How do you wire your panels?

PvNewbie · Sep 7, 2011

I can't really find anything on this and it wasn't taught on the course but do/should you...

1) Wire the panels so a big loop is formed on the roof from +'ve to -'ve
or
2) Wire so that the loop is kept small and the +'ve/-'ve follow the same route around the panels using more wire and a bit more time consuming.

I hope that makes sense.

Newb

northernsun · Sep 7, 2011

I'm not too sure what you mean tbh!

My aim is to:
a) keep the cables/modules connected properly and in the right number for the strings- this is kind of a priority!
b)have them nice and neat, secured and invisible as much as you can.
c) make sure none of the cables are tight and stretched or snagging, using extensions if needed.
d) aim to have my point of roof penetration in the same place-rather than one at each end for example.

As long as you are in a proper circuit with them all correct and none missed out you should be fine, its obioulsy better to have less of a cable run- but not at the expense of having the cables stretching to be plugged in, or cables that are going to be rubbing on the array or even worse- trapped.

I think if you are an absolute beginner you will quickly see how it's best to do it when you're putting the modules on- it can differ depending on the layout or the module, just use common sense and take your time. Lots of people have different methods that work for them when connecting the modules- some stick all the panels on and then go along and connect and tie afterwards- although this is a problem when doing a few rows, some connect as they go along. I've worked with roofers (some of whom seem to have a mental block when the word electric is mentioned) draw out the connections in chalk on the roof- or got me to!

Hope that helps

BruceB · Sep 7, 2011

OP, I think what you are getting at is the area of the loop formed by the dc circuit. You are right that it should be as small as possible and somewhere in the DTI guidance I think there is a phrase along those lines or one that says outwards and return paths should be alongside each other. The reason you minimise the area is to minimise inductive pick up when you have strong magnetic field changes locally, for instance when lightning is close
Regards
Bruce.

northernsun · Sep 7, 2011

Or that. what he said!! ^^^^

PvNewbie · Sep 8, 2011

BruceB said:
OP, I think what you are getting at is the area of the loop formed by the dc circuit. You are right that it should be as small as possible and somewhere in the DTI guidance I think there is a phrase along those lines or one that says outwards and return paths should be alongside each other. The reason you minimise the area is to minimise inductive pick up when you have strong magnetic field changes locally, for instance when lightning is close
Regards
Bruce.[/QUOTE

That's right Bruce. Thanks. So yes, keep the +'ve and -'ve alongside each other!!??

TJLinks · Sep 8, 2011

I've another one, can you run two strings down one PVC conduit?

BruceB · Sep 8, 2011

Yes, as long as it will fit. Not different from ac in that regard.

TJLinks · Sep 8, 2011

do you take in to account the accumulative effect of DC voltage in each string, eg string 1@ 600v plus string 2@ 600v = 1200v (voltage rating of cable =1000v DC)