OMG! Yes..same guy then.
Am looking for some electrical code help
- Thread starter LBen
- Start date
Have been gone a long while, so here is where I'm at for those that are interested.
I went to a DIY electrical forum and some suggestions were made that gave me a path forward. I will have an exterior wireway/gutter/trough mounted horizontally and an interior wireway/gutter/trough mounted vertically. This lets me handle the incoming grid feed interconnections with the stuff on the exterior wall along with getting power to the main panel. I was brain locked - but after the suggestion on the electrical forum it is simple. Complexity is having to cut a pair of 2.5" EMT through a concrete wall to join the two wireways together. I've got room for 3.5" holes in the concrete to hit both wireways - just barely.
All paperwork is done. PoCo approved installation, county took 4 weeks to issue the permit and the Colorado state permit portal has solar as an afterthought. After several days was able to talk with a state rep in Denver and he generated the permit app using their standard online forms. I did not think the forms used for house wiring would have been applicable - but that is what he used and just added solar specific notes on the app.
Did I say that my site was rocky???
One week of work with my 38 hp tractor/BH carved a shelf out of a hillside for the Sinclair ballasted ground mount. A couple areas required pickaxe work to knock down a granite ledge that I had uncovered. Then I had to bring in 20 ton of gravel to get everything levelled out for the ballast blocks. Picture attached.
I have 215' of 2" PVC conduit in a trench to run the PV wire to the house. What a beetch. Gas powered trencher was bucking and jumping as it popped out 6" rock in some places. Rental place would not have been happy if they saw what was being cut through. Some of this was on a 15 deg slope. Got the trencher stuck a couple times and had to drag it to a better position with the tractor. In another area had to back the tractor down the slope and use the BH to gnaw through decomposed granite to cut the trench. Also had to resort to pickaxe in one area to knock a slightly deeper trench to get the pvc down deep enough. I had to cover a couple portions of the trench to allow my tractor to get into where I could put in ground plates and another to allow the cement truck room to get turned in. Inspector probably won't like that.
Solar mount grounding - did I say I have rocks? Tried driving 3/4" rebar in a couple of places before I committed a ground rod. After 4 attempts got the rebar down about 2' in one place. So moved to the ground rod. Manual post driver got me another foot. Got ticked off and got out my gas post driver. Got down another foot and the rod stopped - gas post driver was just jumping around on the rod. Plan B. Used the BH to try to dig two 30" deep holes for ground plates. First one went ok, but was digging through a lot of pretty hard decomposing granite. Move to second hole. After about 20" the going got real hard. Having to chip through the rock with the teeth of the BH bucket. Even though the front bucket was set hard into the ground and the BH out riggers were supporting the back of the tractor, I was putting a large enough load on the BH to pull the tractor backwards down the slope - until a tree blocked the movement. Finally blew a hydraulic hose. After the hose repair another hours worth of work to get down to 30+ inches for the ground plate.
None of the electrical places in Pueblo or Colorado Springs have heard of ground plates. So had to order from Gordon Electric in Illinois.
Two concrete contractors have defacto bailed on me. On initial contact they wanted to do the job, but after a couple phone calls discussing the basics they went quiet. No replies to phone calls, messages or texts. Typical Fremont county contractors. Did luck out with another guy. Called on Friday, he looked at things Monday, scheduled for the pour on Thursday. County did their hole/rebar inspection last week.
I've got about 20k in solar hardware on site currently. Had to go to Pueblo today to pick up approx 2000' of wire for this project. WIre was shipped LTL, but I've had dealings with the trucking firm in Pueblo, so to minimize the aggravation, I just did a 150 mile round trip and picked it up at the terminal. With all the complications that have happened, I'm about 2 months behind where I wanted to be. Even though it is pretty hot right now, we have had snow in September in previous years. I sure as heck want to get all the outside work done by mid September.
Months ago I was doubting my sanity in doing this project. I do believe that I am now certified crazy. Maybe more beer will fix things.
