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[dave the builder]

I've replaced a 60 Amp cut out that had shat it's black tar guts out 
they will happily sit glowing at double capacity for hours
cable in the street if a 1970's house is probably more tolerant than a 1930's paper wrapped cable ,which I'm sure the grid still has plenty of 

[Kevin Wood]

It's not really about the fuse in the incomer, though. A 70's delivery network was probably designed with an overnight diversity of between 1 and 2 kw per house, and the fact they were fitting 60A fuses might indicate that it has got worse than that since. That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

[dave the builder]

More work for builders when all the houses burn down 

[TheBoy]

That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

But that's when solar renewables are at their most efficient.  Oh, hang on a sec, they haven't thought that one through too well...

[Kevin Wood]

That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

But that's when solar renewables are at their most efficient.  Oh, hang on a sec, they haven't thought that one through too well...

So, we're all going to end up working night shifts and, in other news, eating tofu?

[Migv6 le Frog Fan]

Reading between the line, it seems the outage which affected half the country on Friday may have been due to the experts thinking they could rely on wind power when they couldn't ?  If this was the case, I imagine it unlikely that they will ever admit it. 

[Viral_Jim]

It's not really about the fuse in the incomer, though. A 70's delivery network was probably designed with an overnight diversity of between 1 and 2 kw per house, and the fact they were fitting 60A fuses might indicate that it has got worse than that since. That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

Electrics aren't my strong suit, I can wire a plug, know how to run cables to keep building control happy, but diversity loses me a bit.

Kevin, can you explain why you would have night time diversity that's different from peak, say when everyone turns on their oven, shower or kettle, which 80% of people do at the same time. 

Even if I get a 7kw wall box put in, that's still pulling less than when I have a shower, (9kw) or more to the point at 645am when loads of people put the shower on.

[ronnyd]

As I previously said many times, the national grid is dangerously close to capacity ,and antiquated  ....

You sure? How will we recharge our electric cars then? 

you tell me 
batteries from pound land 

or we need to spend billions updating the grid ,which will cause massive disruption and cost billions

The DNO's have been downgrading 100 amp cut outs to 60 amps for many years
check what yours is if it's labeled ,obviously take care,just a visual inspection
no removing seals or wiggling the DNO's cables (which may be loose if you had a smart meter installed by some ex Tesco shelf stacker , who's only had a few weeks training )

Err, wots a DNO Dave? 

[dave the builder]

Distribution Network Operator
 eg, western power
people who do the big wires 

[Kevin Wood]

It's not really about the fuse in the incomer, though. A 70's delivery network was probably designed with an overnight diversity of between 1 and 2 kw per house, and the fact they were fitting 60A fuses might indicate that it has got worse than that since. That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

Electrics aren't my strong suit, I can wire a plug, know how to run cables to keep building control happy, but diversity loses me a bit.

Kevin, can you explain why you would have night time diversity that's different from peak, say when everyone turns on their oven, shower or kettle, which 80% of people do at the same time. 

Even if I get a 7kw wall box put in, that's still pulling less than when I have a shower, (9kw) or more to the point at 645am when loads of people put the shower on.

Essentially, they size the network and the substation that feeds it based on an assumption of what the average consumption of a house will be at various times of the day, knowing that it will be many times higher for relatively short periods of time during the day. Not everybody takes a shower at the same time, so a 9kw draw for a few minutes at a time doesn't cause a problem where there are other houses drawing very little energy. Over a development of a few hundred houses it all averages out to a reasonable current draw from the substation so everything can be rated for very little current in comparison to the maximum that each household could consume multiplied by the number of households. This reduction from the theoretical maximum current rating required (which is impractical) is called diversity.

The network can withstand short periods of substantial overload such as when sunday roasts are in the oven or when a popular TV programme ends and everyone puts the kettle on. This is fine as long as the network gets some time to recover, which is where the likely night time loading comes in. For a housing estate with gas central heating fitted, this can be very low. A few hours of light loading allows substations and underground cables to cool off (they are large items with considerable thermal inertia). The sizing of the infrastructure relies on this period and so a big change to the pattern of night time consumption across many homes would invalidate the diversity calculations and cause the local network to need to be resized if it is to remain reliable. A switch to charging electric cars at night is exactly the sort of change that would cause this.

