Ok. The neutral is not the GEC. Got it.The GEC is NOT the neutral. It's it's own thing.
Although it (the GEC) may share that function with the EGC, definitely not the neutral.The GEC is NOT the neutral. It's it's own thing.
It is grounded by being connected to the feeder neutral, which in turn is connected to the service neutral, which in turn is grounded.There's still a neutral coming from the inverter which has to be bonded somewhere.
In the second diagram yes. 690.47(C)(3) in the 2011 code allows one to combine the functions of the EGC and GEC into one conductor for a solar inverter. This is the only place in the code that allows such a combination, AFAIK. A new section was added to the code in 2011 explicitly prohibiting it in general.If the inverter neutral in this diagram doesn't count as the ground conductor, the EGC of the inverter must be the GEC then?
It's at the main service. There is a wire shown connecting the neutral and ground bars. That's the main bonding jumper.It's that "one point" on the customer side that's bugging me. I can't quite figure out where it is, it doesn't seem to be where GoldD is saying it should be.
I get why there are two 200A busses.Although it (the GEC) may share that function with the EGC, definitely not the neutral.
That is just the way panels and devices are labelled. A 200A 120/240 panel will have two 200A buses. A 208Y/120 three phase panel will have three 200A buses. A two phase five wire panel (if they existed) would have four 200A buses.
You do not get to change the industry standard naming convention based or your sense of how it should be.
A 200A breaker, regardless of how many poles it has, will limit each pole to 200A.
Say it's noon and the PV is at max output (32 amps).
The loads drawn from the secondary panel are cooking along at 50 amps of 240V (which is the same as 100 amps of 120V loads. The load is 12kVA)
That means there's 32A from PV and 18A from the grid supplying the sec. panel loads. Fine.
Someone decides to to bit of welding or something in addition.
A 60 amp welder.
That puts the secondary panel loads at 110A > than the 100A main breaker, less than the bus rating.
What happens then?
Another 50A coming from the grid (for a total of 68A coming from the grid) isn't going to trip the 100A breaker. Won't that cause bus issues?
Or...if it is going to trip the 100A breaker, what about all the other breakers (PV and loads) remaining closed on the load side of the tripped breaker? Won't 36A of PV output still be going to 110A of loads?
Seems like of course the PV breaker would also trip.
I'm wondering about when GoldD said-
"There is no cross section of the bus carrying more than 100A."
It does seem like the PV breaker would trip too, but even if it does, the N and G from the inverter are still connected, all the way to the main panel, and possibly the LV side service ground.
With all the load equipment breakers still closed.
So the "terminations" don't count as "points" then, towards the "only one point"?jaggedben
It is grounded by being connected to the feeder neutral, which in turn is connected to the service neutral, which in turn is grounded.
1 jben said that yes, the EGC from the inverter is its' GEC- so isn't it connected to more than one point?1 If the inverter output goes to a subpanel, then the neutral goes to the neutral bar there and the EGC goes to the EGC bar. From those two bars separate feeder wires go back to the main panel.
2 And a 200A 120/240 single phase 3 wire service can supply 400A worth of 120V loads if they are balanced and there are no 240V loads.
Thanks.If you start with more than about 90A 240V load before the welder, when it adds in 40A neither PV backfeed breaker nor feeder breaker will not *necessarily* trip, depending on how the current divides. If the PV produces more than 30A the feeder will not trip since it is supplying 130 - 30 or less. The PV breaker cannot trip first since it cannot have more than 32 A flowing. If the feeder breaker happens to trip the PV breaker still cannot trip, but the GTI will shut down.
If you turn off the PV or a cloud goes by then the feeder will probably trip.
Remember 32A of PV plus 40A of welder load makes 8A of load, not 72. I think this may be part of your problem.
They don't count. The 'one point' is where that neutral conductor is connected to ground, (i.e. the dirt of the earth) via a main bonding jumper that in turn connects it to the grounding electrode conductor and electrode.me-
So the "terminations" don't count as "points" then, towards the "only one point"?
Just to note...Thanks.
I'm saying there's 50A of 240V load at noon, at the same time the PV output = 32A max.
Then the 60A of welder kicks in, putting the total load at 110A.
So the 100A breaker won't trip because there's only 78A coming from grid, the other 32 is going straight to loads from PV.
But the 120% rule is there whether there are any loads in the panel at all.Just to note...
If you have that much potential load on the feeder then you had probably better upsize the 100A feeder and breaker anyway, because you can't count on the sun shining when you want to use that power.
This is one reason the 120% is a little bit silly, as it would take someone very nimble and knowledgeable to consistently use loads that high without suffering nuisance tripping.
Sometimes the box is there for a reason, like because of physics, NEC regulations, equipment capabilities, etc. The only time "outside the box" thinking is valid is when you understand what the box is and why it's there, otherwise it's just speculation from a position of ignorance.1 It's gotta be either my outside of the box thinking...
No. A 200A breaker is 200A, period. 200A at 240V, 200A at 120V... just 200A. You do not add phase amps to get line amps.JAZ's main breaker for the sec. panel is 100A...that's 100A at 120V, correct?
His main breaker in the main panel is 200A- that means 200A of 120V and 100A of 240V.
They don't count. The 'one point' is where that neutral conductor is connected to ground, (i.e. the dirt of the earth) via a main bonding jumper that in turn connects it to the grounding electrode conductor and electrode.
You know, our host Mike Holt has published a lot of resources that might help clear up a lot of this for you. Lots of nice illustrations. Try some of his Youtube vids.
Um...thanks!PS: I do think that you are salvageable, it is just taking a long time.
Dude...I was trying to make a joke at my own expense referencing zman's "out of the box" thinking- and saying it may not always be a good thing.otherwise it's just speculation from a position of ignorance.
So does that mean it will be even "sillier" if they raise 120% to 150%, as I've seen talk of doing?This is one reason the 120% is a little bit silly, as it would take someone very nimble and knowledgeable to consistently use loads that high without suffering nuisance tripping.
No, it would be less silly. Basically, what people have said is that since the solar is there intermittently, any load that was over the busbar rating would probably trip the utility feed breaker at some moment when the sun was not shining. In other words, people can't count on using that much load, so really a 200% rule might not be silly, and the 120% rule is very, very conservative, at least when the source is solar. 150% seems like a good compromise n my opinion, for solar and wind, but I don't work for UL.So does that mean it will be even "sillier" if they raise 120% to 150%, as I've seen talk of doing?
Who knows want they want exactly and why. Probably the guy asking for it isn't familiar with the code requirements for a GEC or else he wouldn't be asking for it. It's a good guess that giving them an unspliced/irreversibly spliced green wire back to the electrode (UFER) at the service will satisfy their request. Such a wire would still be connected to the subpanel ground bar and all the other grounded parts, but the idea is that would not be possible to remove the connection between inverter and service at any point in between without cutting the wire.This diagram seems a lot simpler today- JAZ's POCO doesn't want the green/G line coming from the inverter attached to the ground bar in the sub panel.
They want it to run from the inverter to the main panel ground bar unspliced/no connections.
So it's bonded at the one point, same point as the inverter N.