tap continuous

[Electricwiring81]

Hello all,
My question is in regards to the GEC and tapping for a second non-fused disconnect ahead of main service disconnect. We installed a solar system with battery and plans called for a non-fused disconnect ahead of MCB. My boss told me to come off the GEC. Plans don’t call for the neutral/ground bonded at disconnect. I arrived at job and noticed no ground rods, which our engineered plans shows. There appears to be a UFER ground already and I know ground rods aren’t required. My boss wanted them put in anyways. He had me irreversibly crimp onto the UFER ground after the point of its connection and then install the ground rods. I went ahead and ran the extended ground from the ground rods to the non-fused disconnect continuously. I know you are allowed to use a split bolt or irreversible crimp but instead, just kept my new run continuing to the non-fused disconnect. Does anyone see an issue with this. My boss says it’s fine but I’d like more input because this whole non fused disconnect ahead of MCB is new to me.

 

[Elect117]

The lack of fusing seems odd to me as well. I would take a look at 705.11(C) which is the overcurrent protection requirements for supply-side source connections. 230.82 is also pretty specific about the need for protection when making supply side connections for interconnected power production systems. The only competing section is 706.31(D) exception which has pretty broad language. I can't tell if that is where the decision came from.

As for the grounding, you can also take a look at grounding electrode systems and watch a video on youtube from Mike Holt on how it works. I can't tell if the two rods and the ufer ground were properly installed to make it one system. Maybe they are trying meet 250.169? But I don't think can install it as separately derived if your bonding point is on the AC side of an inverter. Maybe someone else has more insight on that.

 

[Electricwiring81]

The lack of fusing seems odd to me as well. I would take a look at 705.11(C) which is the overcurrent protection requirements for supply-side source connections. 230.82 is also pretty specific about the need for protection when making supply side connections for interconnected power production systems. The only competing section is 706.31(D) exception which has pretty broad language. I can't tell if that is where the decision came from.

As for the grounding, you can also take a look at grounding electrode systems and watch a video on youtube from Mike Holt on how it works. I can't tell if the two rods and the ufer ground were properly installed to make it one system. Maybe they are trying meet 250.169? But I don't think can install it as separately derived if your bonding point is on the AC side of an inverter. Maybe someone else has more insight on that.

I’ve read the articles you mentioned and I think those articles don’t necessarily apply to the grounding situation. We have overcurrent protection down the line for sources of power. My main concern is having the disconnect connected in one continuous piece through the ground rods and back to the UFER. I don’t know if the non fused safety switch being at the end of the system or tapping somewhere along the middle of system makes a difference? The GEC wire is rated for the incoming ungrounded wiring like it should in 250.66. Most times when I see people discussing taps it’s right near the meter but this application doesn’t really work with that because the GEC isn’t easily accessible at that point . This safety switch is installed for POCO so they can turn off system on their side. They specifically require it.

 

[jaggedben]

I'm really confused. The poco required a non-fused disconnect? Does this then lead directly to a suitable-for-use-as-service-equipment overcurrent device for your system?

The non-fused disco may violate NEC requirements for interrupting ratings, and I realize that's a whole other issue than what you asked about. But if you don't already have a proper disconnect and overcurrent protection then that's a major issue. Diagram?

Supposing you have a proper service disconnect somewhere, I'm trying to figure out if you treat the non-fused disco as a service disconnect or just ignore it because it's a poco requirement than has no real NEC significance. Like, can you call it a 'meter disconnect'? If it's a 'meter disconnect' then that's something the NEC allows and also allows you to otherwise ignore. So bring your new GEC tap to your other service equipment for your system.

To address your actual question, the NEC does not actually say that GEC taps to multiple service disconnects have to be irreversible or continuous. (250.64(D)) I think a Kearny bolt would be compliant.

I'm also unclear what you did with the rods. Best practice would be to connect the rods to the UFER GEC near the ground and the GEC tap to your new disco near the discos. I.e. all grounding connections still go through the single line of the existing GEC. I agree the rods aren't required but maybe your boss has experience with inspectors not accepting the existence of Ufers that don't have permit records.

