2 inverters

[lee foster]

Hi , I have a PV job that requires 2 inverters due to different array orientations , each array will be 1715kWP , can i put both inverters on the same AC circuit as betwen them they are under 16A? or do ineed to run a circuit for each inverter?.
Thanks in advance.

Lee

 

[bumcrack]

you mean wp?

 

[lee foster]

ok wp!!

 

[johndpar]

Surely Wp, Mr Watt might be offended!


And the inverters could probably go on the same circuit if all the wiring is rated for 16A, but make sure each has its own AC isolator.

John

 

[lee foster]

Hi John , Wp absoloutley correct , thanks for the help think i'll go for the 1 AC Circuit with seperate isolation.

Thanks again much appreciated.

Lee

 

[bumcrack]

I would check that you can do that. My understanding is that every cable needs its own protective device, unless they are parralell feeds to the same loads ???

In any event a small sub board with 2 x 10a MCS would do it.

 

[sharpener]

As well as sizing all the cables for 16A you also need to check the maximum fuse/mcb rating of the individual inverters as this may be less, in which case it's the sub-board...

 

[moggy1968]

If you run them both into their own isollators, then join the AC cables that connects them in parallel, adding the 2 current levels together but keeping the voltage the same. no problem putting them both on the same MCB as it's under 16A and they are radial circuits.

 

[lee foster]

Thanks for the replies , i'm going to check with the Manufactuer of the inverters , hopefully they can clear it up for me.

Thanks again

Lee

 

[edexlab]

What inverters are you using ?
most of the manufacturers advice I've seen specifies that each string inverter should be on its own Mcb

(I'm thinking that you are trying to use one meter for both inverters , if this is the case I would run tails from Henley block to a main switch through the meter to a two way consumer unit then to two Isolators one for each circuit/inverter)

also in the Dti guide it says ''An inverter supplied from a Pv array must preferably be installed in a dedicated circuit''

 

[lee foster]

Hi edexlab , Mastervolt inverters as i can't get SMA at the moment , i think i'm just going to put 2 radials in and be done with it , the C/U is only a couple of meters away from the inverter location anyway , would you consider 2 meters one for each inverter?.

Thanks for the info.

Lee

 

[bumcrack]

The other thing to consider is redundancy, if two inverters are fed from one MCB, and one faults, you lose both inverters.

As for radial circuits, does this only apply to fixed equipment that's fed from a fused spur or socket?

 

[moggy1968]

There is no need to fuse down a radial circuit to feed sockets using a SFS, you can just use an isolator, you can run any number of 'spurs' from a radial circuit which can be taken at any point along it's length, including at the consumer unit. There are of course the issues of demand and floor area to consider though.

Other wise I think it depends on your interpretation. I would regard the solar array as a single installation, even if it has 2 inverters and 2 strings, so feeding both from one MCB is acceptable, but I think that is open to interpretation.
Otherwise you would need 2 meters as well and theoretically I could see a problem with this then being considered as 2 installations at the same address.

 

[bumcrack]

But radial circuits only apply to socket outlets?

 

[GreggElectrical]

Surely one circuit is fine. Apart from anyone's interpretation of the DTI guide can anyone think of any reason why not?

The earlier comment about if an inverter has a fault you will lose both is a bit questionable. How often will thus happen and surely you will just turn the isolator off for the faulty inverter?