Surge protection, fuses and MCBs in loft from PV array.

[JohnMo]

12 minutes ago, Beelbeebub said:

My inverter has instructions to turn the inverter off

ALL inverters need the AC disconnect, prior DC. Big bangs likely in full sun if you don't.  Likely to need a new isolator switch if your lucky, if your not, big volt DC isn't good for ones health.

 

[jimseng]

Quote

if you were desperate to have a "disconnection" point on the loft

I don't think it is really about having a disconnection point in the loft. I started this thread wondering if there was any point in having the SPD/Fuse/MCB box in my first post. I have concluded that it isn't as @Dillsue pointed out, what is the point of a fuse given the short circuit current of the panels? So I think I will stick with MC4s and buy a cheap crimper for the 8 terminations or so I will have to do. This seems the safest way to make the connections over any period of time, day or night when I come to it.

[JohnMo]

Just looking back at the original post on this thread the box shown is a combiner box, so takes two parallel strings and brings them into one. So you double the amps. So may not be suitable anyway.

 

Your other question is are you have string fuses? If so have them in a DIN enclosure in loft or anywhere as an easy place to terminate the strings. Terminate the other side of fuse and take to the inverter.

 

 

[Beelbeebub]

26 minutes ago, JohnMo said:

ALL inverters need the AC disconnect, prior DC. Big bangs likely in full sun if you don't.  Likely to need a new isolator switch if your lucky, if your not, big volt DC isn't good for ones health.

 

There is a whole shutdown sequence including shutting down the bms etc etc. My point being it's fairly easy as all the isolators (AC and DC) switches and buttons are in one place. 

 

If there is a loft isolator, before it can be turned the operator has to go down stairs do the various operations before coming back up. 

 

There is, unless the isolator is locked on, a fair chance someone will just turn the knob possibly under full load. 

 

Much less likely if the isolation requires opening a box (with a tool) and then using another tool to disconnect the MC4s

[Alan Ambrose]

Is there a vague 'requirement' for a fire-brigade-accessible PV-shutdown switch. I'm thinking a big red stop switch in an obvious place, probably wired to the inverter or a DC-contactor? Would this be sensible or is it completely OTT?

Edited 17 minutes ago by Alan Ambrose