Home charger and main fuse

[LordSiborg]

Evening all.
So today my sparky arrives to complete the installation of my EO charger. Which he immediately says he can't do because our fuse is 60A. We're in a semi detached house, we heat with gas but we have an electric shower, electric dual oven and sometimes use the immersion heater.
He says we need a 100A fuse but the feed to the house is only 16mm. I'm assuming digging up my drive and the road outside is going to be pricey, but we should be able to go to 80A without changing to 25mm everywhere?
Simon.

 

[Tone]

You may well have to talk to your energy supplier and explain the situation.
I live in a 120 year old terest house with an old school shared electric main on the outside of the houses, and I've got a 100A main fuse.
they'll send someone out to see if you can be upgraded, or at least tell you what your options are

 

[Lovemyev]

We also have a 60 Amp protection fuse installed.
Our 7kw 32 Amp wall box was installed way back in 2015.
We had a survey done on our electrics, by the firm who was installing our wall box, prior to the install.
The house was built in 1982 and we still have the original consumer unit ( fuse box ).
We have a dual fuel cooker with a double electric oven and five gas rings.
I had been charging a PHEV for four years, then a move to full BEV with a 42 Kw battery for two years ago.
Now we have a face lift ZS EV LR and are still charging, we using a much cheaper "Off Peak" tariff.
With a 60 Amp fuse, you just need to spare a thought for what you intend to run at the same time, as charging your car !.
The 7 Kw charger is already pulling a demand of almost 32 Amps.
Your emersion heater is likely to be pulling another 3 kw's so that now takes you up to 46 Amps.
Again, your just have to think a little about the load you are placing on that fuse at any one time.
If you are running a 10 Kw shower and your emersion heater at the same time, you are hitting the absolute limit of your protection fuse at 60 Amps !.
I also have an emersion heater, but we have never used it, in favour of heating our water by our gas boiler
But now gas prices have rocketed, I have now installed a timer on my emersion heater and I am heating my water on a cheaper "Off Peak" tariff.
This is much more cost effective than heating my hot water from my gas boiler.
However, this time slot aligns with my charging schedule for charging my car !.
I am trying to slide as much of our usage into that "Off Peak" slot of 6 hours.
Having the automatic washing machine set to run within that window would also be a bonus.
So, I have contacted my DNO and requested an upgrade from a 60 Amp fuse to either a 80 or 100 Amp cartridge.
I am finding it difficult to get them to respond to my request though !.
A 100 Amp fuse is the way to go IF you intend to run a LOT of your demand at the same time !.

 

[LordSiborg]

Thanks both, I hadn't actually thought of talking to Shell, I rang UK Power Networks instead. We'll probably be moving to Octopus but waiting till our fixed rate ends.
I'm happy with the idea of staggering our usage, but sometimes the electricians want, understandably, to simply spec to the worst case scenario. I'm hoping that's what they're doing and an additional 20A will be ok. I did some calculations and if we were using everything apart from a car charger now we could easily hit 80A so there's obviously quite a lot of tolerance. The MG will pull 30A max. The immersion only needs to be on for an hour or two a day and not at all from autumn to spring, and Im sure I can avoid the charging window, although as you say it's best to put it all into the overnight window. But generally we need hot water in the early evening onwards so will have that run during the day. And we won't be having showers in the middle of the night. Well not normally!

 

[biffo]

Thanks both, I hadn't actually thought of talking to Shell, I rang UK Power Networks instead. We'll probably be moving to Octopus but waiting till our fixed rate ends.
I'm happy with the idea of staggering our usage, but sometimes the electricians want, understandably, to simply spec to the worst case scenario. I'm hoping that's what they're doing and an additional 20A will be ok. I did some calculations and if we were using everything apart from a car charger now we could easily hit 80A so there's obviously quite a lot of tolerance. The MG will pull 30A max. The immersion only needs to be on for an hour or two a day and not at all from autumn to spring, and Im sure I can avoid the charging window, although as you say it's best to put it all into the overnight window. But generally we need hot water in the early evening onwards so will have that run during the day. And we won't be having showers in the middle of the night. Well not normally!