Oh, and on the question I thought I had, driving back from Pueblo today I think I figured out way of getting the big EMT fittings connected to the EMT in the wall.
Lowell
I went to a DIY electrical forum and some suggestions were made that gave me a path forward. I will have an exterior wireway/gutter/trough mounted horizontally and an interior wireway/gutter/trough mounted vertically. This lets me handle the incoming grid feed interconnections with the stuff on the exterior wall along with getting power to the main panel. I was brain locked - but after the suggestion on the electrical forum it is simple. Complexity is having to cut a pair of 2.5" EMT through a concrete wall to join the two wireways together. I've got room for 3.5" holes in the concrete to hit both wireways - just barely.
All paperwork is done. PoCo approved installation, county took 4 weeks to issue the permit and the Colorado state permit portal has solar as an afterthought. After several days was able to talk with a state rep in Denver and he generated the permit app using their standard online forms. I did not think the forms used for house wiring would have been applicable - but that is what he used and just added solar specific notes on the app.
Did I say that my site was rocky???
One week of work with my 38 hp tractor/BH carved a shelf out of a hillside for the Sinclair ballasted ground mount. A couple areas required pickaxe work to knock down a granite ledge that I had uncovered. Then I had to bring in 20 ton of gravel to get everything levelled out for the ballast blocks. Picture attached.
I have 215' of 2" PVC conduit in a trench to run the PV wire to the house. What a beetch. Gas powered trencher was bucking and jumping as it popped out 6" rock in some places. Rental place would not have been happy if they saw what was being cut through. Some of this was on a 15 deg slope. Got the trencher stuck a couple times and had to drag it to a better position with the tractor. In another area had to back the tractor down the slope and use the BH to gnaw through decomposed granite to cut the trench. Also had to resort to pickaxe in one area to knock a slightly deeper trench to get the pvc down deep enough. I had to cover a couple portions of the trench to allow my tractor to get into where I could put in ground plates and another to allow the cement truck room to get turned in. Inspector probably won't like that.
Solar mount grounding - did I say I have rocks? Tried driving 3/4" rebar in a couple of places before I committed a ground rod. After 4 attempts got the rebar down about 2' in one place. So moved to the ground rod. Manual post driver got me another foot. Got ticked off and got out my gas post driver. Got down another foot and the rod stopped - gas post driver was just jumping around on the rod. Plan B. Used the BH to try to dig two 30" deep holes for ground plates. First one went ok, but was digging through a lot of pretty hard decomposing granite. Move to second hole. After about 20" the going got real hard. Having to chip through the rock with the teeth of the BH bucket. Even though the front bucket was set hard into the ground and the BH out riggers were supporting the back of the tractor, I was putting a large enough load on the BH to pull the tractor backwards down the slope - until a tree blocked the movement. Finally blew a hydraulic hose. After the hose repair another hours worth of work to get down to 30+ inches for the ground plate.
None of the electrical places in Pueblo or Colorado Springs have heard of ground plates. So had to order from Gordon Electric in Illinois.
Two concrete contractors have defacto bailed on me. On initial contact they wanted to do the job, but after a couple phone calls discussing the basics they went quiet. No replies to phone calls, messages or texts. Typical Fremont county contractors. Did luck out with another guy. Called on Friday, he looked at things Monday, scheduled for the pour on Thursday. County did their hole/rebar inspection last week.
I've got about 20k in solar hardware on site currently. Had to go to Pueblo today to pick up approx 2000' of wire for this project. WIre was shipped LTL, but I've had dealings with the trucking firm in Pueblo, so to minimize the aggravation, I just did a 150 mile round trip and picked it up at the terminal. With all the complications that have happened, I'm about 2 months behind where I wanted to be. Even though it is pretty hot right now, we have had snow in September in previous years. I sure as heck want to get all the outside work done by mid September.
Months ago I was doubting my sanity in doing this project. I do believe that I am now certified crazy. Maybe more beer will fix things.
