Increasing Fuse Box Capacity, For Free ...

[DRD]

Doubtless like many others on here, I have been adding more and more electrical equipment to my domestic supply over the years.

My electrician was getting nervous as POTENTIALLY everything could have been on at once, and that would have taken out the incoming fuse.

The supply in my house was installed in the 1980s and was 63A. New homes generally receive 100A supplies these days.

I was mightily surprised to learn that my local electrical distribution company (Western Power) would upgrade my incoming supply to 100A free of charge. In my case it was just a matter of replacing the incoming fuse.

 

[Supersprint]

Really surprised they did this. The DNO companies are increasingly worried that the demand on the system is greater than the existing supply grid. Most of the time they won’t take the risk and would insist on a secondary supply or even upgrade to split or 3 phase. Therefore giving themselves the opportunity to charge you a shed load of cash for their work and the privilege.

 

[Cryptkeeper]

Really surprised they did this. The DNO companies are increasingly worried that the demand on the system is greater than the existing supply grid. Most of the time they won’t take the risk and would insist on a secondary supply or even upgrade to split or 3 phase. Therefore giving themselves the opportunity to charge you a shed load of cash for their work and the privilege.

Changing the fuse in the meter won't make a blind bit of difference to them.
DRD can't draw any more current than his main fuse (in the house) which is probably 63amps.

 

[DRD]

It was the main incoming fuse that was changed. My supply was previously limited to 63A by Western Power, it is now limited to 100A. Your incoming mains cables have to be able to cope with 100A. The electrician measured the cross section of mine and they were fine to carry 100A.

The Western Power electrician that did the job said that more and more older houses were going through this process and it was driven mainly by electric car charging and hot tubs !

 

[Wizcat]

Here's the link confirming that normally it's a free upgrade: https://www.ukpowernetworks.co.uk/electricity/fuse-upgrade

Makes sense, especially with more and more people getting electric cars

 

[Deleted member 2463]

I had the main fuse blow at one of the properties I rent out (electric car charger caused it we think), when the EB came round they replaced with 100amp.

My previous house and this house had 100amp already. I suspect better to get it done now than later when the Green Party have taken over the world and you can only feed your cat vegan burgers.

 

[Paul]

My electrician was getting nervous as POTENTIALLY everything could have been on at once, and that would have taken out the incoming fuse.

Interestingly I was recently looking at this.

It;s all based around OSG diversity tables. So - as an example, 6A ring/fuse for Lighting... Do those lights realistically use 6A? In most cases, no... lets say 10 60W bulbs... 600w - therefore circa 3A max.

From 17th Edition....

The DNO's use a fairly simple calculation that is called the estimation method for determining the size of cable and protective device.


The maximum demand of an installation Pmax is the sum of the loads installed Pi multiplied by the demand factor g.


Therefore Pmax = g Pi

where;


Pi is total installed load for the installation considered, being the sum of all the loads directly connected, generally on the basis of continuous duty.
g is demand factor, that is the ratio of the maximum demand of an installation to the corresponding total installed load.



The demand factor for a single dwelling is 0.4

The demand factor for a guest house is 0.6

Factorys are around 0.8


There are two ways this is done Pi can be the total of the breakers (rule of thumb, worst case scenario) or Pi can be the calculated load using the messy diversity factors outlined in the OSG.

If you look at most people's fuse boards then the sum total will add up to much larger than the incoming feed... if this is what he has looked at and made that judgement then i think they may need to head back to college

On the flip side then its a measure of common sense... it's unlikely you will switch all your machines on at exactly the same time, alongside having your Tumble dryer on Max, shower on full heat, and cooker at full blast...

 

[AlanJ]

as above. it’s never going to be an issue i have a ton of stuff on my main


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[stevebm1]

I queried this with an electrician we used years ago,ans he said that if you plugged a kettle into every switch in your house and turned them all on the same time,the main fuse would blow,but the chances of anyone actually doing that are a million to one

 

[Deleted member 2463]

Interestingly I was recently looking at this.

It;s all based around OSG diversity tables. So - as an example, 6A ring/fuse for Lighting... Do those lights realistically use 6A? In most cases, no... lets say 10 60W bulbs... 600w - therefore circa 3A max.

From 17th Edition....



If you look at most people's fuse boards then the sum total will add up to much larger than the incoming feed... if this is what he has looked at and made that judgement then i think they may need to head back to college

On the flip side then its a measure of common sense... it's unlikely you will switch all your machines on at exactly the same time, alongside having your Tumble dryer on Max, shower on full heat, and cooker at full blast...

You’ve never been to a domino arcade event then?


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[DRD]

My electrician was being conservative, but he does have a point. As my village does not have gas, we have quite a lot of potentially thirsty electrical equipment at home. I also usually overspec items. You can get 3kw or 7kw hot water geezers for example, so I got the 7kw ones. ...

Cookers
Induction hob ( these can have huge power consumption, like 11kw plus)
Storage heater
Electric/ geezer shower
Hot water geezer in workshop
Hot water geezer in pinshed
Boiler tap
....

 

[vib_ribbon]

You’ve never been to a domino arcade event then?


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have you had your smart meter installed? when your entire room is on, what's the reading on the meter?

 

[Deleted member 2463]

never actually had time to look LOL - I'll look next time. I'm guessing with the AC on and everything I'm pulling a good 10 amps...