Add Panels on Steel Tech Shed

banie01

Following this one with interest as part of my own plan for my panels is splitting my panels across 2 south facing roofs. 1 on the house and the other the south aspect of a Steeltech shed. The consumer unit in the shed is earthed via 10sq back to the main house. I'd never considered a 2nd earth rod for the shed might be needed 🤔

10-10-20

https://www.boards.ie/discussion/comment/120490888#Comment_120490888

To be honest, I don't think that an additional earth-rod is needed, I was just mentioning that it was a possibility. It's all to do with the fault path - the path which mains voltage would take in the event of a short to the shed or the solar mountings. This fault path needs to be directly from the shed and along the CPC/earth in the supply cable and then directly through to the neutralising link at the meter (or so I understand). Any other path could compromise the RCD protection to the shed and microinverters, creating a voltage hazard. Let me create a question on the electrical forum and refer it back to this conversation and see where we go with this.

At the end of the day we all want our microinverter circuits to be as safe as we can possibly make them, but earthing and bonding are massive elements which we can't afford to overlook.

I did find an agreement cert for the Solartricity systems (string inverters and microinverters. There is mention of earthing the metallic parts of the solar system in accordance with IS 10101, but this does not specifically refer to microinverters and then also says "In general, where there are no adjacent metallic elements of the building (e.g. structural steel or piping) that are connected to the building earth, no additional equipotential bonding or connections to building earth are required.". A shed, would, in my mind be a adjacent metallic element.

https://static.solartricity.ie/wp-content/uploads/2020/07/IAB0200423-Solartricity-PC-Solar-Cert.pdf

Let's see what we find out.

bullit_dodger

I'm of the same opinion 10-10-20 (love the name btw). Earth is earth, so routing back via your consumer's (house AC earth) should be the same. That said, if there was something that I'm missing for example some ELCB vulnerability where you could get "trips" from some leakage from the DC side, I'd like to know that. The documentation/information I've seen on the topic seems misleading/confusing. So appreciate the question being asked here.

However, I think the main thing is to make sure that the rails & panels are earthed in some fashion. House's AC earth or it's own DC earth for the shed. That's the main thing

I am a little different from you though. I don't have rails. My panels are screwed onto 2x4's for me, which in turn are affixed to wooden mountings, and they are connected to wooden rafters inside the dual layer perspex roof, on a cement shed. So I wouldn't have the same path to earth as you would. That said, I wouldn't want a 50v charge on the panels either, should I ever go up on the roof to check something and get zapped :-)

allinthehead

https://www.boards.ie/discussion/comment/120489269#Comment_120489269

The panels are bonded using the 6 sq, from the house and the shed then needs to be brought to the same potential as the panels. So all connected to the 6 sq and the steel wire armour. It's essentially connected anyway through the bonding on the mounting rails.

allinthehead

https://www.boards.ie/discussion/comment/120489782#Comment_120489782

Ya the same thought crossed my mind, and from the reading I did on this, I came to the the conclusion that the panels are no more likely to be hit by lightning than any other part of the house. A type 1 surge protector would help but a direct strike would probably destroy everything. It should protect against an indirect strike. I would like to speak with a lightning protection expert on this, as it wouldn't cost much to add a lightning rod and a bit of tape.

allinthehead

https://www.boards.ie/discussion/comment/120490888#Comment_120490888

You definitely shouldn't be adding a second separate earth rod on a tncs system, I assume all of this second earth rod confusion comes from Uk forums etc, as they often have TT systems. We have some, but they are rare now.

Gerry

Everything I'm reading including 10 10 20s posts here and in electrical forum is suggesting that separate earth for shed just isn't done in Ireland. Ive 3 core swa out to the shed, the inverters are actually an earlier revision, they do need grounding. They suggest ground via separate swa or direct to racking and I have the washers so the latter is what I will do, then bond panels and racking to ground via existing swa/cpc .

dmboards

Hi guys,

A little late to this one but have a question - what roof pitch do any of you guys that have installed on a shed have?

I'm building a shed at the moment and the pitch will be around 20 deg and I know this is not ideal. Just wondering if anyone has experience or comments - one solar company told me that the panels would go on the roof without additional mounting to increase the pitch

Thanks

DM

Mr Q

https://www.boards.ie/discussion/comment/121487967#Comment_121487967

I have panels East/West on a steel roof. It's about 15 degrees.

Fitted without changing the panel angle with some of the short rails screwed to the sheeting.

unkel

https://www.boards.ie/discussion/comment/121487967#Comment_121487967

It really makes very little difference. The only issue is if the angle is less than about 10-15 degrees, then the panels don't "self clean" as well anymore

graememk

Mines on something like a 12 degree pitch, fantastic in summer, not great on the sunny winter days though

graememk

Haven't been near them since jan21. Look clean from afar

10-10-20

https://www.boards.ie/discussion/comment/121487967#Comment_121487967

Mine are at 15 degrees on a Steeltech shed. Haven't noticed any dirt other than a few leaves which have come off quickly enough.

