60 AMP FUSE

[martinxxxxxx]

I changed a c/u the other day and telephoned sse and asked if they would uprate the fuse too 100A. 2 hours later they had fitted new tails (16 to 25mm),100A fuse and a new gray style fuseholder; they even fitted service blocks to split the tails between his garage cu and the house cu. All at no cost.


I guess it depends who turns up on the day.

Martin

 

[ricicle]

Most, but not all, domestic electrictricity is distrubuted by underground cables in three phase. This means that a single phase it taken by one of three houses - So effectively you will share your electrical supply with two other neighbours. The load should be 'balanced' across the phases - which means that it should be equally distributed across each phase - so that each phase carries approximately the same current.
So if you randomly start changing the fuse size of 1/3 of the three phase you have to consider the effect on the 'balance'.
In otherwords, you have to consider how to rebalance the load across the three phases - so you either increase everyones fuse and or cable size or you leave it alone.

What a load of tripe !

 

[riveralt]

Most, but not all, domestic electrictricity is distrubuted by underground cables in three phase. This means that a single phase it taken by one of three houses - So effectively you will share your electrical supply with two other neighbours. The load should be 'balanced' across the phases - which means that it should be equally distributed across each phase - so that each phase carries approximately the same current.
So if you randomly start changing the fuse size of 1/3 of the three phase you have to consider the effect on the 'balance'.
In otherwords, you have to consider how to rebalance the load across the three phases - so you either increase everyones fuse and or cable size or you leave it alone.

What a load of tripe !

If you care to explain which part is 'tripe' I will happily listen.

But I take it from your response that when you change a fuse you don't both taking into account whether the expected load will support it or whether or not the cable is of adequate size.

 

[holmslaw]

..

 

[ricicle]

If you care to explain which part is 'tripe' I will happily listen.

But I take it from your response that when you change a fuse you don't both taking into account whether the expected load will support it or whether or not the cable is of adequate size.

Of course I do for a single load, but I wouldn't uprate/downrate the corresponding other two phases just to balance load which is what your statement suggests.

 

[riveralt]

Of course I do for a single load, but I wouldn't uprate/downrate the corresponding other two phases just to balance load which is what your statement suggests.

I glad you would do that for a single load. Not sure you should be worried about balancing the other two phases though that is a matter for the DNO.

The point that was being made here is from the DNO perspective and to refute the perception that changing the main fuse is a simple job.

You still haven't given anything that explains what is 'tripe'.

Are you saying that domestic electricity is not distributed via three phase and that each phase is divided amongst three properties?
Are you saying that three phase loads do not have to be balanced?
Are you saying that the DNO does not have to consider the consequences of upgrading the main fuse in terms of the cable current carrying capacity and the possible consequences for other properties?

 

[ban-all-sheds]

He must have listened to that IET nutter who says that before adding an extra socket you should confirm if its ok with the national grid.

Or, if they aren't in, the old codger in the Electrical aisle in B&Q.

 

[ricicle]

The point that was being made here is from the DNO perspective and to refute the perception that changing the main fuse is a simple job.

You still haven't given anything that explains what is 'tripe'.

Are you saying that the DNO does not have to consider the consequences of upgrading the main fuse in terms of the cable current carrying capacity and the possible consequences for other properties?

I am fully aware of how electricity is distributed. The tripe in your post was the impression that you think the DNO, after upgrading a property's fuse, would enlarge the fuses in the corresponding other two properties on the other two phases so as to magically increase the load on those two phases as well. Is that not what you posted ?

 

[ban-all-sheds]

...each phase is divided amongst three properties?

Only 3?

What happens once you get to 9 houses on a substation then? New substation?

Are you saying that three phase loads do not have to be balanced?

I would be amazed if this were even remotely possible at the level of supplying houses from substations. There are times when our house is drawing over 50A and others in our road on other phases drawing zero. Or vice versa. There are times when people are on holiday and they don't draw any current for weeks on end.

 

[PrinceofDarkness]

Getting back to the original post by Onion: No, you don't need to have your service fuse 'upgraded' from 60A, simply for a new kitchen.

Some people are mad keen on 'upgrading' for the sake of it. If they had a 100A service they'd likely ask for more - and more........


Lucia.

 

[riveralt]

Welcome to the party BAS

...each phase is divided amongst three properties?

Only 3?
What happens once you get to 9 houses on a substation then? New substation?

Where did you get 9 houses from and sub-stations I never mentioned them.

...Are you saying that three phase loads do not have to be balanced?

I would be amazed if this were even remotely possible at the level of supplying houses from substations. There are times when our house is drawing over 50A and others in our road on other phases drawing zero. Or vice versa. There are times when people are on holiday and they don't draw any current for weeks on end.

What has that got to do with balanced loads - The capability of the load should be equally distributed across the three phases so that each phase carries approximately the same current. So I would expect to see three houses on the same leg of the three phase supply to have the same size cables and the same size main fuses. Are you saying this is incorrect?

 

[riveralt]

I am fully aware of how electricity is distributed. The tripe in your post was the impression that you think the DNO, after upgrading a property's fuse, would enlarge the fuses in the corresponding other two properties on the other two phases so as to magically increase the load on those two phases as well. Is that not what you posted ?

No I would expect the DNO to ensure that the cables were of sufficient size to exceed the rating of the main fuse, particularly if that fuse was uprated. Just like you would do on a single phase system. I would also expect to see similar sized fuses and cable sizes for each property on that leg of the supply.

 

[PrinceofDarkness]

Let's not complicate this, chaps, with theories about 3-phase balancing and other irrelevant rot. The O/P simply wants to know if he really needs to change his 60A service.

The answer is: No he doesn't.


Lucia.

 

[riveralt]

Let's not complicate this, chaps, with theories about 3-phase balancing and other irrelevant rot. The O/P simply wants to know if he really needs to change his 60A service.

The answer is: No he doesn't.


Lucia.

I bow to your better knowledge - I haven't seen the calculation for maximum demand on his circuits.

 

[ban-all-sheds]

Welcome to the party BAS

...each phase is divided amongst three properties?

Only 3?
What happens once you get to 9 houses on a substation then? New substation?

Where did you get 9 houses from and sub-stations I never mentioned them.

Does not each of the 3 phases supplying houses come from a substation then?

There are 3 phases.

If each of the 3 is divided amongst 3 properties then that's 3 x 3 = 9 properties.

So if the 3 phases from a substation are to supply more than 9 houses then at least one of them will have to be divided amongst more than 3 properties.

What has that got to do with balanced loads - The capability of the load should be equally distributed across the three phases so that each phase carries approximately the same current. So I would expect to see three houses on the same leg of the three phase supply to have the same size cables and the same size main fuses. Are you saying this is incorrect?

I'm asking how it could possibly work, as there is no way to make any 3 houses on different phases draw anything approaching the same current.

You will need to speak to your energy supplier to see if they will uprate your main fuse to 80Amps - some will - some will do it for free - some will not - some will not do it because they will have to increase the fuse size on the two neighbours who share your supply.

Even if they did that, what would be the point? Those 2 neighbours wouldn't suddenly start drawing more current to make the load on their phases a closer match to the increased load on the other one.