How much rewiring each side of meter on fuse upgrade 60 to 100

[pgtips]

Hi,

Our bungalow has 60a, will need upgrading to 100 which UK Power networks will do FOC.

I have what I measure to be 10mm cable in and out of the meter into fuse board.

For anyone who may have experienced (or even had done) the upgrade my Q is, do they (UKP) upgrade to the meter only or also meter into the FuseBoard. ? I ask becuase I read that for 100A then 16mm would be the size cable but, currently coming out of the meter is only 10mm.

Its been 60A/10mm for ever so the world won't stop if they don't but I'd like to plan ahead a bit if I need to get an electrician in or not.

We've got overhead cables into the property so not too bad to do but out of interest how on earth do they do it if your cables run underground, I imagine its a right PITA.

Thank you as always for the helpful replies

PG

 

[EFLImpudence]

No, they won't do to the 'FB' - and

you will need 25mm² for 100A.

 

[Taylortwocities]

I have what I measure to be 10mm cable in and out of the meter into fuse board.

How did you measure that? The size of a cable is the cross sectional area of the copper conductor, not the outside diameter of the cable itself. this varies slightly between makers.

This document https://www.elandcables.com/media/3lldq1ep/6181b-cable.pdf
shows that the outside diameter measurement of 25mm² meter tails is 9.7mm. so, if you are measuring 10mm its a good bet that your meter tails are already 25mm² and nothing needs to be done.

 

[pgtips]

Thank you @Taylortwocities , good to know.

I measured the outside of the cable using a Vernier guage so it is like you say, most likely already 25mm2 which is reassuring.

 

[flameport]

Our bungalow has 60a, will need upgrading to 100

Who 'needs' this upgrade and why?

out of interest how on earth do they do it if your cables run underground, I imagine its a right PITA.

Dig up the road and sections of the driveway, front garden and whatever else is in the way.
Or just change the fuse.
Depends on what cable is already there,

 

[SUNRAY]

Who 'needs' this upgrade and why?


Dig up the road and sections of the driveway, front garden and whatever else is in the way.
Or just change the fuse.
Depends on what cable is already there,

Our street is supplied by a 0.25" PILC, the houses & bungalows are 0.0225" PILC branches looped to 2 properties, in my case also a 0.0044" PILC to a lamp standard (the sizes are from memory from maybe 10 years ago for a neighbours building works so apologies if not accurate, I'm assuming those equate to 160mm², 15mm² & 2.8mm²) 30 or 40A fuse for 2 or 3 bed bungalows and 60A for houses was the standard.
When EV chargers are being installed; DNO generally digs where the feed and loop are close together and makes the Tee there rather than within a cut-out to allow for a bigger fuse.
However I know elsewhere EV chargers are being fitted on looped supplies and I even know of one situation where 3EV chargers have been installed on a looped supply where the Tee remains in the cut-out. However that is a PVC feed and I know not if that makes a difference. https://www.diynot.com/diy/threads/self-install-ev-charger.582413/#post-5109782 post#11

 

[pgtips]

Who 'needs' this upgrade and why?

Who.. is me.

I calculate I need this upgrade. Admittedly most of my electrics background is automotive and recently lithium LBs (where it works a bit differently, you only have a finite number of amps to use so you have to work out what your draw Ah is for how long it'll last) but I am critically aware of the need for correct sizing of cable and fuses. Its easy now with thinwall wire to overspec the cable in a vehicle and focus to ensure fuses are correct. I've long wondered how on earth a/our 60A fuse survives and was not sleeping well thinking the cable was also weedy so an upgrade would not be straightforward to 100A.

As to the why, in its original form as a bungalow the wiring and fuse would have been more than ok but its not just a bungalow anymore, an extension garage built with scissor lift and power tools inside with bedroom above. A new kitchen with induction hob, 2x under sink water heaters to save water (I hate running taps 6+ litres just to get hot which is an angst of bungalow life, the en-suite is about 2 million miles from the boiler), they are 7.3kw and a 3kw. Instant boil kettles draw 2 to 3kw. 2 kids etc.

Rad in the garage, have gas but backup electric rads @ 2.5kw rads x3, a 9.5kw electric shower although rarely in use is there, it all started to weigh on my mind, the math just isn't right (in my opinion) just too many appliances to make 60 suitable. Shower potentially nigh on 40 amps, 10 amps for the heaters, induction hob etc etc.

For anyone coming across this post, to work out the amp draw you take the Wattage (W) and divide it by your domestic Volt supply 240V.
i.e 3kw heater = 3000/240 = 12.5Amps.

Knowing that the cable is almost certainly more than capable size wise gives me huge peace of mind for a larger fuse and there seems no reason not to. Who knows about the future and whether or not I'll get an EV but either way ready if needed.

Filling out the Nat Power network form with a few simple Qs tells me they'll fit a 100A. I am really glad I asked on the forum for the extra information/peace of mind about the cable so thanks to all .

PG

 

[EFLImpudence]

Admittedly most of my electrics background is automotive and recently lithium LBs

Then I am puzzled that you did not know how electric cable is sized.

I've long wondered how on earth a/our 60A fuse survives and was not sleeping well thinking the cable was also weedy.

10mm² is adequate for 60A supply.

 

[endecotp]

there seems no reason not to.

Apart from the cost.

 

[JohnW2]

Apart from the cost.

Our bungalow has 60a, will need upgrading to 100 which UK Power networks will do FOC.

 

[briwire]

Measuring the outside diameter of the cable could be misleading as different grades of cable have differing thicknesses. Tri-rated for example. It may be close enough to give a 90% estimation. But the only true way would be to measure the diameter of a strand of the cable, divide it by two to give its radius. Then use the calculation Pi x r squared, so 3.142 x r x r. This will give the cross sectional area of each strand. Multiply that by the number of strands and it should be close to one of the sizes, 10mm, 16mm, 25mm for example.

 

[JohnW2]

.... the only true way would be to measure the diameter of a strand of the cable, divide it by two to give its radius. Then use the calculation Pi x r squared, so 3.142 x r x r. This will give the cross sectional area of each strand. Multiply that by the number of strands and it should be close to one of the sizes, 10mm, 16mm, 25mm for example.

True, but rather difficult when (as in the OP's case) the cable in question is in service

If the cable is remotely 'modern', it ought to have an indication of its 'size' (CSA) printed on it.