After some advice please TPN supply with single phase PV install

[sythai]

Hi Guys

I don't much about PV being honest, we normally just leave space on DB for the PV installers to do their thing.
Sometimes having to run a cable to the inverter location.
Never really hear anything about it after that.

Apart from recent new build which has TPN supply/ DB and PV was installed as single phase system.

Home owner has been complaining that their system isn't running as efficiently as expected.

After some advice please as 'PV installer' is trying to steer some of the blame towards us, saying we could have wired it differently:
" install as much possible (load dependant) on the same phase as the PV System"

On all the domestic TPN new builds we've done over last few years only ever been given 63a/ per phase so can't really see this being an option.

Wouldn't it have been better for them use a TPN PV system? Or are their limitations to this sometimes.

I've got the builder (decent guys who I want to keep happy) on my case asking how we can prevent this happening on future jobs.

Thanks Sy

 

[PS Electrics]

Hi Guys

I don't much about PV being honest, we normally just leave space on DB for the PV installers to do their thing.
Sometimes having to run a cable to the inverter location.
Never really hear anything about it after that.

Apart from recent new build which has TPN supply/ DB and PV was installed as single phase system.

Home owner has been complaining that their system isn't running as efficiently as expected.

After some advice please as 'PV installer' is trying to steer some of the blame towards us, saying we could have wired it differently:
" install as much possible (load dependant) on the same phase as the PV System"

On all the domestic TPN new builds we've done over last few years only ever been given 63a/ per phase so can't really see this being an option.

Wouldn't it have been better for them use a TPN PV system? Or are their limitations to this sometimes.

I've got the builder (decent guys who I want to keep happy) on my case asking how we can prevent this happening on future jobs.

Thanks Sy

There isn't a right or wrong answer. 3 Phase or Single Phase would depend on a number of factors, Array size, loading, any 3 phase loads, budget etc.

The comment "install as much possible (load dependant) on the same phase as the PV System" Isn't very helpful. It might have been prudent to have clarified this with them, hindsight and all that! Could also argue they should have been a bit more involved than just saying what they did. After all they are the designers of the PV and it is critical the right loads are connected to the PV to make the most of it.

Ideally they should have given a list of circuits to be on the PV Phase or desirable to be on the PV Phase. Then it would be a case of seeing what can be accommodated within loadings and balancing of the phases.

Decoding that comment to me reads the Customer is doing it on a Budget. They should have gone 3 phase unless the array size or budget ruled it out.

You are going to lose efficiency (in terms of usage) having a single phase PV there is simply no way to avoid it, two thirds of your loads cannot use it. That would be the compromise in having single phase PV. Also like you said you are limited on what can go on a single phase, the loads are meant to be spread over the 3 phases to be as balanced as possible, It is good design practice.

 

[sythai]

Thanks PS.... do appreciate your advice.

Just so I understand a little better:

Was smaller array than usual on this property, could this have been a reason not to run it as 3phase PV ?
(if so why would that be please.)

 

[DefyG]

Home owner has been complaining that their system isn't running as efficiently as expected.

What was his expectations, the 1Ph/ 3Ph problem should have been explained to him by the PV installer at the design stage, whereby he could of made a choice to upgrade to 3phase!

You say you just run a supply for the PV system, what supply were you asked to install 1Ph or 3Ph?

The PV system is probably running as efficiently as it can (his App might show that). If in his mind it isnt efficient as it is not supply 2 thirds of his load, that is another problem, nothing to do with efficiency of the PV set up.

Was smaller array than usual on this property, could this have been a reason not to run it as 3phase PV

If array size is limited by number of panels that can be physically installed there would no point in putting a larger 3ph inverter.

How big an array kW?

 

[baldelectrician]

I have a 3 phase supply at home, I have a single phase sub DB for most of my domestic supply (this was going to be essential power DB if I got a battery with a small back up)

The solar PV goes directly in to the Sigenergy battery inverter (outside) and this feeds the house

I also have the Sigenergy 3 phase gateway which gives the whole house back up and 0ms switchover

The system has an earth spike to work on island mode

Also, under G98 the export allowance is 11kW on 3 phase