It used to be controversial how to ground and bond a supply side connection but since the 2020 NEC it is much more clear that you treat it like an additional service disconnect.

 

[Electricwiring81]

Jaggedben, my boss has had these installed previously and both electrical inspectors and poco have signed off on them. My main issue is whether hitting the UFER, the ground rods and then my non-fused disconnect is an issue( that specific order)? Does location of tap along system matter? I haven’t seen any real clear answer on this from code. They only tell you if you do a tap it has to be a listed connector, irreversible, or off a copper bar.

 

[jaggedben]

I'm still not 100% sure I understand what you did but it sounds NEC compliant. Each service disconnect can have its own GEC to the electrodes. It's just not necessarily best practice to create those ground loops.

 

[tom baker]

I'm still not 100% sure I understand what you did but it sounds NEC compliant. Each service disconnect can have its own GEC to the electrodes. It's just not necessarily best practice to create those ground loops.

Why is it a ground loop? The GEC is not normally current carrying.

 

[jaggedben]

GEC normally *is* current carrying, to some degree, but even if it were not then a loop (and parallel neutral path) would be:
Neutral bar in service disconnect #1> Ufer GEC > bonding jumper to rods > GEC to service disconnect #2 > neutral bar in service disconnect #2 > neutral and raceways bonded to neutral between service disconnects #1 and #2 > back to start

Also I think Mike Holt would tell you this is not the best way to do it in lightning prone areas, provides a path for lighting discharge to travel between electrodes via the servife equipment. Better would be to have taps to service disconnects come to a single GEC, which goes to ground and branches out to electrodes. Then lightning discharge travelling via bonding jumpers between electrodes doesn't have a path through service equipment.

 

[Electricwiring81]

Jaggedben, my boss has had these installed previously and both electrical inspectors and poco have signed off on them. My main issue is whether hitting the UFER, the ground rods and then my non-fused disconnect is an issue( that specific order? Does location of tap along system matter? I haven’t seen any real clear answer on this from code. They only tell you if you do a tap it has to be a listed connector, irreversible, or off a copper bar.

GEC normally *is* current carrying, to some degree, but even if it were not then a loop (and parallel neutral path) would be:
Neutral bar in service disconnect #1> Ufer GEC > bonding jumper to rods > GEC to service disconnect #2 > neutral bar in service disconnect #2 > neutral and raceways bonded to neutral between service disconnects #1 and #2 > back to start

Also I think Mike Holt would tell you this is not the best way to do it in lightning prone areas, provides a path for lighting discharge to travel between electrodes via the servife equipment. Better would be to have taps to service disconnects come to a single GEC, which goes to ground and branches out to electrodes. Then lightning discharge travelling via bonding jumpers between electrodes doesn't have a path through service equipment.

GEC normally *is* current carrying, to some degree, but even if it were not then a loop (and parallel neutral path) would be:
Neutral bar in service disconnect #1> Ufer GEC > bonding jumper to rods > GEC to service disconnect #2 > neutral bar in service disconnect #2 > neutral and raceways bonded to neutral between service disconnects #1 and #2 > back to start

Also I think Mike Holt would tell you this is not the best way to do it in lightning prone areas, provides a path for lighting discharge to travel between electrodes via the servife equipment. Better would be to have taps to service disconnects come to a single GEC, which goes to ground and branches out to electrodes. Then lightning discharge travelling via bonding jumpers between electrodes doesn't have a path through service equipment.

There is only the one safety witch fed from meter and then after the safety switch is the MOP. The neutral isn’t bonded at safety switch, it simply passes through. My boss wanted me to come off of GEC to bond safety switch enclosure. Says this is what he has always done. Neutral and ground are bonded at MOP.

 

[texie]

Jaggedben, my boss has had these installed previously and both electrical inspectors and poco have signed off on them. My main issue is whether hitting the UFER, the ground rods and then my non-fused disconnect is an issue( that specific order? Does location of tap along system matter? I haven’t seen any real clear answer on this from code. They only tell you if you do a tap it has to be a listed connector, irreversible, or off a copper bar.


