PV panels and fault voltage.

[kippaxkid]

Hiya,
I know rockall about PV, and they are due to put one on our building soon. This has been given to outside sources so we have had no input, and even if I had been asked I'm not sure what I could have contributed. But it still scares me, as the company involved have been used to installing on domestics, and are now stepping up to a 50Kw on a metal barnd style building with metal doors. You get the picture.
All the existing bondingand earthing is bob on, but I cannot see that as an antidote to the squeaky bum. That will just disconnect the main supply. It won't block out the sun.
If the cabling from the PV array is allowed to enter a building through a metal clad wall, and if the only isolation point is above the inverter,( some 10 metres from the input point, which bit trips in fault condition? Surely it should have a seperate fused isolator at the mains input position?
or does the panel shut down if it detects a short, and if so, how long after seeing it does it shut down?

Curiously yours

Chris :thinking:

 

[Graeme Harrold]

Electricity is a weird thing and will want to get back to the point of origin e.g.back to the panel. If for example the pos cable is cut to the shed clading, you are likely to get a tingle, unless you make contact with the neg! Solar panels are self limiting on current, and therefore unlikely to trip fuses for the purposes of fault protection.

The entry point and cabling should be adequetly protected for the environment it is in, and If you end up with bare cable coming through a drilled hole, get it done properly. Ask your installer these questions and see what the tell you.