@transparent Sometimes I feel I am thinking myself into a hole in the ground (Jim Henson, Storyteller).

The incoming cable is marked OF 462-467, I can see no other marks.

My High current devices are 32A socket for my Home brew set up used very intermittently though maybe for several hours but when not used I plug in a 4mm2 swa lead to my car charger which runs at 13A. I do not feel a 7KW  charger at cost of over £1,000 makes sense currently.

The intention is to fit a 6KW Daikin. 

Two SWA cables suppying garage and shed on the RCD side of the CU.

I would really like to replace the CU fitted with RCBO which could leave some free ways (there is one on the non RCD side at the moment.

On my contract Octopus say DNO service upgrade required which they take care of.

Perhaps I can I pm you my address later?

The incomer cable probably only has a size-rating once every meter.
The OF 462-467 doesn't give me enough information without also knowing the cable manufacturer.

But it will be identified on NGEDs EMU mapping tool.
Yes, send me the address by PM whenever you're ready.

I too don't have a "charger" for my EV.

I've installed a 6mm² cable to an external 32A socket.
That means I haven't yet used any government subsidy for a Smart Charger,
but could do so later if one emerges which can offer V2G or V2H for a CSS connector.

New / replacement consumer unit:

The present regulations stipulate the need for three levels of 'protection' for each circuit:

• over-current (MCB), which is calculated according to the cable size and constraints
• earth leakage (RCD & RCBO) 30mA max difference between live & neutral to prevent fire and injury to people
• arc-detection (AFDD) to cut out if there's a loose terminal or rodent damage

All three levels of protection are available in a single-module wide device, but are expensive:

Those prices are from the electrical wholesaler TLC-Direct, and exclude VAT.

In most domestic properties, AFDD is not yet mandatory.
But you should ask your electrician whether any of your circuits do fall into the higher-risk category which requires them.

I've used separate RCBOs on all power-circuits,
and a single RCD to protect all four mains lighting circuits.

That might seem odd, in that a fault on one lighting circuit would plunge the entire house into blackout(!)

but in practice it no longer matters because half of my lighting is now operating on 24v DC, derived from the storage battery.
That means we have light during a power cut.

I have changed my mind on the arrangement of trips over the years,
and I'm about to replace one more of the RCBOs with a bi-directional type.

So please feel free to challenge what I've written and ask me to justify my choices!

A Daikin Altherma-3 (6kW) ASHP requires a 20A trip/fuse to supply it.
That excludes the 12A which is required for a 3kW DHW immersion heater if Octopus install one.

Update:

@jancold and I have been discussing the details of the electricity supply to their house.

I can't post the cable maps here because they contain information about other houses in the locality.

The area is served by two local substations, with cables that cross over.
There are many situations where semi-detached and terraced houses (joined to each other) are supplied from different substations!

There are also many looped supplies:

What started as a matter of installing

• a Smart Meter
• a heat-pump

has turned into a situation where the DNO is likely to want other changes.

That's fine.

There will be many properties in Britain which require grid upgrades and re-routing of cables as we progress towards Net Zero.

We can't yet be certain of the supply cable size to Jancold's house, but most in the area are (only) 16mm².
Normally that would be terminated with a 60A Service Fuse.

It's the responsibility of the DNO to assess the voltage drop along the cable route from the substation and decide whether this needs replacing with 25mm² in order to support the use of a heat-pump.

This gets more interesting/ baffling. It appears the supply was reversed some time ago. There is no connection to the care home pole now. The cable supplying my house looks pretty small. With supply drops to each property does that make it a looped supply?

Yes, those are excellent examples of looped supplies 😎 

I'm labeling your house B in the photo, which has the camera pointing East.

The NGED mapping tool shows House A supplied from a pole in the road on the other side of the house,
and your house B looped from House C, which is off the photo to the left (north west from you).

It's the supply to House C which is shown on the DNO map as coming from a pole in the grounds of the care home behind you.

Either way, your house is looped.
And that's what NGED will want to change.

They will de-loop you from House A and/or House C.

That gives them two main options of how to give you a new supply cable of your own.

My preference (without having the cable voltage-drops to view) would be to connect you to the pole at the front of the house.