[STEMO]

It's not really about the fuse in the incomer, though. A 70's delivery network was probably designed with an overnight diversity of between 1 and 2 kw per house, and the fact they were fitting 60A fuses might indicate that it has got worse than that since. That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

Electrics aren't my strong suit, I can wire a plug, know how to run cables to keep building control happy, but diversity loses me a bit.

Kevin, can you explain why you would have night time diversity that's different from peak, say when everyone turns on their oven, shower or kettle, which 80% of people do at the same time. 

Even if I get a 7kw wall box put in, that's still pulling less than when I have a shower, (9kw) or more to the point at 645am when loads of people put the shower on.

I found this for you, Jimmy. Happy reading 

http://www.demand.ac.uk/wp-content/uploads/2016/03/DEMAND2016_Full_paper_158-Durand-Daubin.pdf

[TheBoy]

The network can withstand short periods of substantial overload such as when sunday roasts are in the oven or when a popular TV programme ends and everyone puts the kettle on. This is fine as long as the network gets some time to recover, which is where the likely night time loading comes in. For a housing estate with gas central heating fitted, this can be very low. A few hours of light loading allows substations and underground cables to cool off (they are large items with considerable thermal inertia). The sizing of the infrastructure relies on this period and so a big change to the pattern of night time consumption across many homes would invalidate the diversity calculations and cause the local network to need to be resized if it is to remain reliable. A switch to charging electric cars at night is exactly the sort of change that would cause this.

In addition to the time for equipment to recover, the stored energy systems also need to recharge (in most cases, pump the water back to the top lake) before the next time there is a peak in demand.

[Rods2]

That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

But that's when solar renewables are at their most efficient.  Oh, hang on a sec, they haven't thought that one through too well...

At least the windmills will make up for that for night charging, where wind is solar driven there is generally less of it at night & during the winter when you get peak demand, especially when we have an exceptionally cold high pressure area over the UK for a few weeks. Last winter over a 6 week period they were only generating at an average of 13% of peak capacity with their bird slaughterers. Doh. Will the phrase "In the Doldrums" apply to electric cars when your becalmed from not being able to charge it for a few weeks?

[Rods2]

It's not really about the fuse in the incomer, though. A 70's delivery network was probably designed with an overnight diversity of between 1 and 2 kw per house, and the fact they were fitting 60A fuses might indicate that it has got worse than that since. That'll all be absolutely fine when everyone's got a milk float on charge overnight, of course.

Electrics aren't my strong suit, I can wire a plug, know how to run cables to keep building control happy, but diversity loses me a bit.

Kevin, can you explain why you would have night time diversity that's different from peak, say when everyone turns on their oven, shower or kettle, which 80% of people do at the same time. 

Even if I get a 7kw wall box put in, that's still pulling less than when I have a shower, (9kw) or more to the point at 645am when loads of people put the shower on.

Essentially, they size the network and the substation that feeds it based on an assumption of what the average consumption of a house will be at various times of the day, knowing that it will be many times higher for relatively short periods of time during the day. Not everybody takes a shower at the same time, so a 9kw draw for a few minutes at a time doesn't cause a problem where there are other houses drawing very little energy. Over a development of a few hundred houses it all averages out to a reasonable current draw from the substation so everything can be rated for very little current in comparison to the maximum that each household could consume multiplied by the number of households. This reduction from the theoretical maximum current rating required (which is impractical) is called diversity.

The network can withstand short periods of substantial overload such as when sunday roasts are in the oven or when a popular TV programme ends and everyone puts the kettle on. This is fine as long as the network gets some time to recover, which is where the likely night time loading comes in. For a housing estate with gas central heating fitted, this can be very low. A few hours of light loading allows substations and underground cables to cool off (they are large items with considerable thermal inertia). The sizing of the infrastructure relies on this period and so a big change to the pattern of night time consumption across many homes would invalidate the diversity calculations and cause the local network to need to be resized if it is to remain reliable. A switch to charging electric cars at night is exactly the sort of change that would cause this.

Where I live the underground cable joints are gradually failing leading to a prolonged power cut if your on the same phase as the faulty joint, where they have to dig up the road & replace it. Much higher peak loadings & bigger temperature cycles aren't going to improve this reliability.

[Kevin Wood]

Speaking of milk floats, I had a ride in a colleague's I3 today.

I have to say, with 4 big blokes shoe-horned into it, it was pretty nippy around town. We did have to be shoe-horned in, mind.

It's clear that weight saving has the main objective of the design. Most of the interior seems to be made from papier mache.

I won't be swapping the little blue pussy for one any time soon.