Oh, and on the question I thought I had, driving back from Pueblo today I think I figured out way of getting the big EMT fittings connected to the EMT in the wall.
Lowell
Attachments
![DSCF7326[1].JPG](/data/attachments/164/164086-0b9c671976181504a49ae3dafa046bc8.jpg)
![DSCF7325[1].JPG](/data/attachments/164/164087-d42b9e49ad912edf01616e28606eb3b4.jpg)
Had a minor milestone yesterday. Rack is now put together with 24 panels hung. Wife said that this is the last big project - so looks like I'm done during this lifetime.
I've been putting off sourcing the last of the electrical equipment because of a couple nagging questions that I haven't been able to answer.
I'm using a Sol-Ark 15k and am required to have a manual AC disconnect between it and the utility. And by choice I'm also installing a transfer switch so that I can switch from the Sol-Ark to the Grid if needed. To be compliant with NEC 2020, do these need to be 3 pole units, i.e. does the neutral need to be disconnected?
Thanks for any replies,
Lowell
I've been putting off sourcing the last of the electrical equipment because of a couple nagging questions that I haven't been able to answer.
I'm using a Sol-Ark 15k and am required to have a manual AC disconnect between it and the utility. And by choice I'm also installing a transfer switch so that I can switch from the Sol-Ark to the Grid if needed. To be compliant with NEC 2020, do these need to be 3 pole units, i.e. does the neutral need to be disconnected?
Thanks for any replies,
Lowell
Attachments
![DSCF7345[1].JPG](/data/attachments/165/165420-964f96575f5c06c66c4e9799414ef2a8.jpg)
Hedges
I See Electromagnetic Fields!
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- Mar 28, 2020
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- 20,912
I'm not aware of any need to transfer neutral for a fixed system. Just mobile, where you disconnect from shore power that provided neutral/ground bond.
But system might end up having loops, parallel paths for neutral and ground. Is that actually a bad thing? Mine happen to be a "Y" route branching to/from inverter, rather than than going through it and continuing in another conduit, so I don't have that issue.
I think you need OCP as well as disconnect on input to SolArk.
What I've done with my SMA is have a 200A breaker panel downstream, with generator interlock between 200A grid input and 125A input from inverters. Costs about $50 for interlock and $50 for circuit breaker. In addition, fused disconnect from grid to inverter input.
But system might end up having loops, parallel paths for neutral and ground. Is that actually a bad thing? Mine happen to be a "Y" route branching to/from inverter, rather than than going through it and continuing in another conduit, so I don't have that issue.
I think you need OCP as well as disconnect on input to SolArk.
What I've done with my SMA is have a 200A breaker panel downstream, with generator interlock between 200A grid input and 125A input from inverters. Costs about $50 for interlock and $50 for circuit breaker. In addition, fused disconnect from grid to inverter input.
I think I'm covered with what I described? The PoCo requires a disconnect between the I/O of the generation source (SolArk) and the grid. I'm putting in a 200 amp 240 volt manual two pole disconnect. NEC also says that I must have a way of disconnecting the generation source from the house. So my plan there was to use a 200 amp 240 volt 2 pole transfer switch with a lockable off position. The SolArk has internal breakers (200 amp) which I think satisfies the OCP requirement. Am I not on the same page? NEC 750.20 talks about requiring a disconnect for all conductors. I didn't know if that means the neutral also. I sure as heck don't want to buy $1500 worth of boxes with two poles when I really need three poles. The utility pedestal has a 200 amp breakered disconnect.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
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SolArk has 200A breaker on inverter output only. Inverter input (from grid) is just lugs, no OCP.
If your 200 amp 240 volt disconnect is fused, you're good. If not, need fuse or breaker. Most of the Square-D switches are available fused and unfused, NEMA-1 and NEMA-3R
Perfect, that takes care of OCP. Something like Polaris downstream of that can go to non-fused visible blade disconnect, maybe either 200A main or 125A backfed "generator" breaker of a panel (if you use interlock for bypass), more taps for future expansion.