Why?
... because that has 3-phase available on it.

That keeps further options open to NGED, depending on which other houses install high current loads in future (which they will).

Is a heat pump using a few kW continuously considered to be a more onerous design condition than an electric shower which could use 9kW but for only a few minutes?

Good question.

This is one of those situations where the DNO considers not just the current being drawn, but the time over which it is active.

Low Carbon Technology (LCT) requires consent from the DNO, in just the same way as you get permission to export to the grid from an inverter.

LCT is currently defined as:

• Heat pump
• EV charger

I think storage batteries should be there too,
but I don't make the rules.

Most houses are supplied by one of -

• 16mm² cable; rated 73A, usually fused at 60A
• 25mm² cable, rated 101A, fused originally at 100A, but now being fused at 80A

If a house draws more current than the fuse rating for several minutes, then the fuse and cable get warm, but the power keeps flowing.
So an electric shower which takes the total current above 100A isn't likely to blow the Service Fuse.

But heat-pumps and EV Chargers will be drawing current continuously over 4+ hours.

@transparent So does the NGED need to do this Upgrade before the Heat pump and smart meter install? The meter is mid January and the Pump late March.

NGED need to start their work first.

Until you know whether you will be supplied with single-phase or 3-phase, Octopus can't know which Smart Meter you require.

NGED are super-efficient, but their best of intentions can be thwarted by emergency repairs (storm damage etc).

Although Octopus are meant to arranging everything, we don't know if their surveyor noticed that the house had a looped supply.

You could always fill out your own online Application form for LCT connection, which is free.
That would allow you to receive direct communication with the Network Team for area 1328.

We already know that the system should decline your application of course.
So you can ignore the advice which says you'll receive approval within 15-mins!

The important bit is to get a job-reference and open communications with the Area Team.

Ask again here if you need help with the application.
And if there's a space to add any further information, tell them:

This looks like a looped supply: See online discussion on Renewable Heating Hub Forum:
https://renewableheatinghub.co.uk/forums/electricity-providers/smart-metre-installation-seamless-or-a-potential-nightmare/paged/10#post-38551

because that's the link to your first post about this issue.

@transparent So good so far I have completed the form and got my reference.

So this is their reply.

"I have identified that a Removal of a Looped Service is required and potentially a Cut Out Change.
This may require some excavation work to be carried out on your, and where necessary, your
neighbours property (subject to their permission). These works are required to ensure that you can
continue to utilise your installation.
We will contact you in due course to make arrangements to complete works, which will be carried out
free of charge."

Next I need to tell them about the Heat Pump, Oh and the link to this thread. Do you have any further a advice regarding my next communication with them?

Yes, they need to know about the Smart Meter proposal as well as the heat-pump installation.

I think the mention of excavation is taken from a 'standard response'.
The potential supplies to your house from either of the two local sub-stations are overhead cabling.

It's true that the majority of properties fed from transformer 31/1163 are underground, but the feed in your particular road is Aerial Bundled Cabling (ABC) installed in 2012.

ABC uses Insulation Displacement Connectors (IDC) which clamp onto existing wires, piercing the outer insulation as they do so.
That makes it very easy (and quick) to add a new supply.

Yes, you absolutely should tell them about this discussion topic.

NGED have a policy of involving the public in aspects of looking after the grid, although this effort is usually directed through liaison with Councils.

DNOs revenues are constrained using the RIIO-ED2 Agreements with Ofgem.

NGED in particular have applied for adjustments to their permitted profits due to extensive proposals to enhance and reinforce LV (low voltage) connections to increase resilience.
Although this is couched in technical terminology, you can read those clauses in the appendices to the RIIO-ED2 Final Determination.

This is sometimes difficult for them to do, especially when the actual cabling doesn't match the detail on their EMU Mapping Tool.
That's what's happened in your case.

It's only because of the discussion here on the Forum, and my being granted access to NGED's in-house data that we have identified the weaknesses in the supply to you and your neighbours.

That's just the sort of public engagement which NGED are seeking in order to target upgrades at vulnerable parts of the LV grid.
However, they have to provide evidence to Ofgem that they are indeed delivering on the agreed targets.

This discussion can form part of the evidence they require.