COC for PV installation

[Justloadit]

I once touched a solar panel where the diodes where already burnt out. Panel was melting hot.
On Google there are pictures of panels being destroyed / burning. Maybe it is the roof structure that produces the flames? Therein my incorrect use of "panels can burn". Melt is more accurate?

Solar panels when operating at full potential can exceed temperatures above 60 degrees centigrade, and touching the surface is a sure way of burning your skin. This is one of the reasons that PV panels should have an air gap of no less than 100mm from the back of the frame to the roof. It then allows convection cooling to take place.

If you could cool the panels down to less than 25 degrees then you will get another 10% more of energy out of it. Unfortunately there is no inexpensive way to do this, so we live with the reduction of energy with the heating of the cells.

Question: A electrician and a engineer both mentioned that earthing panels for lighting is not such a good idea, as you are supposed to use the same earth as the DB and that is just another path for some of the lightnings power, before the cable disintegrates, to get into the house. What is your take?

That is not good practice. If lightning strikes your PV panels, and you have a grid tie system, or any other system that may be running, the potential difference between the 2 earthing points could be a few thousand volts, due to the induced energy in the earth between the 2 earthed points. If you happen to be touching one of the copper water pipes, then the earth leakage is not going to save you.

Also the PV panels being on your roof, increases the risk of lightning affecting your installation.

My take on this is an earth strap from the PV panels to the shortest path to a earth via an earth spike. Then join an earth wire from the earth point on the PV panel and take it to the DB earth star point. This way there can be no potential difference between the two points, as invariably all water pipes in the house are connected to this earth, usually at the geyser position. If lightning strikes the roof or panels, it will immediately be directed to earth via the shortest path.

By joining the two earths, with a minimum of a 6mm square multi strand wire, or preferably a flat strap, then you negate this earth potential difference across the two points.

Fuses on PV cables are to protect the wire, in case there is a short of whatever cause, correct? I prefer fuses on Pos and Neg.
Have had a 10amp fuse installed on the wires to the panels. It burnt out when the panels reached full potential. Had to upgrade to 15amp fuse promptly, as the installer though 10amp is ample on 3 x 310w panels in series. It was a good solar day. :-)

A brand new panel will always provide more energy that the label states, and after the first few months of operation it will drop a few watts and come close to the PV panel label. Manufacturers do this to ensure that the panel performs according to the label.

A 315W panel will produce approximately 8.75Amps at 36V on a normal day, but if there has just been a bit of rain, which has now cleared the atmosphere of dust, and dropped the temperature a bit, it causes tinny droplets in the upper atmosphere which act as little lenses, and refract and increase the sun radiance some what, with the lower temperature of the cells, you could get another 20 or so watts out of the panel, and push the current up higher, and that could be close to the fuse rupturing point.

I have seen this happen as well on a cool crisp winter morning around 10H00, by measuring the power of the panel, I was getting the full panel rating.

I have read somewhere that you get MPPT inverters that are mounted per panel sending 220v down the wires to the central unit, which in turn is grid tied.

Grid ties inverters have galvanic insulation between the panel and mains supply, so that takes care of the isolation.

Back to the question I was aiming for: Where do homeowners with grid tied solar systems stand ito of a CoC for the DB install, being AC?
Is there is CoC needed for the DC side ito panel installs?
A normal electrician cannot give on, if I read the other posts correctly.

If the panel side is below 50V, then no COC is required. However the grid ties inverter must have a SANAS approval for it to be accepted as usable equipment, and installed according to the legislation, will allow the electrician to issue a COC.

Batteries are straight forward, you have to have a fuse and a quick disconnect. As I want to be able to move the battery bank, it is on wheels:
Would Brad Harrison connectors (same as at the Anderson connectors) be acceptable?
Hands are protected from the spark if you disconnect under load.

All battery banks should have a suitably rated "DC" isolator, in order that you can disconnect the battery in case of a problem. Using an "AC" isolator or circuit breaker is extremely dangerous, as they self distruct and catch fire if the circuit is disconnected under load due to the arcing of the contacts during the disconnection. Do a google search "AC breakers in DC circuits"" to see some frightening you tubes on the failures

ANderson connectors are good, provided they are rated for your installation.