Of course, if you get a 200A transfer switch that can feed 200A from either grid or SolArk into loads panel. But I think you would need another 200A knife switch for the required disconnect between generator (SolArk) and grid. Draw a block diagram and make sure you've got the required and desired functionality.
I'm thinking DPDT unfused knive switch for disconnect, 200A & 125A interlocked breakers for bypass. If inverter doesn't get repaired and returned fast enough you can swap wires for 200A direct from grid.
I'm not finding the particular words in "NEC 750.20" so not sure about that.
Could be that N-G bond is supposed to occur at first disconnect after meter for that path, and first disconnect after inverter for that path? I don't always care as much about rules as things making sense and working. SolArk, if designed to mobile requirements, would switch neutral and bond internally. But I don't think it does. I would prefer neutral continuit and bond always being present, whether SolArk is present or removed. For my lower pass-through amperage, I accomplished that with a single conduit carrying input and output wires for inverter.
Oh, and I don't believe loops in ground, or in neutral, are a bad thing. Which means routing ground and neutral with both input and output works, together with routing them to load panel both direct from grid and from inverter.
If your 200 amp 240 volt disconnect is fused, you're good. If not, need fuse or breaker. Most of the Square-D switches are available fused and unfused, NEMA-1 and NEMA-3R
Perfect, that takes care of OCP. Something like Polaris downstream of that can go to non-fused visible blade disconnect, maybe either 200A main or 125A backfed "generator" breaker of a panel (if you use interlock for bypass), more taps for future expansion.
Of course, if you get a 200A transfer switch that can feed 200A from either grid or SolArk into loads panel. But I think you would need another 200A knife switch for the required disconnect between generator (SolArk) and grid. Draw a block diagram and make sure you've got the required and desired functionality.
I'm thinking DPDT unfused knive switch for disconnect, 200A & 125A interlocked breakers for bypass. If inverter doesn't get repaired and returned fast enough you can swap wires for 200A direct from grid.
I'm not finding the particular words in "NEC 750.20" so not sure about that.
Could be that N-G bond is supposed to occur at first disconnect after meter for that path, and first disconnect after inverter for that path? I don't always care as much about rules as things making sense and working. SolArk, if designed to mobile requirements, would switch neutral and bond internally. But I don't think it does. I would prefer neutral continuit and bond always being present, whether SolArk is present or removed. For my lower pass-through amperage, I accomplished that with a single conduit carrying input and output wires for inverter.
Oh, and I don't believe loops in ground, or in neutral, are a bad thing. Which means routing ground and neutral with both input and output works, together with routing them to load panel both direct from grid and from inverter.
Well, am now scratching my head, trying to figure out the ground neutral thing.
Most of the gut busting work is done. Inside and outside gutters are installed, interconnected with 2.5" EMT. I've got conduit paths completed from the utility supply to the gutter and gutter to the main panel. Transfer switch is mounted to the outside wall with a 2.5" EMT between it and the outside gutter. Ready to run wire, but have gotten confused. Should be simple, but I'm hung up on the neutral/ground stuff.
I've got 4 wires coming in from the service pedestal; two hots, neutral and a ground. The main panel has the two hots and neutral connected at the usual place, the ground wire from the pedestal is connected to a ground bus in the main panel and then a 4 awg bare copper is run from the ground bus to the ufer.
I believe my transfer switch is now where the neutral/ground bonding should take place. Would I run the service neutral, service ground and the 4 awg bare copper service ground to the neutral bus on the transfer switch? Then disconnect the neutral/ground bond at the main service panel? For some reason this doesn't make sense to me. I have to study the main service panel to see if I can unbond in there.
Most of the gut busting work is done. Inside and outside gutters are installed, interconnected with 2.5" EMT. I've got conduit paths completed from the utility supply to the gutter and gutter to the main panel. Transfer switch is mounted to the outside wall with a 2.5" EMT between it and the outside gutter. Ready to run wire, but have gotten confused. Should be simple, but I'm hung up on the neutral/ground stuff.
