How to tell main fuse size

[Stephen Hall]

I am getting an EV so having a charger installed, this needs a 80 or preferably 100A main fuse. I looked at the main fuse and saw 60A but looking again it is a 60/80A holder, is there a way to tell what size of fuse is fitted without pulling it?. The house is a 70's model although we did have a new consumer unit fitted a while back. The holder is a black Henley 60/80A 415V B.S.88:1967 picture link (hopefully) below

https://imgur.com/CLY7x6Q

 

[Murdoch]

I would suggest it's a 60a

What is your heating and cooker fuel?

 

[SPECIAL LOCATION]

we did have a new consumer unit fitted a while back.

New CU fitted...

Do you have the paperwork..?

When changing a CU a whole bunch of test should be done and results written on a document called an "electrical installation certificate"..

The supply characteristics and max demand of the installation should be written on this certificate.

Other than that or enquiring from the DNO..

you have no legal rights to open the supply cut-out as it is not your property.

But..  

the electrician fitting the charger will be checking this out, as its not a DIY task anyway.

:coffee

 

[kerching]

Also do you have any electric showers?

if so, what size?

 

[boltonsparky]

The only way to know for sure is pulling it and opening the holder, the only people who should do this are the DNO.

If it's a 60a there are chargers out there with CT clamps that monitor the current and reduce the charge to the vehicle accordingly to prevent overload of the fuse and can avoid the need for a potentially costly supply upgrade. Schedule your charge for overnight when unless you're on economy 7 your demand will most likely be very low and there'll be no need for the charger to throttle back on the charge it's feeding the EV.

 

[Stephen Hall]

in the past we had an electric shower which was on a 40A breaker and an immersion heater, but not currently. The consumer unit has a 100A switch and two 80A RCD with seven breakers off each.

 

[Murdoch]

Thing is if a home has gas heating, and no electric showers or hot tubs then an EV charger isn’t a problem - even with a 60A fuse

 

[SPECIAL LOCATION]

New CU fitted...

Do you have the paperwork..?

As per early question....

What does the electrical certificate from the CU change say???

:C

 

[NozSpark]

As @boltonsparky says..... get your installer to install an EV charge point with load curtailment built in... with a 60A main fuse the limit should be set to 55A. But this should be ascertained when they do their site survey... if you're just making an online enquiry with them, through something like EVcomply, then just fill the form in to the best of your knowledge and take the required photos