Fusing solar panel cables

[WotEver]

Lol!!

[Graham.m]

As opposed to NIOSH which states "Under dry conditions, the resistance offered by the human body may be as high as 100,000 Ohms.

 

That sounds high. But I wonder if it was measure from toe to finger tip on someone 6 foot 7 ins in a very dry air conditioned lab in the middle of a desert. Highest my has been is about 5KOhms, frequently below if a bit sweaty.

[swift1894]

You have my support too Nick.

We have already lost Gibbo,so I would be unhappy to see someone as genuinely helpful as you stop using the forum..

Mine too? Edited December 12, 2015 by swift1894

[Graham.m]

 

That information states that there is 'no resistance' between two open wounds - which suggests to me that a 12V battery would deliver a fatal current. I haven't tried it though. Maybe we should use a few captured terrorists and try it out?

 

Interesting I can't find where it says "'no resistance' between two open wounds" searched for the words no can find.

 

Please can you tell me where on the words are?

 

Ah could these be the words you are refering to "Punctured skin with cuts, abrasions or burns caused by the electric current itself"

 

I think the important words there are "caused by the electric current itself" I think that is the effect of the power travelling through the flesh. I understand there is some form of reaction that reduce the resistance where the power has travelled.

 

It does not say well to me at least that the statement you made is correct i believe the statement is incorrect "That information states that there is 'no resistance' between two open wounds "

Edited December 12, 2015 by Graham.m

[swift1894]

What size fuse should be used between a Tracer MPPT 4215BN (40 amp rated system current) and the battery bank, 40 amp???

[Graham.m]

What size fuse should be used between a Tracer MPPT 4215BN (40 amp rated system current) and the battery bank, 40 amp???

 

I would suggest 125% of max current so 50A so long as the cable is capable of taking 50A

 

But you could reduce it if your panels are not capable of giving that amount of power

Edited December 12, 2015 by Graham.m

[Loafer]

 

Interesting I can't find where it says "'no resistance' between two open wounds" searched for the words no can find.

 

Please can you tell me where on the words are?

 

 

They aren't really words, as such, just the bottom line of this table, figures in red.

 

[Graham.m]

They aren't really words, as such, just the bottom line of this table, figures in red.

 

Screen Shot 2015-12-12 at 18.57.00.jpg

 

see #54

[Loafer]

 

see #54

 

I think it's only the BURNS caused by the current itself, not the cuts or abrasions. 'Punctured skin with cuts' is a separate issue.

[matty40s]

I'm finding it very tiresome too. Of course as soon as I get a bit grumpy with him he's straight off to Dan to complain, threatens to sue me for libel etc.

Anyway, I need support from someone so don't stop!

Sorry, I have given up...... he has come out with so much dross regarding solar.

I don't bother to read his posts anymore as I don't have much time to come on here so have to be selective in my reading.

Edited December 13, 2015 by matty40s

[Graham.m]

 

I think it's only the BURNS caused by the current itself, not the cuts or abrasions. 'Punctured skin with cuts' is a separate issue.

 

Suspect you have not seen the results of a major shock accident, cuts and abrasions happen during the shocking. Can be caused by even a wire.

[Loafer]

No I haven't seen anything like that. However, I did once HEAR that a 12V car battery COULD kill, if connected directly to TWO OPEN WOUNDS (one on each hand).

 

I didn't say it WOULD kill a person, I have no idea! I don't know what my internal resistance is, nor whether or not I have a weak heart.

 

I'm not talking about skin or flesh damage caused BY the incident - it was a purely theoretical musing from years ago, where it was possibly one of my university lecturers who mentioned it somewhere between 1974 and 1977.

 

I think that'll do for now, won't it?

[Graham.m]

No I haven't seen anything like that. However, I did once HEAR that a 12V car battery COULD kill, if connected directly to TWO OPEN WOUNDS (one on each hand).

 

I didn't say it WOULD kill a person, I have no idea! I don't know what my internal resistance is, nor whether or not I have a weak heart.

 

I'm not talking about skin or flesh damage caused BY the incident - it was a purely theoretical musing from years ago, where it was possibly one of my university lecturers who mentioned it somewhere between 1974 and 1977.

 

I think that'll do for now, won't it?

 

There are some people who get a shock from a 12 volt battery, it is due to their low body resistance. Sometime if you have a largish cut etc try measuring the resistance across the cut, do use sterilised probes, you might get a surprise as to how low it is.

 

Unfortunately, I have had to attend two inquests re death from shock, in both cases the skin had been damaged around the entry points and broken, abrasions and cuts.

 

It does not matter how the cuts or abrasions are caused once the skin is broken the body is very vulnerable to electricity entering at such a site.

