Method statement & risk assesment for removing a broken module

[matt25]

Hi, I was wondering if anyone could share their knowledge in removing a module that is surrounded by many others on a roof. There is adequate roof access & mansafe points to harness to but it was more the electrical safety issues relating to isolation & removing a row of panels to access the damaged one. The array is an E/W mounted at 10deg on a flat roof so the client prefers removal of a few modules rather than walking over them, there isnt enough space between the modules to walk between them.
Many thanks in advance....

 

[Worcester]

Just think about it and write it ... what is the safe way ?

Presumably the installer also provided an 'as installed' string layout diagram as part of the hand over kit, identifying which modules make up which string, like we do.. That way you only need to isolate those strings that are affected and could even temporarily rewire strings to balance up the inverters if nscessary so that the rest of the site could continure generating.

Else you will have to isolate it all in case you unplug the wrong ones... on a sunny day, nice big sparks....

Rule 1: Do it the safe way.
Rule 2: Refer to Rule 1.

Question - any idea how the panels got broken? - which make are they? which mounting system? and when were they installed winter / summer ..?

 

[matt25]

Hi, thanks for your reply. Being the cautious type im considering the work at night with task lighting, do you think thats over the top, essential or just daft?! The safety of our electricians is paramount and i wouldnt be on site at the time as them. The manufacturers or any other info hasnt been disclosed yet but I'll let you know if we do the work. The only other module ive ever seen broken was a sharp one that had the glass shatered on the clamping point, ive got a photo somewhere if its of interest.

 

[solarsavings]

Why would you contemplate working at night?

 

[matt25]

minimising the risk of working on a sysem we havent seen, what would you do? obviously not that lol

 

[Worcester]

Working at night is twice as dangerous as working on a fully shut down isolated system

 

[telectrix]

helicopter?????

 

[Worcester]

The trickiest bit is putting the panels back in the middle of the row and all lined up nicely, whilst tie wrapping the cables back in place ... it's a tight fit..

 

[matt25]

Thankyou, i'll try the helicopter daytime isolated approach. So glad i asked, what could possibly go wrong!

 

[Gavin A]

maybe I'm being funny here, but erm, well, er how can I put this... I'm baffled at this thread even existing. If you're a solar installer surely this is just second nature, bit like a spark asking how to change a lightbulb.

One thing to watch out for though is idiots who think it's clever to wrap the cables around the rails instead of tying them, thereby making it likely that you'll end up pulling the cable out of one end or the other if you go to lift the panel from the opposite end the way the installer did it.

I'll add to worcesters golden rules.

1 - is it safe?

if yes, proceed, if no make it safe, then proceed if it's within your competence to do so.

 

[matt25]

Thankyou Gavin, im not an electrician and have very limited experience with solar so it is nice to have somewhere like this to ask what may seem basic questions, without too much sarcasm in the responses either!

 

[Gavin A]

ah, sorry my mistake, thought you were an installer asking that question. been a very long day / week.

 

[matt25]

no problem, i maybe read too deep into 4.3.3 of the installation of pv systems guide?

 

[Worcester]

4.3.3 Hints at large systems ....

Often there are not individual string isolators on the bigger systems, and it effectively may need the shutdown of a large central inverter. The lost revenue costs then, may actually mean it is more cost effectove to do it (safely) at night. For a 50kWp system using mutliple three phase string inverters, it should be possible to isolate the individual string, hence it is no longer live...