I notice though that the shed has slightly less generation in Nov and Dec than the roof panels at 35 degrees, but it has been very mixed in terms of generation during Winter anyway.

daheff

how are you guys connecting the panels to the consumer unit? just run a cable under the garden and then along the outside of your house?

10-10-20

https://www.boards.ie/discussion/comment/121489718#Comment_121489718

Microinverter into a socket as the shed is already wired for mains. It's only a 700w microinverter in my case, not a mini-power-plant like graememk. 😁

graememk

https://www.boards.ie/discussion/comment/121489731#Comment_121489731

Only 8kWp on that roof.

Mine, comes off roof, into fireman, goes onto 6mm² 5 core SWA, 50m to barn where the consumer unit it, inverter beside consumer unit.

SteelyDanJalapeno

https://www.boards.ie/discussion/comment/121489718#Comment_121489718

I went under garden into the garage and then along the eaves to the consumer unit

daheff

yeah theres no way the wife will let me do this!!!

daheff

https://www.boards.ie/discussion/comment/121489731#Comment_121489731

could it go into an outdoor light?

10-10-20

https://www.boards.ie/discussion/comment/121494190#Comment_121494190

Nah, that's mixing lighting and generation. Best off a socket circuit.

allinthehead

https://www.boards.ie/discussion/comment/121494190#Comment_121494190

Technically it can go into any cable so long as it has 230v. It will work but it's not kosher. Micro's should have a circuit of their own with local Isolation.

dmboards

Thanks guys for updates on pitch for shed roof (sorry for slow come back). Go the shed built over the past few weeks but to only have about a 7 deg pitch (long irritating story as to why it not more). One solar company said it doesn't matter so long as there a pitch to allow them to self clean. Others didn't mention it if I didnt.

But a second issue was mentioned by one solar company - the distance between the inverter / battery and panels.

I want to put battery in the shed with 4 panels on the shed and 6 on the house which would leave the house panels approx 14 metres from the inverter/battery .. but the company said that the inverter/batter must be within 6 metres of the panels which would not be the case for me.

Anyone else heard this?

Thanks again DM

ColemanY2K

I know the battery has to be close to the inverter but never heard anything before about panels having to be a certain distance from the inverter.

I have a similar setup to you with the inverter in the shed. I'd be interested in an answer as the electrician is due to wire the setup shortly.

graememk

https://www.boards.ie/discussion/comment/121643982#Comment_121643982

My panels are 50m away from the inverter 😂

They did use a 6mm2 SWA to go from panels to the inverter (5 core, 2 strings+earth)

dmboards

Thanks guys ... it was first guy on phone from the company that mentioned the distance ... a different chap came out for a site survey and he didn't mentioned distance and has provided a detailed quote ... I'll ask again in my response to their quote which just came on Friday morning. So maybe its not and issue (or else I misheard what the phone guy was saying).

This has probably been covered elsewhere but apparently I wont get a grant if I put some on the shed cos those panels wont be 500mm from the perimeter apparently .... great ... but anyway I'm trying to get a good solution for my house and needs so funding is (important but) a secondary issue ...

When I clarify about the distance I'll update

Cheers

keno-daytrader

I have 2 strings and the inverter is 15m from one of my strings.

Also the 500mm is in relation distance from solar panel to edge of roof structure (250 from ridge tile) to qualify for the grant. Nothing to do with inverter. Not sure if that was the question?

Let us know how you get on.

10-10-20

https://www.boards.ie/discussion/comment/121644823#Comment_121644823

So have the installer install all panels in one go but only apply for the grant on the basis of the "legally" installed panels. The installer will just need to split the bill into two, no big issue and you remain above board.

delmonte4

https://www.boards.ie/discussion/comment/120483918#Comment_120483918

Looks a fine job. I'm looking to do something similar at the back of the garden on an existing patio and also on my steel shed. What size panels did you use on the pergola and also the steel shed? Did you have to put concrete footings in under the patio slabs or how did you do it?

allinthehead

https://www.boards.ie/discussion/comment/121716480#Comment_121716480

Thanks, 400 watt panels.

I dug out a decent size hole under the slabs, filled with concrete and used chemical anchor to affix.

delmonte4

Thanks for getting back to me. I’m trying to get a dividing wall built at the moment in place of a crumbling concrete post fence and want to amend my patio/walled flowerbeds to get the footings and posts where I want them. So I’m going to stick some panels on the steel shed which is east west in the mean time. You don’t know the dimensions of your panels by any chance? Have you a means of recording what you generate?