Depending on your charger, and whether it has a CT clamp or not, some can scale back their usage to not exceed your fuse size. Not ideal if you need to charge right now, but protects main fuse if using a lot of appliances whilst the car is plugged in.

 

[Nicko]

I am about to install a Pod point solo 3 myself at my house on a 60A fuse? it does not matter with this charger. It monitors the current being drawn and will not allow the charger to exceed more than the rated fuse for the whole of the electrical installation. With this charger there is no need to advise the DNO but I will out of courtesy and it also has o-pen which means an earth rod is not required subject to the relevant test results. There are other manufacturers out there which do the same functions on their chargers. By the way I am a certified electrical engineer so there is no issues with me installing the charger. The only trouble some might have is if they are on a looped supply and it would be advised to get a professional in to assess.

 

[Les burrows]

Hi my home 1965 I think, is on a looped supply with next door, and when my Zappi charger was installed the firm that did the installation contacted the DNO who came the same day and said it was OK to go ahead with the looped supply but, if I wanted my own main cable fitted which would involve digging up my drive then they would do the work free of charge, they also checked the main fuse as it was not labelled in any way this was found to be 100amp and it’s been fine, so best advice I can give you is speak and listen to your DNO as I think they will know best
Les

 

[Ozzie1989]

Evening all.
So today my sparky arrives to complete the installation of my EO charger. Which he immediately says he can't do because our fuse is 60A. We're in a semi detached house, we heat with gas but we have an electric shower, electric dual oven and sometimes use the immersion heater.
He says we need a 100A fuse but the feed to the house is only 16mm. I'm assuming digging up my drive and the road outside is going to be pricey, but we should be able to go to 80A without changing to 25mm everywhere?
Simon.

I'm on 16mm feed and Western Power upgraded my fuse to 80a.

They offered to go to 100a but would involve digging everything up as you say, although they would have done it for free apparently. Sadly my cable runs from the back to the front of my house, underground, through 3 rooms and a driveway so decided against it.

My electrician was happy to fit my charger (Sync EV) on my original 60a fuse, however I don't have an electric shower or hob and it has built in energy monitoring. Basically they have to calculate the possible total demand, allow a bit less for the fact stuff isn't used for hours on end (like your charger) and ensure its safe before they put their name to it.

He also asked when I'd be charging, which is mainly going to be overnight on Go, so he was even happier to fit it on 60a and set the unit to ramp down at 60a. Now I had my fuse upgraded I've left it at 60a on the charger, to allow a little overhead. Mind you, to blow an 80a fuse would probably need 100a + for a good few minutes, they don't blow quickly!

I would say ring your DNO (not your energy supplier as the fuse is not their responsibility) and ask them to upgrade to 80/100a and see what they say. Then get the sparky back.

 

[Jomarkh]

Did your guy fill in a form similar to the one attached after he had done a survey for job?
If it was under the grant scheme he would have to for the grant to be paid

 

[LordSiborg]

It does have a CT clamp, I'll make sure that gets fitted anyway regardless of the fuse size. My house is 1967 but that doesn't seem to mean much!

 

[Robf]

UK Power Networks should/will upgrade for free.

 

[LordSiborg]

Did your guy fill in a form similar to the one attached after he had done a survey for job?
If it was under the grant scheme he would have to for the grant to be paid

No we are having it done as part of other building work, on reflection I should have done the research myself!

 

[Cosmic Resident]

Just like @Lovemyev , my 32A Rolec was installed in 2015, on a 60A fuse.

And I also managed to blow it.

At the time we were running a lot of appliances (washing machine, tumble dryer, oven, tv, lights, Vivarium etc.) Then after daughter had been in shower (9kW) for a couple of minutes, poof!

The DNO came out within the hour and replaced it. I asked if it was charging the car that did it, but he said no, because it takes a lot more than 60A to blow that fuse. Upon asking why it blew then, he said that they “wear out” over time.

We still have that 60A fuse, but have had no problem since.

