How much can I practically/legally DIY, and other newb questions

[Oldgreybeard]

The 16A rating will apply if just using a single pole of the switch, the series connection just allows the switch to handle the full 450V it's rated at.

Because there is no zero-crossing as with AC it is much more difficult to extinguish the arc at the contacts when breaking a DC circuit.

IIRC these isolators were originally designed for AC and they have had to use 4 contacts in series to reliably disconnect 450V DC. (The Kraus + Naimer ones are very similar, for the same reason.)

Hence it is good practice to switch off the inverter at the AC isolator first, then when you switch the DC isolator off there is no DC flowing so the contacts don't get eroded.

Indeed, hence the ~225V DC rating per contact for DC, 450V DC rating for two contacts in series. The current rating, though, is set by the current carrying capacity of the contacts when closed, so whether just one or two in series it remains at 16A.

[sharpener]

Indeed, hence the ~225V DC rating per contact for DC, 450V DC rating for two contacts in series.

It's worse than that. It needs a total of 4 contacts in series (3+1 or 2+2 as per the wiring diagram), so the individual contact gaps can only safely handle 112.5V.

[sharpener]

Standard way to isolate DC from panels is one of these: https://www.cef.co.uk/catalogue/product ... lator-ip65

I've bought one of these DC isolators, waiting for other stuff to arrive. Have actually ordered panels! Exciting times

But a question about the isolator, if anyone can help - it's a 4 pole switch, but comes with 2 link wires that effectively make it 2 banks of 2 switches wired in series. The diagram from the instruction book below shows what I mean (bottom left, "provided pre-wired linking").


[/quote]

By coincidence the electricians who came yesterday use both CEF and specifically the Scame isolators. But they sucked their teeth when confronted by a Kraus + Naimer one - even though the series contact arrangement is virtually identical - because I had positioned it for bottom entry, top exit and there isn't a specific drawing for that!

[dangermouse]

By coincidence the electricians who came yesterday use both CEF and specifically the Scame isolators. But they sucked their teeth when confronted by a Kraus + Naimer one - even though the series contact arrangement is virtually identical - because I had positioned it for bottom entry, top exit and there isn't a specific drawing for that!

Tell him to turn the diagram upside down

As this thread is sort of "my journey into solar power", here's a picture of my panels, which arrived yesterday. They're not getting much sun in this position though ...

[Joeboy]

By coincidence the electricians who came yesterday use both CEF and specifically the Scame isolators. But they sucked their teeth when confronted by a Kraus + Naimer one - even though the series contact arrangement is virtually identical - because I had positioned it for bottom entry, top exit and there isn't a specific drawing for that!

Tell him to turn the diagram upside down

As this thread is sort of "my journey into solar power", here's a picture of my panels, which arrived yesterday. They're not getting much sun in this position though ...

Congratulations, that is a huge step. DId you have enough sun to voltage test them Pre store?

[dangermouse]

I'm waiting for cable and connectors to arrive (DPD are being crap) then I'll lay the panels out on the lawn and connect them up. If the weather stays clear then I should get a few hundred watts at midday, which should be enough to test everything.

Then just waiting for a day when it's not too frosty to go on the roof!

[Joeboy]

I'm waiting for cable and connectors to arrive (DPD are being crap) then I'll lay the panels out on the lawn and connect them up. If the weather stays clear then I should get a few hundred watts at midday, which should be enough to test everything.

Then just waiting for a day when it's not too frosty to go on the roof!

Now that, sounds like a plan!

As a matter of course, I check each panel before beginning. Gives me a datum line to go from before I chuck em about.

[Oldgreybeard]

I'm waiting for cable and connectors to arrive (DPD are being crap) then I'll lay the panels out on the lawn and connect them up. If the weather stays clear then I should get a few hundred watts at midday, which should be enough to test everything.

Then just waiting for a day when it's not too frosty to go on the roof!

Thanks, that's given me the same idea! I'm still waiting for the promised help to get my six new panels up on the frame I've put on the wall, but it makes a lot of sense at the moment to just prop them against the wall and wire them up, as at least that way I'll get something.

[dangermouse]

Well I never got chance to do a test run of the panels (spent most of Xmas fixing my father's central heating), but now they are on the roof!

8 x Canadian Solar 410W from Bimble. Been a bit grey since they went up, except for yesterday when the sun poked through and I got a whopping 3.7 kWh.

Now I have to resist the temptation to obsessively check the generation every time the sun makes an appearance

[ducabi]

What's your approach to installation? Have you got roofer with scaffolding or just everything diy? Have you checked the roof can support the weight? It's all still ahead of me.