I've got 4 wires coming in from the service pedestal; two hots, neutral and a ground. The main panel has the two hots and neutral connected at the usual place, the ground wire from the pedestal is connected to a ground bus in the main panel and then a 4 awg bare copper is run from the ground bus to the ufer.
I believe my transfer switch is now where the neutral/ground bonding should take place. Would I run the service neutral, service ground and the 4 awg bare copper service ground to the neutral bus on the transfer switch? Then disconnect the neutral/ground bond at the main service panel? For some reason this doesn't make sense to me. I have to study the main service panel to see if I can unbond in there.
Hedges
I See Electromagnetic Fields!
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For mobile applications, neutral-ground bond is supposed to come from shore power pedestal.
When inverter disconnects from grid, it disconnects neutral as well as line(s). And, it bonds neutral to ground inverter.
If yours is not mobile and you will always be connected to grid wires, can rely on its neutral-ground bond, then you pass neutral through and don't bond locally. That is what I've done with Sunny Islands hanging on the wall.
When inverter disconnects from grid, it disconnects neutral as well as line(s). And, it bonds neutral to ground inverter.
If yours is not mobile and you will always be connected to grid wires, can rely on its neutral-ground bond, then you pass neutral through and don't bond locally. That is what I've done with Sunny Islands hanging on the wall.
Back when I was doing iterations on my PV package submittal to the State, the inspector mentioned that the transfer switch would be considered the first disconnect.
When the electricians brought the service into the house in 2015, they installed a 4 awg bare copper wire from the main panel's ground bus to the ufer. The ground wire from the service pedestal was also connected to the same ground bus in the main panel.
The service pedestal is about 30 feet from the house main breaker panel. I believe I had read somewhere that a ground/neutral bond was required at the house in case the ground connection fails at the service pedestal or transformer.
Getting brain locked on this.
When the electricians brought the service into the house in 2015, they installed a 4 awg bare copper wire from the main panel's ground bus to the ufer. The ground wire from the service pedestal was also connected to the same ground bus in the main panel.
The service pedestal is about 30 feet from the house main breaker panel. I believe I had read somewhere that a ground/neutral bond was required at the house in case the ground connection fails at the service pedestal or transformer.
Getting brain locked on this.
Most important thing is to have only one neutral ground bond.
From your single line drawing, you show the breaker before the meter which seems odd , but may be local practice. Do you have access to the lower compartment of the meter box, where that disconnect is, to confirm how it's wired?
From your single line drawing, you show the breaker before the meter which seems odd , but may be local practice. Do you have access to the lower compartment of the meter box, where that disconnect is, to confirm how it's wired?
I should be able to take the pedestal apart, but I think I have solved the puzzle. Went to a neighbor's house that was just recently built to take a look at his panel. He also has a backup generator. My main panel is wired the same as his is. Back at my place I killed the power at the pedestal and disconnected the ground wire coming from the pedestal. My ohm meter says that there is continuity between the service ground and the neutral. So I think the neutral/ground bond must be at the pedestal. On a second thought, I'm gonna kill power again and disconnect both the service ground and service neutral to make sure the meter was not seeing a ground path by another route.
Yep, disconnected the neutral and the ground coming from the service pedestal to the main panel - 0 ohms between them. So the neutral/ground bonding has to be done at the pedestal.
I was planning on running a neutral out to the transfer switch, but now wonder if that is just a waste of wire?
I was planning on running a neutral out to the transfer switch, but now wonder if that is just a waste of wire?
zanydroid
Solar Wizard
Wouldn’t there be imbalanced current along that section of the circuit in the absence of a neutral?
EDIT: see below discussion. Carrying the neutral does not appear to be required but you need to take care of extra aspects of the installation to be code compliant.
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Yeah I made error, those neutrals will have to come over to the transfer switch and just be joined.