 

People treat electricity with so little respect forgetting that it has the power to kill them at quite low currents.

 

Maybe this little exchange will make some to be that little bit careful

[Chewbacka]

Any thing more than my 24v system - solar at upto 70vDC and 240vAC I treat as very dangerous, and having read the above I have no intention of changing.

[Graham.m]

Any thing more than my 24v system - solar at upto 70vDC and 240vAC I treat as very dangerous, and having read the above I have no intention of changing.

 

If I may sugggest 50V DC not 70V DC is treated as highly dangerous. DC is worse than AC for shocks. The body convulses with DC and does not relax. With AC because the polarity is changing there is a goodish chance of being thrown off; rather than with DC the body holding on as the body has locked up.

[matty40s]

If I may sugggest 50V DC not 70V DC is treated as highly dangerous. DC is worse than AC for shocks. The body convulses with DC and does not relax. With AC because the polarity is changing there is a goodish chance of being thrown off; rather than with DC the body holding on as the body has locked up.

So you are now saying you can't even have two 24v panels in series.

Stop talking bollocks about solar.

Edited December 14, 2015 by matty40s

[Graham.m]

So you are now saying you can't even have two 24v panels in series.

Stop talking bollocks about solar.

 

Sorry where have I said that?

[Chewbacka]

Any thing more than my 24v system - solar at upto 70vDC and 240vAC I treat as very dangerous, and having read the above I have no intention of changing.

I will clarify my post as it was not clear.

 

Up to 24V which is my domestic system I do not avoid touching the terminals etc, but do take great care to avoid high current errors.

I consider my solar system in sunlight as hazardous as it runs at upto 70VDC and so I treat it in the same manner that I treat my 240V AC circuits. So I don't have exposed terminals, the cables are protected and clearly labelled etc. Also I will isolate the panels when working on the system.

That said, I am more than happy to have a 70v solar system on the boat, and If I had a third panel I would add it in series to give about 110v DC.

[swift1894]

Glad to have read all the warnings about high DC voltage. I have to admit I didn't realise the dangers.⚡️⚡️⚡️.

[Graham.m]

I will clarify my post as it was not clear.

 

Up to 24V which is my domestic system I do not avoid touching the terminals etc, but do take great care to avoid high current errors.

I consider my solar system in sunlight as hazardous as it runs at upto 70VDC and so I treat it in the same manner that I treat my 240V AC circuits. So I don't have exposed terminals, the cables are protected and clearly labelled etc. Also I will isolate the panels when working on the system.

That said, I am more than happy to have a 70v solar system on the boat, and If I had a third panel I would add it in series to give about 110v DC.

 

Chewbacka, how do you isolate the panels?

 

A 70V or 150V solar panels system, properly installed is no more dangerous than the 230V system on a boat that is properly installed.

[Chewbacka]

 

Chewbacka, how do you isolate the panels?

 

A 70V or 150V solar panels system, properly installed is no more dangerous than the 230V system on a boat that is properly installed.

I disconnect the link cable between the 2 panels - it is the normal waterproof solar plug & socket. I would ideally do it before the sun is up so no voltage. But I have not needed to isolate the panels from the controller since I installed them.

[Graham.m]

I disconnect the link cable between the 2 panels - it is the normal waterproof solar plug & socket. I would ideally do it before the sun is up so no voltage. But I have not needed to isolate the panels from the controller since I installed them.

 

That is the problem the need to do it is no a normal action so people do not see the need to design in the isolation.

 

Removing one of the link cables would seem to be a reasonable route. I do worry that the panels could be live and should the male connector touch earth/boat's hull there could be a circuit between the hull and one leg of the panels. Hence why I believe there should be an isolation switch.

Edited December 14, 2015 by Graham.m

[FadeToScarlet]

 

That is the problem the need to do it is no a normal action so people do not see the need to design in the isolation.

 

Removing one of the link cables would seem to be a reasonable route. I do worry that the panels could be live and should the male connector touch earth/boat's hull there could be a circuit between the hull and one leg of the panels. Hence why I believe there should be an isolation switch.

I have two large isolators for my solar panels, they double up to keep me warm on cold evenings because they're blankets.

[nicknorman]

I have two large isolators for my solar panels, they double up to keep me warm on cold evenings because they're blankets.

No greenie for you, sorry!

[Graham.m]

I have two large isolators for my solar panels, they double up to keep me warm on cold evenings because they're blankets.

 

Bit surprised at a Mod making that sort of remark. May sound a good idea, until it needs to be done in a force 4/5/6 wind. Then there is the boat with 6 panels or stick down panels or even 12 panels.