Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. angel While you're here, would you mind checking out our Electrician's Insurance section to see if we could save you a few quid? - Specifically our Van Insurance Deals and Public Liability Insurance Deals. Thanks for supporting the forum! angel

    5% Discount from Electrical2Go.co.uk for ALL members! - Click Here

  3. Forum for Trainees.

    If you are a trainee and haven’t already applied to join our trainee forum then click HERE The trainee forum is a closed area of the forum where the Forum Mentors will freely share their vast experience within the industry. 

    Dismiss Notice

DC fuse blowout

Discussion in 'Solar PV Forum' started by Lionscourt, Jun 23, 2016.

Discuss DC fuse blowout in the Solar PV Forum area at ElectrciansForums.co.uk.

Thread Status:
Not open for further replies.
Please make sure you checkout our forum sponsors, many do discounts for members and, they keep the forum free to use.
  1. Lionscourt
    Offline

    Lionscourt EF Member

    I was asked earlier this week to look at a solar system on an office/warehouse that had stopped working (not my install). The strings all come into a Fronius DC box on the roof. When I opened it up it was pretty clear why the system had stopped producing:

    Fuses 1.jpg

    I'm looking for opinions on what may have caused this so it won't happen again. Why are 3 of the sets of fuses blown but not the fourth? Could lightning have been involved, or was it something more mundane?
     
  2. SibertSolar
    Offline

    SibertSolar Solar Guru

    Location:
    Hampshire
    Business Name:
    Sibert Solar
    Direct, or induced, surge most likely I'd imagine. I can't imagine that the fuses were rated incorrectly. Any Type2 or Type1 devices fitted to the DC circuit on the array-side of the combiner box? Was the array frame earthed/bonded to the MET? Any damage to the inverters?
     
  3. Lionscourt
    Offline

    Lionscourt EF Member

    Thanks for the reply SiberSolar. I still have some investigating to do, but what I know so far: There are no SPDs fitted between the arrays and the box. The panels are spread out in three lots on a metal roof, with nothing earthed back to the MET. The inverters don't appear to be damaged, but I haven't fully tested them yet.
     
  4. davesparks
    Offline

    davesparks Forum Mentor

    Location:
    guildford
    It looks to me like a fuse has failed to clear a fault correctly and caused a flash-over taking out multiple adjacent units.
     
  5. SibertSolar
    Offline

    SibertSolar Solar Guru

    Location:
    Hampshire
    Business Name:
    Sibert Solar
    Can you check the remaining fuses to see what size/type/rating they are perhaps?
     
  6. Lionscourt
    Offline

    Lionscourt EF Member

    Fairly certain they're Littelfuse 15A Midget Fuse rated at 600V, at least that's the partially-empty box I was given by the client.
     
  7. SibertSolar
    Offline

    SibertSolar Solar Guru

    Location:
    Hampshire
    Business Name:
    Sibert Solar
    Ok, doesn't sound like gPV fuses to me....do you know what the panel spec is, and the string config?


    Sent from my iPhone using Tapatalk
     
  8. Lionscourt
    Offline

    Lionscourt EF Member

    They are labelled as "Fast Acting gPV Photovoltaic Fuse". I don't have the panel or string info at the moment.
     
  9. mechelec
    Offline

    mechelec Electrician's Arms

    Location:
    Here
    Lightning strike ? Seen it before.
     
  10. Lionscourt
    Offline

    Lionscourt EF Member

    Anything that can be done to prevent it, assuming it was caused by lightning? Would having the array earthed back to the MET help to prevent a blow out like this?
     
  11. Gavin A
    Offline

    Gavin A Electrician's Arms

    Location:
    Leeds
    Business Name:
    Leeds Solar
    erm, is that 4mm2 cable used as the link from the fused combiners?

    fuse combiners that look to be combining 5 circuits, each running at say 8 amps = 40amps running through a single 4mm2 cable continuously for hours on end.

    Assuming that this is a system with standard mono / poly panels and not something like solar frontier thin films, then the answer to the question is incompetence (I assume it's clear what I'm getting at).

    Also probably not tightened fully on the burned out sections would be why they burned out rather than the left hand neutral combiner.
     
    • Like Like x 2
  12. saggers
    Offline

    saggers Active EF Member

    Could be a loose connection overheating. I've seen this before on normal electrical circuits and the heat seems to spread to connections close by.
     
Loading...
Similar Threads - fuse blowout Forum Date
Totally confused - converting dimmers to switches Lighting Forum 43 minutes ago
Pump / battery and fuse advice Electrical Forum Friday at 12:22 PM
Thread Status:
Not open for further replies.

Share This Page

Electricians Directory Post a Domestic Job Post a Commercial Job