UK grid-tied 3.68kW inverter connected to ring mains?

[dslrx9254]

Someone on the electrics... forum suggested that they might connect a small inverter to the ring mains or that there was already some product that does this. Naturally they were met with hostility as that seems the norm for that forum.

Specifically there was some bitching about this overloading the ring circuit. However these same people were very defensive when it came to overloading an RCD and attached cabled with more current than they were rated at. Mine has 3x32A circuits via a 63A RCD and cables apparently totally normal and safe as provided by the home builder and also passed via an official test report.

Anyway I doubt anyone will approve this type of setup but it doesn't hurt to ask if there is a official answer.

 

[fourtytwo]

What electrics forum was that then ?
Sounds like you are one of the headstrong "I will do what I like brigade".
My advice to you is either hire a qualified electrician to tell you the rules OR read them yourself, presently you seem to be seriously misinformed.

 

[MisterB1959]

im not actually sure about what you are asking (and certainly not a pro electrician)? perhaps a diagram/line drawing might help?

ive installed my 5kw inverter via a 6mm cable but i have a 3.66kw inverter installed as a solar installation a few years ago that os fed by 2.5mm cable. i questioned the electrician at the time, thinking a 4mm cable was more appropriate and his answer was the supply/draw will NEVER be more can be carried by a 2.5mm cable ..... so perhaps the suggestion to connect to a ring main MIGHT be a 'working' option, but as mentioned, i strongly recommend getting in a proffessional for their opinon if youre considering it ...

 

[dslrx9254]

What electrics forum was that then ?
Sounds like you are one of the headstrong "I will do what I like brigade".
My advice to you is either hire a qualified electrician to tell you the rules OR read them yourself, presently you seem to be seriously misinformed.

If I was going 'to do what I like' I wouldn't waste my time here would I. I would just get on with it because job can be done safely and in a cost effective way with much less effort than this. This is about getting it done in an approved way and signed off with Part P / BC if required. If you know it can't be done acceptably this way just say NO.

 

[DIYrich]

Specifically there was some bitching about this overloading the ring circuit. However these same people were very defensive when it came to overloading an RCD and attached cabled with more current than they were rated at. Mine has 3x32A circuits via a 63A RCD and cables apparently totally normal and safe as provided by the home builder and also passed via an official test report.

My guess is that the concern relates to having more than one current providing devices on the same ring - inverter and grid. You have to ensure that both devices do not overload the ring when providing max power. Similar to the USA where solar is fed into the main panel that is also fed by the grid. The grid breaker plus the inverter breaker can't exceed 120% the rating of the panel. In order to increase the solar, the grid breaker is reduced, or derated.

 

[fourtytwo]

If I was going 'to do what I like' I wouldn't waste my time here would I. I would just get on with it because job can be done safely and in a cost effective way with much less effort than this. This is about getting it done in an approved way and signed off with Part P / BC if required. If you know it can't be done acceptably this way just say NO.

Well it's just a bit more complicated than you implied, definitely it's a NO on an existing ring circuit. An excerpt from G83 that I believe still applies and what I had to comply to reads "
An inverter supplied from a PV array must preferably be installed in a
dedicated circuit in which:

• no current-using equipment is connected, and
• no provision is made for the connection of current-using equipment,
• and
• no socket-outlets are permitted.

It then goes on to specify the type of cable, protection equipment etc. Another requirement is that the voltage drop should not exceed 1% etc etc
So you either need someone who knows the current regs or somehow obtain a copy yourself however as is often the case these can be expensive and copyright protected.
On the point of Sparkies certifying DIY installation work for part P I think you will have a very tough time finding one prepared to do it but good luck if you do
I am not anti DIY but just be careful that you don't invalidate your insurance.