Adding UPS to UK ring main

[MisterB1959]

@houseofancients
@SeaGal
and anyone else UK based who may be able to advise

Sunsynk 5kw ECCO Hybrid inverter installed in an outside utility
UK ring main in house

I am looking to have an essential circuit in case of grid failure. The circuit is an existing UK ring main. Would I need one Finder 62.82.8.230.0000 relay or two (one for each 'leg' of the ring main)? I understand there is a delay built into the Sunsynk before the UPS is 'live' but if the grid comes back on, would one relay be sufficient and operate quickly enough or would I need two relays, one for each 'leg' of the ring main. The relay(s) will be fitted adjacent to the consumer unit, BEFORE any sockets are supplied.

I will if course have an earth/neutral bond installed at the same time, adjacent to the inverter.

Although I will use a competent person, I still like to understand how it all 'integrates' ...

Thanks for reading

 

[houseofancients]

@houseofancients
@SeaGal
and anyone else UK based who may be able to advise

Sunsynk 5kw ECCO Hybrid inverter installed in an outside utility
UK ring main in house

I am looking to have an essential circuit in case of grid failure. The circuit is an existing UK ring main. Would I need one Finder 62.82.8.230.0000 relay or two (one for each 'leg' of the ring main)? I understand there is a delay built into the Sunsynk before the UPS is 'live' but if the grid comes back on, would one relay be sufficient and operate quickly enough or would I need two relays, one for each 'leg' of the ring main. The relay(s) will be fitted adjacent to the consumer unit, BEFORE any sockets are supplied.

I will if course have an earth/neutral bond installed at the same time, adjacent to the inverter.

Although I will use a competent person, I still like to understand how it all 'integrates' ...

Thanks for reading

I am not quite sure what you mean or why the relay is need ( except maybe anti-islanding)

Your sunsynk has 3 ports
Grid -> should go into grid port on inverter
Load -> should go to your home breaker panel
Aux port -> could be used as a smart port ( e.g. when battery > 90% and pv > 2 kw : enable port)

If grid fails, that port will be completely disabled, load port will stay energized by battery and pv

 

[MisterB1959]

Thanks,

i dont want the whole house feeding through the load port, just one circuit (which happens to be a ring main), which would normally be supplied through the consumer unit during normal grid connection.

when the grid fails, i want the load port to supply just the specific ring main, as an emergency power supply (UPS?) - i wanted to achieve that by using a normally closed relay, so that when the grid is on line, the grid actuates the coil , power flows through the relay into the ring main and is grid supplied and no power flows through the relay FROM the inverter.

when the grid is not available, the coil deactivates, and allows power from the inverter to feed into just the ring main. my question is, do i need two relays, one for each 'leg' of the ring main.

 

[houseofancients]

Thanks,

i dont want the whole house feeding through the load port, just one circuit (which happens to be a ring main), which would normally be supplied through the consumer unit during normal grid connection.

when the grid fails, i want the load port to supply just the specific ring main - i wanted to achieve that by using a normally closed relay, so that when the grid is on line, the grid actuates the coil , power flows through the relay into the ring main and is grid supplied and no power flows through the relay FROM the inverter.

when the grid is not available, the coil deactivates, and allows power from the inverter to feed into just the ring main. my question is, do i need two relays, one for each 'leg' of the ring main.

Yeah, that is not the way to do it properly.
If you want 1 circuit on the load port, create a critical loads panel..

What you are suggestion might work in theory, but has the potential to blow up your inverter or worse cause a fire, should you make a wiring mistake or something fails..

Sorry but can't give you advise should you push your idea onwards

 

[MisterB1959]

thats why i am on here asking !!!

is there a you tube session on creating a critical loads panel, rather than ask questions that have been answered elsewhere?

 

[houseofancients]

Critical loads panel is nothing more than a (usually smaller) main distribution breaker box containing the circuits that are absolutely required in case of a grid failure ( I think In you case it would contain 1 mains breaker and 1 circuit.

It would be fed by only the load port .

Don't forget to take care of the neutral ground bonding in that critical loads panel as your 5.5 does not have a buildin anti-islanding relay, so you would need to take care of that yourself.

Would advise you to have a sparky do that install for you, as it needs to be done up to code, or your insurance or city may give you lots of grief

 

[MisterB1959]

Thanks, i assume the critical loads panel, would be similar to a consumer unit, only the 'input' would come from the inverter, which in turn would be supplied by either the grid or by battery when the grid is not available - i didnt realise that the 'load' from the inverter was on at all times, i only thought it became live when the grid dropped out?

as it happens i have a relay arriving today that will be part of the neutral ground bonding (along with a fuse to protect the cable to the coil as explained in one of Keiths youtube videos)

 

[SeaGal]

Although I will use a competent person, I still like to understand how it all 'integrates' ...

They all say that ...

I have a Solis (actually 2 Solēs), not Sunsynk. Issues to consider will be earthing arrangements -are you TN-C-S or TT - and RCD protection for your critical loads circuit.

Re:

i didnt realise that the 'load' from the inverter was on at all times, i only thought it became live when the grid dropped out?

For comparison... the Solis AC-backup circuit is on all time that the Solis is powered, either from grid (if present) or from internally generated AC output (if grid is down). If there is no battery or PV supply, then Solis powers down and the AC-backup is disconnected, even if grid power is available.

 

[MisterB1959]

TN-C-S - from what ive been reading, both here and elsewhere, this is a job for my electrician ,,,

 

[SeaGal]

TN-C-S

I'm not a sparky, but IMHO you will need an earth-rod to provide earth on your backup CU, provide N-E bonding if the Sunsynk does not provide that automatically and an RCD for protection on the backup output of the inverter. Happy to be corrected by those who know more about earthing arrangements than I do... @shavermcspud & @mikefitz spring to mind

 

[shavermcspud]

TN-C-S is a combined N to PE at the point of supply plus PME along the supply line. As @SeaGal has stated you will require a separate Earth Electrode installed. the Sunsynk does have relay output to do this for you. Depending on what model/size Sunsynk you have, they have a full bypass mode so all house loads can in effect be placed on the Load side and grid can be fed in to the grid side, in this scenario you would only need an earth electrode tied in at the MET in addition to the supply earth. This would give you full off grid capability with Earthing already in place.