An 80A supply is now a 100A supply- discuss

[baldelectrician]

Got an EV (Nissan Townstar EV) in my house, has a Zappi EV charger installed (by myself) and notified via ENA form to Scottish Power energy networks

Now at the outset my house is older and they could not identify the cable size and cut out fuse size

During the intial call I was told that SPEN would provide a 100A service and upgrade my supply to a 100A service for free if needed, anything over 100A would require me to pay for the upgrade

A SPEN contractor changed my cable head and verified my lead PILC cable could not be uprated to 100A, they left me with a new cut out and an 80A fuse

I pressed them and asked them to upgrade the cable to a 100A supply and this was the response I got:

Hi Stewart,

Just to reiterate what I mentioned in my previous email

The fuse you currently have (80A) can provide over 100A for decades without degrading. We would only give 100A if your supply was 35mm Al for instance.

So as mentioned, should your demand exceed the 100A supply provided you will need to go through the getting connected process and arrange for a new supply.

I hope that makes sense, feel free to call to discuss your options further. For now I will close this enquiry as we have carried out the modernisation that we can.

Kind Regards,


So, now an 80A supply is deemed a 100A supply when they feel like it.

 

[pc1966]

I guess this is what is called "sweating your assets".

 

[Avo Mk8]

Maybe there is some logic behind this:
If S P Energy Networks know the PILC cable is capable of handling 100A, but not much more.
They could have a policy of refusing to put a 100A fuse in the head, because 100A fuse will only blow after the continuous load gets past 150A, ie past a safe current for the cable.
However a 80A fuse will blow if the continuous load exceeds around 120A, which might be survivable for the cable.
At 100A the 80A fuse will survive indefinitely, as they say.

So you seem to have 'permission' for up to 100A demand - where's the problem?

 

[baldelectrician]

Got an update on this

Went through the complaint process with SPEN and they agreed to upgrade the supply (for free) as I intend to do more green stuff in the house and could not with the current supply

I now have a 3 phase 80A supply at my home and 2 consumer units

One a single phase unit with about 9 circuits for essential power which has a double pole Hager changeover switch
The second is a 3 phase Hager DB which does the whole house and also supplies the esential power DB

I intend to get a Givenergy All in one as well as 13kW of battery storage once the money builds up.

 

[mhar]

Locally most supplies are 80A.
The stated reason is that the supply agreement is for 15kVA and an 80A fuse is the nearest to this, a 60A being under the 15kVA the agreement states they must supply.
However it is dno policy to change any 100A fuses for 80A as there have been instances of the fuse carriers melting on sustained overload. The fuse carriers (and the cutouts) are rated for 100A but can be subjected to considerably more than this as Avo Mk8 states with a 100A fuse in situ. Less so with an 80A as Avo states.
Similar reason for de-looping. With the cutout terminals rated to 100A it was pretty unlikely that this rating would be exceeded taking diversity into account. However with the heavier loads from EV charge points etc they are unable to rely on this diversity and have to de-loop

Maybe there is some logic behind this:
If S P Energy Networks know the PILC cable is capable of handling 100A, but not much more.
They could have a policy of refusing to put a 100A fuse in the head, because 100A fuse will only blow after the continuous load gets past 150A, ie past a safe current for the cable.
However a 80A fuse will blow if the continuous load exceeds around 120A, which might be survivable for the cable.
At 100A the 80A fuse will survive indefinitely, as they say.

So you seem to have 'permission' for up to 100A demand - where's the problem?