National Grid incoming supply house fuse upgrade questions

cm4ever

Hi All

With a view that in the future we may be looking at getting an EV. What are peoples experiences with the process of and the ins & outs of getting an incoming supply fuse upgrade?

Although we're fortunate in being able to live in a fairly low usage household, our existing supply fuse is only 60A. I'm expecting that this would need to be updated to probably 80A to accommodate a future EV charger - maybe even 100A depending on specific EV charging requirements...

The thing is after doing a bit of research and googling, I'm not sure of our specific options regarding requesting a possible free supply fuse upgrade. The fuse upgrade application form talks of the need to already have a newer style plastic fuse holder in place. Just looked in our meter cabinet and I'm surprised ours appears to be the older style (even though the house was built in early 2000s) - just wondering what other people in this situation were able to achieve and especially what sort of costs could be involved?

If an update to 80A is the easiest option, what sort of EV charger capability would we be restricted to and in the real world would this really be a handicap?

Please see photo for reference below: -



Thought this was probably the better fit forum to ask this question as it's more about the house electricity supply capability as opposed to specific EV/chargers.

Thanks in advance for any thoughts to help in my research and please highlight any points I haven't yet thought about.

Netexporter

I got my supply uprated to 80A. I asked for 100A, but that's what I got. I'm happy enough, as 80A is equal to the 17kW limit for a G99 export connection, so is plenty.

Work was done free, within a month of my request. They changed the whole connection head at the same time.

cm4ever

Netexporter said:

Work was done free, within a month of my request. They changed the whole connection head at the same time.

Ah right I wondered if that would still be included in a 'free' upgrade or would add a cost, thanks.

Netexporter

My DNO is National Grid (formerly WPD), so it may vary in differing regions.

Is yours an underground supply, or overhead? Sometimes they may have to limit the input, if you are on a long overhead connection.Best to ring and find out, before you make any other plans.

cm4ever

All the houses on our estate are supplied via underground cables and our DNO is Northern Powergrid.

It's just all the various charging options I'm finding are a bit hard to work out and thought I'd try and tackle the easier option of seeing what fuse upgrade could be achieved with no/minimal cost first and then work out my charging options and all that could entail from there.... 

Netexporter

The car charger will only be 7kW, for single phase, so probably doesn't need an upgrade, unless you already have several other high current devices like electric showers or a heat-pump. Als, the charger will mostly be running off-peak, so unlikely to clash with other appliances.

Perhaps, more pertinent, is whether your consumer unit and meter tails are up to the job. Looking at the photo, the tails are modern and appear to be 25mm2, so no problem there. Is there a spare "way" in your consumer unit?

cm4ever

The whole "how any EV charger would be installed" is yet another mini saga to contemplate haha especially it's external location and cable routing to get it there 

Yes I think the tails are upto the spec required for a fuse upgrade.

We also do have spare slots in our consumer unit, but don't know what the rule of thumb is these days on adding a new additional circuit or breaker to a 'plastic' consumer unit - not sure if with the newer 18th edition wiring specifications it would now require that to be changed to a metal unit instead prior to adding a new circuit.

It's all these different parts of the puzzle that need some time to think through.

Netexporter

If the CU isn't 18th Edition you'll probably require surge protection. It might be possible to fit it withing the existing CU, as there is spare room, otherwise they can fit one as a separate unit.

There's lots of electrician Youtube videos of fitting chargers and other gear, which will give you an idea of the physical realities.

This channel is quite good:

Mark The Sparky Allison - YouTube

Ectophile

I have recently had a 7.2kW charger installed on a 60A supply,  The charger has a current clamp clipped around the incoming supply.  So if I start overloading it, the charger can tell the car to reduce the charge rate for a while.

The installer added a completely new 18th Edition consumer unit for the charger and a new outside light.  I now have a collection of 16th Edition (house), 17th Edition (solar) and 18th Edition ones.

Scot_39

The DNO should check what supply your house can take before fitting a new fuse.

Some houses might also need their supply decoupled from their neighbours iirc.

Reed_Richards

I take it you will be driving long distances each day so will need to add a lot of charge to the car each night?  Or you are signing up to a tariff that only gives you a short time to charge your car?