 

[LordSiborg]

Thanks Ozzie, sounds as though if you talk to someone reasonable then you can get things done! Going to wait for the sparky to say they'll work with 80A and get the ball rolling on that basis. We won't need a second charger for a few years, hopefully it will be someone else's problem by then!!

 

[IanE]

Just to add the

Wallbox Pulsar Plus​

I had fitted you can dial down the amount of amp's it draws on the app, 32-1amp, of course it will take longer to charge your car, but it may be a solution

 

[LordSiborg]

Hi Ian
Yes my EO allows that as well, I'm hoping that just using the CT choke will suffice for now - my mileage varies wildly and I'm expecting some nights to need to charge outside of midnight-7am. At the moment I've no idea how often that's going to happen, and I won't till the 1st July when (fingers crossed) the car arrives...

 

[Lovemyev]

Depending on your charger, and whether it has a CT clamp or not, some can scale back their usage to not exceed your fuse size. Not ideal if you need to charge right now, but protects main fuse if using a lot of appliances whilst the car is plugged in.

My wall box was installed back in 2015 and is therefore a "Dumb" unit with no smart capabilities and it does not have any load management via C.T. clamps.
I have a cheap rate tariff that lasts for 6 hours.
I want to take full advantage of that time window and slide as much usage into that slot.
Charging the car and running both the emersion heater and the washing machine, will exceed the current rating of the present 60 Amp protection fuse.
A 80 Amp fuse will do the job, but a 100 Amp would be brilliant.
Upgrading our present 60 Amp to a 80 Amp is a simple switch out, because they share the same size power head.
But the 100 Amp fuse is much larger and therefore a service head replacement is required.

 

[LordSiborg]

My wall box was installed back in 2015 and is therefore a "Dumb" unit with no smart capabilities and it does not have any load management via C.T. clamps.
I have a cheap rate tariff that lasts for 6 hours.
I want to take full advantage of that time window and slide as much usage into that slot.
Charging the car and running both the emersion heater and the washing machine, will exceed the current rating of the present 60 Amp protection fuse.
A 80 Amp fuse will do the job, but a 100 Amp would be brilliant.
Upgrading our present 60 Amp to a 80 Amp is a simple switch out, because they share the same size power head.
But the 100 Amp fuse is much larger and therefore a service head replacement is required.

Plus from what UKPN told me you need 25mm cables coming into your fuse as well as everywhere on your side of it, otherwise the cable can catch fire underground. Which I'm assuming wouldn't be a good thing, just ask the residents and businesses of Holborn!

 

[Lovemyev]

Plus from what UKPN told me you need 25mm cables coming into your fuse as well as everywhere on your side of it, otherwise the cable can catch fire underground. Which I'm assuming wouldn't be a good thing, just ask the residents and businesses of Holborn!

This is totally correct, meter tails from the service head to the meter and then the consumer unit COULD require an upgraded.
My meter tails where upgraded when the wall box was installed.
Together with a 100 Amp double pole isolation switch.
This normally happens when the service head / main fuse is carried out.

 

[Hairyfool]

My DNO (UKPN) upgraded the fuse and replaced the holder (FOC) because we couldn't actually read the fuse rating, no discussion on the incomer rating so I presume it was OK. A little surprising as we are out of town and the village has quite a mixture of above ground and sub surface feeds. We had been warned that all meter tails would need to be 25mm so that had already been done as well as fitting a second CU as the main one was not in the best place. Easy to do via a Henley Block as the incomer itself was just where it was needed.

Lots of discussion on line about earthing on line so UKPN also switched us to earthing via the incomer sheath. Our existing rod metered out OK but as it appears to be underneath a garage slab inspecting it as is required was not possible. Less than happy with the sparks that had done our rewire about 5 years ago, found one of the earth wires inside the isolator for the main CU was in fact blue neutral cable. He hadn't even over sleeved or taped it with green/yellow.

Scottish Power contractor more than happy. Less than a metre from the CU and a hole through the wall ready for him as I had fitted a 16A connector for the motor home.