Module wiring safety [RE-wrenches]

[Matt Tritt]

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This is all getting so interesting.

A number of years ago I suggested to a module manufacturer that they 
switch from a metallic frame to pultruded fiberglass and, while they 
were at it, instead of supplying a pair of leads to connect to - create 
a waterproof  polarized plug on the ends of each module that would allow 
joining the modules in series and, at each series end, allow a plug-in 
home run (to a combiner). This would eliminate the need for grounding 
frames and interconnect wires (and be nice and clean).

They graciously declined to spend a bunch of money on R&D' ing something 
so unusual. But I still think it has some merit.

Matt T

William Miller wrote:

>
> Sky:
>
> I think your are taking this a bit further than is intended.  No one 
> is saying that touching the outside of an insulated wire is going to 
> kill anyone.  Let me try to explain it one more time:
>
> What we are saying is that unprotected wire, when subject to abuse 
> that will, given time, very likely happen, can expose energized metal 
> parts and pose a serious safety hazard.
>
> Here is just one scenario:  The similarity between a Unirac ULA ground 
> mount and a child's play structure is self evident.  That children 
> will want to climb on this type of structure is inevitable.  That 
> children will accidentally grasp one of the leads such as pictured on 
> my rogue's gallery is also inevitable.  Will the weight of a 40 pound 
> child swinging on one if these wires stretched across a metal edge 
> pierce the insulation?  It seems very likely to me.  Will the pin or 
> socket pull out of the plastic connector shell?  This also seems 
> highly likely.
>
> There is consensus on the above logic in the electrical industry at 
> large.  This is why you must protect any high voltage wire (>30 volts) 
> with conduit if it is accessible to the public.  The only exception to 
> this I know of, as of now, are PV circuits.
>
> Your reference to a utility drop is a non-sequitur:  The utility drop 
> is 10 feet in the air.  Your reference to lamp cords does not apply 
> either for the reason Michael Welch cited:  these are cord connected 
> devices-- when kids tug on them, they pull out of the receptacle.
>
> There has developed a temporary precedent in the PV industry that is 
> allowing unconduited high voltage leads.  My  theory is that the 
> regulating industry has been slow to react to the fact that PV systems 
> are no longer limited to 12 volts, 24 volts or even 48 volts nominal.  
> They now push the 600 volt ceiling.  The new code requirements are 
> written by those who are experienced in fire and electrical safety 
> responding to new high voltage string technology.
>
> I really hate to propose something that might affect anyone's bottom 
> line, but the pursuit of quick profit over long term public safety 
> does not cut it, in my value system.
>
> I guess we will have to agree to disagree, and I see no reason for you 
> and I to discuss this any further.  The science is conclusive 
> however-- 400 VDC at 5 amps is lethal.  I can't figure how you 
> rationalize out of that fact.
>
> Respectfully,
>
> William Miller
>
>
>
>
> At 02:59 PM 1/23/2008, you wrote:
>
>> William,
>>
>> Your logic is flawed.
>>
>> The answer to 1 and 2 is clearly yes.
>>
>> If the answer to 1 was no then we would all be dead by now. And the
>> utilities would run our power lines in conduit.
>>
>> If the answer to 2 was no then we would not be allowed to use extension
>> cords or plug in appliances in this country.
>>
>> I appreciate your desire to improve safety. But taking it too far will
>> result in many more deaths than saves.
>>
>> Saying that the liquid tight or the Volt guard makes the ground mount
>> safer is simply not true. They trade one set of extremely unlikely
>> hazards for another set. I like the look of the volt guard and will
>> offer it as an option to customers. Some people will be happy to pay an
>> extra 1 to 2% for the look. But to simply require customers to purchase
>> it would make me feel like I was stealing. And if someone decided not to
>> purchase solar because it was to expensive due to an unnecessary option
>> that I tried to force I'd be as much a murdering eco criminal as those
>> who can afford clean energy but choose to pollute instead.
>>
>> Solar electricity is much safer than standard AC. Studies indicate the
>> human body can safely tolerate more DC than AC. Solar energy does not
>> generate GHG's, mercury or radioactive waste.
>
>
>
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