Daisy chain inverters?

[edexlab]

I've just seen an install fitted 2 years ago and I'm interested in how this is G83 compliant! information regarding design etc is being forwarded to me later, but what they've done seems like madness/sheer incompetence to me

I'm going to call the company on clients behalf and hope they sort it as its a shambles this will be the 5th return visit from this firm

There are 2x Aurora 3000 inverters and one 3600, (not sure if Tl's or not i'll be checking later) each has its own Rcd and Mcb fed via 4 wy CU next to the inverters and the single phase supply is daisy chaining across each CU Rcd top terminals

System has worked without issues but recently the Rcd covering the 3600 is tripping out so customer called me in to have a look,

Other than what I've already mentioned above the cable feeding these has no isolation or relevant ocpd and is dogged into the incoming side of the DB main isolator , they've fitted 2 AC isolators next to each inverter and the supply goes through the Rcd (also daisy chained to the next Cu) and Mcb then through the meter and then to the first Ac Isolator and then the 2nd????

Also they have Dc cables in the same 50x50 trunking which I know is debatable re the insulation rating but something I'd not do.

9 feet away is the mains incomer with a 3 phase supply! it is such an easy job to have done better I'm staggered!

 

[SolarCity]

Do you have any pictures. I'm struggling to picture this.

 

[TedM]

If it is a 3-phase supply and the embedded generation is not balanced across the phases then that fails G83 straight away - unless there is some dispensation from the DNO but I would be surprised by that.

 

[edexlab]

I'm waiting for the design /system details and electrical certs from the client as she has hid them away somewhere, but my thoughts were

a) Install doesn't comply with G83, Mcs, Bs7671 and probably anything else you could think of.

b) Is she therefore at any risk of losing the tariff rate as it could be argued this system was never installed according to the requirements , leaving her to pursue the Installer for loss of revenue etc
It actually makes me mad as she paid good money from a so called reputable firm for this

I do have pictures and will post them this weekend, but its difficult to see exactly what's going on with the inverters supply (daisychained) , I tested the continuity as just looking and tugging wires became confusing very quickly
but you'll be able to see the doubling up of conductors in fhe Rcd terminals etc

 

[Worcester]

Are you sure they're not using a single phase board as a manually re-wired three phase board?

 

[edexlab]

No the existing main Db is definitely a standard 3 phase Db 4 pole main switch
As I said before the single line supply to the pv db's tapped off the meter side of the main switch as there were no spare ways available and a single phase db next to it with old type 2 mcb's and 2 spare ways, I accept that its hard to source these mcb's but even so they'd still be short one way.

Really simple job to have done properly by splitting the tails via henley blocks to feed a one way 3 phase db with an Mcb/circuit for each Inverter

Out of curiosity do you mean a single phase type enclosure with the removable busbars x 3 which sit together within the busbar guard in the same layout as a single phase board ?

I have used Schneider and I think it was Chint but these are supplied like this as 1 or 2 way 3 phase db's and not modified by an installer
Or are you talking about something someone has modified?

(Occasionally here you do come across a 3 wire single phase supply to a 3 phase board, the ones I've seen had nothing altered within the board they just used the red and yellow mcb ways only and labelled it as such)

 

[edexlab]

I've had a look for this company and they are a "National company" the type that tells its customers not to trust small companies
They have poor feedback due to bad installs , hard sell tactics and very poor customer service and the directors are/were? the owners of a company which did the same but with a different product which apparently got national press coverage

 

[Earthstore]

So who are they?

 

[edexlab]

If it is a 3-phase supply and the embedded generation is not balanced across the phases then that fails G83 straight away - unless there is some dispensation from the DNO but I would be surprised by that.

I've just spoken to the customer re paperwork of this job and She says She'll get it to me soon, but the interesting thing is they have an MCS Cert for each inverter?

I told her what I wanted to see ie MCS Cert , and she said "Oh yes I've got 3 one for each inverter"
Apparently when they complained to the Installer about the RCD tripping She was told

"No worries that's why we put 3 inverters in, in case one stopped working, You'd still have 2 more"

I have tried to post pics but having problems!

 

[Meggerman]

As you have already said it is never going be acceptable under G83 with all on one phase. How will FIT payments work with 3 MCS certs??

 

[whinmoor]

"No worries that's why we put 3 inverters in, in case one stopped working, You'd still have 2 more"

LOL - and don't worry if your car has a puncture - it'll be fine because the other three wheels are fine.

 

[TedM]

Try and get a copy of the G83 paperwork if the client has a copy. Be interesting to see how that has been filled in.

 

[SibertSolar]

The mind boggles!

 

[edexlab]

LOL - and don't worry if your car has a puncture - it'll be fine because the other three wheels are fine.

yeah i said
"we all keep 3 cars on the drive for the same reason!"

 

[edexlab]

Inverters

 

[edexlab]

Difficult to see here, Incoming Single phase direct to Rcd and then looped off to next CU along

 

[edexlab]

Swa not glanded one core chopped Black conductor/ earth taken to Isolator

 

[edexlab]

SWA rhs Line to incoming side of main switch

 

[edexlab]

Inverters are 9 ft away directly above ( space is not an issue)

 

[edexlab]

Nice label but I think the warning part could be clearer