There is only the one safety witch fed from meter and then after the safety switch is the MOP. The neutral isn’t bonded at safety switch, it simply passes through. My boss wanted me to come off of GEC to bond safety switch enclosure. Says this is what he has always done. Neutral and ground are bonded at MOP.

I'm not clear about why the switch is needed, but I can say that if it is on the line side of the main service disconnect then it must be bonded in a manner compliant with 250.92 like any other metallic item on the line side. The GEC has nothing to do with 250.92 and can not be used to meet 250.92 requirements.

 

[Electricwiring81]

I'm not clear about why the switch is needed, but I can say that if it is on the line side of the main service disconnect then it must be bonded in a manner compliant with 250.92 like any other metallic item on the line side. The GEC has nothing to do with 250.92 and can not be used to meet 250.92 requirements.

So would coming off the MOP and heading back with ground wire hitting the bonding lug be the correct way? Sized according to table 250.102c(1).
Would another option be the 2020 NEC art 230.82(3) allowing us to simply bond the neutral at this first safety switch calling it an “Emergency Diconnnect” and then bond again at service disconnect? The 2020 code just got adopted here and there is confusion among contractors and inspectors on this particular section of code.

 

[Electricwiring81]

So would coming off the MOP and heading back with ground wire hitting the bonding lug be the correct way? Sized according to table 250.102c(1).
Would another option be the 2020 NEC art 230.82(3) allowing us to simply bond the neutral at this first safety switch calling it an “Emergency Diconnnect” and then bond again at service disconnect? The 2020 code just got adopted here and there is confusion among contractors and inspectors on this particular section of code.

Art. 230.85 not 230.82 my apologies.Don’t have my code book in front of me at moment.

 

[texie]

So would coming off the MOP and heading back with ground wire hitting the bonding lug be the correct way? Sized according to table 250.102c(1).
Would another option be the 2020 NEC art 230.82(3) allowing us to simply bond the neutral at this first safety switch calling it an “Emergency Diconnnect” and then bond again at service disconnect? The 2020 code just got adopted here and there is confusion among contractors and inspectors on this particular section of code.

Yes to both options.
But for me, there are questions as to why this switch is there at all between the meter and service disconnect. At best this switch should be marked "Not Service Equipment". Note that this is usually used only where you have a meter disconnect ahead of the meter and the NEC allows for such. AKA cold sequence metering.

 

[texie]

Art. 230.85 not 230.82 my apologies.Don’t have my code book in front of me at moment.

Noted.

 

[electrofelon]

. The neutral isn’t bonded at safety switch, it simply passes through. My boss wanted me to come off of GEC to bond safety switch enclosure. Says this is what he has always done. Neutral and ground are bonded at MOP.

A few more specifics are needed before I bash your boss, but it sounds like he may need to go back to school.

Jaggedben, my boss has had these installed previously and both electrical inspectors and poco have signed off on them.

Just keep in mind the majority of people in the electrical industry, even many inspectors, dont know code that well

 

[hornetd]

But for me, there are questions as to why this switch is there at all between the meter and service disconnect. At best this switch should be marked "Not Service Equipment". Note that this is usually used only where you have a meter disconnect ahead of the meter and the NEC allows for such. AKA cold sequence metering.

The 2020 requirement for an Emergency Disconnect specifically says that it does not have to be the Service Disconnect. It goes on to state how it must be marked. The mystery to me is why your electrical utility requires it and is that requirement in the State's Utility regulating agency's approved copy of the utility's service standard. All changes to service standards must be approved by the State's Electrical Utility Regulating Agency. Any requirement that is not on the State's regulatory agency's approved copy can be ignored. Trouble is that will mean that you will have to get an Order To Connect from the State's regulatory agency ordering the utility to connect your service because it complies with all Regulatory Agency Approved Service Standard. The delay in getting power connected is what often causes the contractor to comply with unapproved Service Requirements.

Tom Horne