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

[iwire]

One code problem with junction boxes on modules is that you must use metal conduit due to temperatures over 75?C. Most PV modules with junction boxes do not have a deep enough box such that a straight conduit will clear the frame, requiring labor intensive offsets. Then there is the problem of supporting the conduit between modules. If the circuit is over 250 volts, the conduit must be bonded, another cost element. Deep junction boxes do not allow the close stacking on modules for shipping that is now common, adding to the cost of shipping.

Ahh ... the 'it's difficult and / or costly to do it right' reason.

 

[weressl]

Lots of reasons:

Because 99% of the modules will be used in situations where the plugs are a better answer. The only failures I have seen in PV wiring at the module level have been in junction boxes due to loose connections or water entry.

Plugs are a better answer for a permanently mounted apparatus? Outdoors?

One code problem with junction boxes on modules is that you must use metal conduit due to temperatures over 75?C. Most PV modules with junction boxes do not have a deep enough box such that a straight conduit will clear the frame, requiring labor intensive offsets. Then there is the problem of supporting the conduit between modules. If the circuit is over 250 volts, the conduit must be bonded, another cost element. Deep junction boxes do not allow the close stacking on modules for shipping that is now common, adding to the cost of shipping.

Just where would the 75?C come from? Is conduit the only NEC solution? I specifically not listed WHAT acceptable wiring method should be used. Shouldn't PV cells be grounded? Objections raised for the convenience of PV manufacturers are over-ridden by the need for equipment to be suitable for NEC compliant and safe installation.

 

[weressl]

Ahh ... the 'it's difficult and / or costly to do it right' reason.

The PV manufacturers do not care how costly the installation of their product will be. They are more concerned about meeting installation requirements in countries where CE rules and not NEC. Let's face it in the US you can get away with a lot more than other, comparable industrial countries. What I am implying here is the less-than draconian/governmental enforcement and variance of rules throughout the land.

On the next revision to the forum, let's consider the addition of a like AND a dis-like button. (Just to dispel any doubt, this post gets a LIKE.)

 

[weressl]

add'l idea: any chance the inspector would be satisfied with PV wire?
I am not sure it meets Code, but it is pretty robust. Double jacketed.
I checked out the link to the photo of wire managemnent under an array in Solar Pro. Thanks.

Is PV wire listed in the NEC?

 

[BillK-AZ]

Is PV wire listed in the NEC?

Starting with the 2011 revision: Art 690.31(B)

 

[ggunn]

Ahh ... the 'it's difficult and / or costly to do it right' reason.

Well, OK, but that calculation comes into play in every manufacturing situation. Nothing can be 100% safe and idiot-proof, and (for example) doubling the cost of something to eliminate a .001% chance of abuse or failure may not be worth the expense.

 

[weressl]

Well, OK, but that calculation comes into play in every manufacturing situation. Nothing can be 100% safe and idiot-proof, and (for example) doubling the cost of something to eliminate a .001% chance of abuse or failure may not be worth the expense.

That is NOT what we are talking about. It is not 0.001%, and nobody would argue if it was, but the assemblies supplied can-not be installed in an NEC compliant mode. The argument of fencing it in is NOT an electrical solution, so it is a cop-out argument.

Everybody in the trade should expect that a product can be installed, out of the box, in an efficient, cost-effective and safe way. The more over-seas product we see on our shores, the less likely that it is to be so. It mainly has to do with the toothless regulations and trade enforcment, not to mention ANSI is laying back on the electrical issues and let IEC to take over. Nice job, morons....:happysad:

 

[ggunn]

That is NOT what we are talking about. It is not 0.001%, and nobody would argue if it was, but the assemblies supplied can-not be installed in an NEC compliant mode. The argument of fencing it in is NOT an electrical solution, so it is a cop-out argument.

Everybody in the trade should expect that a product can be installed, out of the box, in an efficient, cost-effective and safe way. The more over-seas product we see on our shores, the less likely that it is to be so. It mainly has to do with the toothless regulations and trade enforcment, not to mention ANSI is laying back on the electrical issues and let IEC to take over. Nice job, morons....:happysad:

I never said that this was a 0.001% issue; it was only a "for instance"; economic tradeoffs with safety issues happen in every manufacturing product line.

