A non boaty question on doemestic solar PV sytem

[William_H]

I have a 1500w solar PV system at home and it worked well for some years. Due to a gov't incentive scheme no electricity bills just credit. I found myself ignoring it until suddenly I got an electricity bill. Found that the PV system was not working. No output from the panels. Finally found a box on the roof that contained 2 10amp fuses. One for positive one for negative. One was blown. I replaced the fuse with difficulty. It was rated at 1000v. reasonable with 300v normal output. Now all OK
I think or assume the fuse just failed from fatigue or age or something. (no vibration)
So my question ... Why are there fuses fitted anyway. In a short circuit the panels can only provide 5 amps. Is this some sort of lightning protection? The metal parts of the 8 panels are all grounded as a requirement. ol'will

 

[catmandoo]

Fuses are usually rated in amps ie amount of current they can carry until they blow regardless of voltage Panels after inverters or whatever are presumably connected to mains 240 volt system . Would suggest that fuses there to protectinverters and system should there be a short in th e line or other connections causing current to flow back

 

[Cardinal]

Will, I am glad that your small problem was so easily solved. Perhaps a spike in the mains voltage caused your fuse to blow?
I have a system the output of which could be monitored via a website until the manufacturer of the mini-inverters went bust. Now I have to watch for a winking red light on the meter which reassures me that the sun is having the desired effect.
I am surprised that your post has not provoked a number of expressions of envy. I wish my supply needs could so easily be met by a modest sized solar system!

 

[fisherman]

Any shorting on the DC side can cause arcing and a fire risk, maybe the fuses are for that. We went away for three weeks the day after our install and came back to find one of the two strings down and smoke stains up the inverter, due to a poor connection. I too have to watch the red lights flash to decide how my gen/use balance is going, as long as the PV meter is flashing quicker than the grid I’m ok.