Module leads (USE-2) need to be in conduit

[weressl]

You're not that far from me, you know.

Austin? It's a world away.....

 

[iwire]

As mentioned already, micro-inverter systems.

This is becoming silly.

There is no other line voltage equipment that the NEC allows to be wired 'free air' with single conductors, they gave us a break with inaccessible PV arrays, once they become accessible that allowance goes away ...... as it should in my opinion or they should start letting me wire other equipment free air single conductors.

 

[jaggedben]

This is becoming silly.

There is no other line voltage equipment that the NEC allows to be wired 'free air' with single conductors, they gave us a break with inaccessible PV arrays, once they become accessible that allowance goes away ...... as it should in my opinion or they should start letting me wire other equipment free air single conductors.

Where are the "line voltage free-in-air single conductors" on a micro inverter system? The single conductors are max voltage 45V or so (usually far less, and operating voltages are usually under 30). The line voltage conductors are not single conductors.

 

[weressl]

Where are the "line voltage free-in-air single conductors" on a micro inverter system? The single conductors are max voltage 45V or so (usually far less, and operating voltages are usually under 30). The line voltage conductors are not single conductors.

If you have several, say 4, cells connected in series and a wire is broken, can you tell me what the potential difference will be between the two ends?

 

[ggunn]

If you have several, say 4, cells connected in series and a wire is broken, can you tell me what the potential difference will be between the two ends?

Maybe I don't understand your question. In a microinverter system there is a separate inverter for each module and the inverter outputs are connected in parallel. Nothing is in series external to the module. The cells within the module are in series/parallel but there are no external conductors (wires) to break. Single module Voc's (open circuit voltages) are generally less than 45VDC.

 

[BillK-AZ]

If you have several, say 4, cells connected in series and a wire is broken, can you tell me what the potential difference will be between the two ends?

Depends on the system circuitry. If there are no other cells/modules in parallel, then the voltage across a break is the circuit open circuit voltage. If there are other parallel cells/modules then the voltage across a break is the circuit open circuit voltage less the operating voltage of the parallel cells/modules.

 

[weressl]

Depends on the system circuitry. If there are no other cells/modules in parallel, then the voltage across a break is the circuit open circuit voltage. If there are other parallel cells/modules then the voltage across a break is the circuit open circuit voltage less the operating voltage of the parallel cells/modules.

SERIES connection was the question on large centralized inverter systems where the DC voltage of the SERIES connected cells could be hundreds of volts.

 

[jaggedben]

SERIES connection was the question on large centralized inverter systems where the DC voltage of the SERIES connected cells could be hundreds of volts.

You're question appeared as a reply to me, and I specifically referenced micro-inverter systems, which don't have series connected modules. The max voltage from a single module is typically below 45V for 60 cell modules, below 50V for 72 cell modules, and below 55V for high efficiency modules. That's at extreme low temperature.

As for series connected modules, as Bill said, potential difference across a broken circuit depends on system design. It also depends on module type.

 

[weressl]

You're question appeared as a reply to me, and I specifically referenced micro-inverter systems, which don't have series connected modules. The max voltage from a single module is typically below 45V for 60 cell modules, below 50V for 72 cell modules, and below 55V for high efficiency modules. That's at extreme low temperature.

As for series connected modules, as Bill said, potential difference across a broken circuit depends on system design. It also depends on module type.

Your answer narrows down the variety of PV configurations to a single configuration which does not present a problem. OK, done, how about all the others?

 

[jaggedben]

OK, done, how about all the others?

What about them? (What's the question again?) :roll:

 

[weressl]

What about them? (What's the question again?) :roll:

That is what they call in debating terms: intellectual dishonesty.:dunce:

 

[jaggedben]

That is what they call in debating terms: intellectual dishonesty.:dunce:

I'm tempted to respond in kind, but I'll restrain myself.

You asked a very open ended question about PV voltages in series strings. Good answers were already given: It depends on the system design and the panels used. If you have a more specific question you should ask it. And if you have a point about how this relates to the original subject of this thread, you should just come out with it.

 

[weressl]

You asked a very open ended question about PV voltages in series strings. Good answers were already given: It depends on the system design and the panels used. If you have a more specific question you should ask it. And if you have a point about how this relates to the original subject of this thread, you should just come out with it.

That is incorrect, I have asked a specific question and the answer relates to the OP question about the safety of exposed wires.

 

[jaggedben]

That is incorrect, I have asked a specific question and the answer relates to the OP question about the safety of exposed wires.

Bill already gave the answer in post #46.

 

[ggunn]

That is what they call in debating terms: intellectual dishonesty.:dunce:

What was your question, anyway? Something about exposed wires connecting cells, wasn't it? PV cells are not connected by exposed wires, except maybe in experimental setups which are not expected to be code compliant, like solar powered project cars.

 

[weressl]

Bill already gave the answer in post #46.

The question gave a sample value, the answer was a general statement, not addressing the value in the question, therefore it was not 'the answer'. If you are asked in a quiz what is 2+2 and you answer 'a number', would that be an acceptable answer? (Incidentally, do you realize that post #46 is a meaningless reference when somebody else uses a different display mode than you, ex. linear versus hybrid?)

 

[ggunn]

The question gave a sample value, the answer was a general statement, not addressing the value in the question, therefore it was not 'the answer'. If you are asked in a quiz what is 2+2 and you answer 'a number', would that be an acceptable answer?

Your question was more like "what is a number plus a number?" "A number" is an acceptable answer, IMO.

 

[weressl]

What was your question, anyway? Something about exposed wires connecting cells, wasn't it? PV cells are not connected by exposed wires, except maybe in experimental setups which are not expected to be code compliant, like solar powered project cars.

The whole post is about PV wires run exposed, not in conduit as there is no threaded opening on the cells. There are centralized, large PV plants where individual cells are connected in series up to and even over 600V. Any break in the wire will produce a potential difference between the two broken ends the summ of open cell voltages.

 

[ggunn]

The whole post is about PV wires run exposed, not in conduit as there is no threaded opening on the cells. There are centralized, large PV plants where individual cells are connected in series up to and even over 600V. Any break in the wire will produce a potential difference between the two broken ends the summ of open cell voltages.

Do you know what a PV cell is?

 

[weressl]

Do you know what a PV cell is?

Will PV panel reference suit you better?