On an electrical forum, one of the guys pointed out that the neutral only needs to be run to where it is used. I'd have to go back through a forum thread to find the NEC reference he quoted. In my case the neutral is being used in two places; the main breaker panel and the Sol-Ark inverter. I had checked with one of the inspectors and he agreed that I only need a two pole transfer switch (I don't need to switch the neutral). So I think the neutral is not used at the transfer switch. I think in one of @Hedges replies he mentioned that he had several neutral branches on his setup.
The Sol-Ark has two AC paths. One is bidirectional with the grid, while the second one is a unidirectional feed to the main breaker panel. In my interior wire gutter I will have the service neutral connected to a Polaris splice with a wire going to the breaker panel and another wire going to the neutral bar on the Sol-Ark. So each load will see two hots (L1 and L2) along with a neutral connection. I really don't see any reason for a neutral to run back and forth from the xfer switch. Likewise the grid connection to the Sol-Ark has to have a production meter and an AC disconnect. I see no reason to run a neutral along that path, because the neutral is not used by either of those pieces of hardware. ????
The Sol-Ark has two AC paths. One is bidirectional with the grid, while the second one is a unidirectional feed to the main breaker panel. In my interior wire gutter I will have the service neutral connected to a Polaris splice with a wire going to the breaker panel and another wire going to the neutral bar on the Sol-Ark. So each load will see two hots (L1 and L2) along with a neutral connection. I really don't see any reason for a neutral to run back and forth from the xfer switch. Likewise the grid connection to the Sol-Ark has to have a production meter and an AC disconnect. I see no reason to run a neutral along that path, because the neutral is not used by either of those pieces of hardware. ????
zanydroid
Solar Wizard
I would love to see that code reference. It’s a tricky subject.
The electricity will function in the sense that everything will turn on. However that is not the only requirement.
Not using neutral in the transfer switch is a different issue from running the neutral along with the L1/L2 — running all current carrying conductors together achieves the maximum cancellation of electromagnetic fields generated by the flowing AC current.
Since you do not ever have instantaneously balanced 120 legs you will not have balanced current between L1/L2.
Outside context problem.
The electricity will function in the sense that everything will turn on. However that is not the only requirement.
Not using neutral in the transfer switch is a different issue from running the neutral along with the L1/L2 — running all current carrying conductors together achieves the maximum cancellation of electromagnetic fields generated by the flowing AC current.
Since you do not ever have instantaneously balanced 120 legs you will not have balanced current between L1/L2.
I doubt any of the paths are electrically unidirectional. I guess in your situation you don’t have any other power sources so it effectively is unidirectional.
I was thinking 300.3 (B) Conductors of the Same Circuit might apply but after further research I don't think this applies in your case, and you will be OK not running a neutral thru your transfer switch.
In the electrical forum I was pointed to 300.3(B) and 300.20(A) as the primary references.
I finally located an electrician who is willing to come out and provide some advice. But he may talk about a completely different way of doing things. I'm starting to get close to conduit fill limitations even though I'm using 2.5" EMT. I need to cogitate on this some more.
What I keep getting hung up on is that I've got two AC paths to the end user load (main breaker panel). For one path, the grid goes through the xfer switch and then to the breaker panel. The other path has the grid going to the Sol-Ark whose load output goes to the xfer switch and then to the breaker panel. Both L1/L2 paths use the same neutral. So if I do have to have a neutral run to the transfer switch - would the neutral from the service run to the xfer switch, then to the neutral bus bar on the Sol-Ark, then there would be a neutral wire going from the Sol-Ark neutral bus bar to the breaker panel? The path going to the Sol-Ark also has an AC disconnect and a production meter neither of which uses the neutral. If I end up having to run a neutral out and back through those I might be in trouble with conduit fill.
I vaguely understand the concept of inductance loads and induced currents, but for the short distances I'm dealing with here, I can't see that it would be a significant factor. But the Code is the Code.
Thanks for providing input @Hedges, @zanydroid and @pvgirl.