If you can come up with a way to build modules cost effectively which completely encase all conductors in conduit while allowing the flexibility of installation methods that the present system of integrated conductors affords, then take it to market; you could be a very wealthy man. No offense intended, but it is easy to sit back and call people morons when it's not your responsibility and decision making on the line.

Meanwhile, we will continue to fence in our ground mounted PV systems when the AHJ tells us we have to.

 

[weressl]

I never said that this was a 0.001% issue; it was only a "for instance"; economic tradeoffs with safety issues happen in every manufacturing product line.

If you can come up with a way to build modules cost effectively which completely encase all conductors in conduit while allowing the flexibility of installation methods that the present system of integrated conductors affords, then take it to market; you could be a very wealthy man. No offense intended, but it is easy to sit back and call people morons when it's not your responsibility and decision making on the line.

Meanwhile, we will continue to fence in our ground mounted PV systems when the AHJ tells us we have to.

The 'morons' were aimed not at the producers, but at those who 'allows' them - by their inaction, to market such products. The producers will absolutely follow the market and produce what sells. What is missing from today's 'free market' is the ethics, where consumers are not treated as suckers.

 

[ggunn]

The 'morons' were aimed not at the producers, but at those who 'allows' them - by their inaction, to market such products. The producers will absolutely follow the market and produce what sells. What is missing from today's 'free market' is the ethics, where consumers are not treated as suckers.

Free market? There's no such thing.

 

[jaggedben]

It is not 0.001%, and nobody would argue if it was, ...

I think it may very well be a 0.001% issue. Which is to say, I think that for every 100,000 readily accesible PV strings installed, it may very well turn out that only 1 electrocutes someone because the conductors were not installed in a raceway. Just guessing, but the probability seems very low.

 

[iwire]

I think it may very well be a 0.001% issue. Which is to say, I think that for every 100,000 readily accesible PV strings installed, it may very well turn out that only 1 electrocutes someone because the conductors were not installed in a raceway. Just guessing, but the probability seems very low.

So in your mind having up to 600 volt single USE conductors exposed to the general public would be fine?

Sure would make a service easier to do, just run single conductors up the outside of a home. :happyno:

 

[Zee]

"The PV manufacturers do not care how costly the installation of their product will be."

Weressl,
Of course manufacturers care about the ease of installing their product! NOt all, but some.
1. ZEP groove equipped modules prove that.
2. Grounding holes and instructions for their approved use demonstrate that also.
3. And to the point, specifically the adoption of MC connectors (plugs) was possibly the greatest recent advance in module installation!

To boot: 1. and 3. are not regulated nor required.

 

[Zee]

Weressl,
A fence is not an elec. solution?

Fences work for the utility around power stations and towers. It most definitely IS a solution.

The only - possibly not compliant - systems are groundmounts under discussion here. ALL rooftop systems (say 90% are such) comply with NEC FULLY, single conductor cables, plugs, and all.

 

[weressl]

Free market? There's no such thing.

Not where you are, fher sure.....:lol:

 

[Zee]

Weressl,
I am not sure your negativity regarding
1. Regulators
2. Chinese products
3. Installers
4. Manufacturers
could be addressed with any technical answer.


I will continue to treat my customers ("suckers") ethically by giving them reliable, albeit less than perfect, 30 year - pollution free - systems.

 

[jaggedben]

So in your mind having up to 600 volt single USE conductors exposed to the general public would be fine?

No, that's not what I said. Someone mentioned 0.001% and I gave my opinion on that.

Then again, the NEC requirement isn't 600V. It's anything over 30. Seems a bit severe.

Sure would make a service easier to do, just run single conductors up the outside of a home. :happyno:

I don't think the available fault currents and arc flash hazards from service conductors are comparable to single PV strings.

 

[iwire]

No, that's not what I said. Someone mentioned 0.001% and I gave my opinion on that.

Then again, the NEC requirement isn't 600V. It's anything over 30. Seems a bit severe.

Then again how many arrays operate below a couple hundred volts?

I don't think the available fault currents and arc flash hazards from service conductors are comparable to single PV strings.

Of course, but the shock potential is the same.

Keep in mind I have run some PV projects and the company I work for has installed a great many large systems. So I do have a clue what the real issue is.

The issue is money, to do full conduit would mean raising the bid price and that will often put you out of contention.

 

[ggunn]

Not where you are, fher sure.....:lol:

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

 

[jaggedben]

Then again how many arrays operate below a couple hundred volts?

As mentioned already, micro-inverter systems.