TED-5000 2 MTU Weirdness.

[DanS26]

I may be wrong, but I do not see either a fuse or CB protection for that #6 solar feeder wire. It appears to me that a short would draw the entire 200 amps from the main onto a #6 wire....this is a fire waiting to happen.

Edit....upon further review it may be even worse than a 200 amp draw..the # 6 solar wires are connected directly to the utility feed without protection. Time for a pro to take a closer look.

[SunEagle]

I may be wrong, but I do not see either a fuse or CB protection for that #6 solar feeder wire. It appears to me that a short would draw the entire 200 amps from the main onto a #6 wire....this is a fire waiting to happen.

Edit....upon further review it may be even worse than a 200 amp draw..the # 6 solar wires are connected directly to the utility feed without protection. Time for a pro to take a closer look.

That is my concern too. I am hoping that there are fuses inside that SQ D disconnect switch. They would protect the PV power wires connected in the transfer switch.

[DanS26]

That is my concern too. I am hoping that there are fuses inside that SQ D disconnect switch. They would protect the PV power wires connected in the transfer switch.

Just plain dangerous. Even if the the SQ D switch has fuses there is ~6' of undersized and unprotected wire. If no fuses in that switch or the outside switch then the entire system is extremely dangerous.

[SunEagle]

Just plain dangerous. Even if the the SQ D switch has fuses there is ~6' of undersized and unprotected wire. If no fuses in that switch or the outside switch then the entire system is extremely dangerous.

I can't tell what size wire is being used. The system diagram shows a 40A breaker so if there are 40A fuses in the SQ D switch and he is using #8 or larger wire then they are protected.

As you said. No fuses in the SQ D switch would be very dangerous since the next upstream "over current" protection is probably in the Inverter.

[DanS26]

I can't tell what size wire is being used. The system diagram shows a 40A breaker so if there are 40A fuses in the SQ D switch and he is using #8 or larger wire then they are protected.

As you said. No fuses in the SQ D switch would be very dangerous since the next upstream "over current" protection is probably in the Inverter.

The Fronius 7.5 requires a #6 wire from inverter to utility connection IF the installer is reading the manufacturers instructions. It is apparent that he is not following NEC codes.

[SunEagle]

The Fronius 7.5 requires a #6 wire from inverter to utility connection IF the installer is reading the manufacturers instructions. It is apparent that he is not following NEC codes.

I must have missed the Fronius 7.5 model somewhere.

I was going by the electrical drawing in post #16 that shows the wiring between the SQ D switch at #8 wire. It is tagged by the letter C which indicates 3 #8 wire.

[DanS26]

I must have missed the Fronius 7.5 model somewhere.

I was going by the electrical drawing in post #16 that shows the wiring between the SQ D switch at #8 wire. It is tagged by the letter C which indicates 3 #8 wire.

See post #1, first sentence second paragraph....."MTU2 is for a 7500KW solar system". The inverter pics appear to be a Fronius IG Plus V 7.5.

Time for the installer to answer some questions and if this installation is non-compliant to make the necessary corrections.

Makes you wonder where the inspector was in this installation.

[SunEagle]

See post #1, first sentence second paragraph....."MTU2 is for a 7500KW solar system". The inverter pics appear to be a Fronius IG Plus V 7.5.

Time for the installer to answer some questions and if this installation is non-compliant to make the necessary corrections.

Makes you wonder where the inspector was in this installation.

Yep. I see the reference now.

It is possible the wires are #6 with the appropriate fusing in the SQ D switch but I am just guessing at this point.

[DanS26]

Yep. I see the reference now.

It is possible the wires are #6 with the appropriate fusing in the SQ D switch but I am just guessing at this point.

Fuses at the switch would help but still would not make the installation compliant with NEC rules.

[SunEagle]

Fuses at the switch would help but still would not make the installation compliant with NEC rules.

I have to go back and research a little more but maybe the 1/3 amp 10ft tap rule fits. (200amp panel with 6 feet of #6 wire rated ~65amps being terminated at the switch with 60amp fuses).

[inetdog]

I have to go back and research a little more but maybe the 1/3 amp 10ft tap rule fits. (200amp panel with 6 feet of #6 wire rated ~65amps being terminated at the switch with 60amp fuses).

The application of any tap rule is a little clouded in the PV inverter output circuit case, since the wire gets power from both ends, although only substantial short circuit current from the POCO facing end.
It is not clear to me that the rules for sizing inverter output wiring, which are not in Chapter 2, are subject to overriding by the tap rules in that chapter.

[SunEagle]

The application of any tap rule is a little clouded in the PV inverter output circuit case, since the wire gets power from both ends, although only substantial short circuit current from the POCO facing end.
It is not clear to me that the rules for sizing inverter output wiring, which are not in Chapter 2, are subject to overriding by the tap rules in that chapter.

Yeah it is still fuzzy to me. I was hoping for someone very familiar with the NEC PV code would chime in. I certainly would have put a breaker or fuses before connecting those pv wires to the transfer switch.

[RiggedCT]

Yeah it is still fuzzy to me. I was hoping for someone very familiar with the NEC PV code would chime in. I certainly would have put a breaker or fuses before connecting those pv wires to the transfer switch.

Like I said on the TED-5000 forum.

But this installation passed 3 separate inspections. One from the RGS solar electrical Engineer, One from the local Town Inspector, and one From United Illumination

Is it possible that all 3 got it wrong? I am not being sarcastic. I am truly asking. What more information do you guys need? Another picture with more detail? Let me know.

[RiggedCT]

Ok. Here is what I think from postings here and other places. Mind you I am far from qualified. Feel free to tell me I am an idiot.

GREEN = The Power coming from the Panels.

LIGHT BLUE Outside Disconnect for Utilities Provider

YELLOW AC Path (Generated Power)

RED Disconnect before tie in. Would there not be fuses in here? That seems logical to someone who has no clue. I will Check on it Saturday night when I get home and take a picture.

[DanS26]

Like I said on the TED-5000 forum.



Is it possible that all 3 got it wrong? I am not being sarcastic. I am truly asking. What more information do you guys need? Another picture with more detail? Let me know.

Simple, just open up the Square D switches....if you see fuses you're OK.