Tails

[m4tty]

When doing a cu change do you upgrade tails to 25mm regardless of main fuses size or if 60a can you leave 16mm tails in?

Cheers

 

[batty]

Generally will change them what ever size main fuse is after all new cu will be to new colours so tails technically should be too and if main fuse needs upgrading tails will be ready.

 

[Adrian]

why upgrade when 16 are fine and then just put a 2 colours sticker on the board

 

[green-hornet]

One of the main problems with any cu change, especially if its an old cutout with a 60amp supply fuse, is that the design capacity would now be out of date with the actual demand.

If you upgrade to 25mm tails and request a cutout change from the dno they will always replace with a 100amp.

Your bit done, no need for a revisit to upgrade tails at a later stage.

 

[m4tty]

thanks gh

Do they charge for putting bigger fuse in?

 

[ianmacd]

request a cutout change from the dno they will always replace with a 100amp.

Doesn't that depend on what cable they have stuck in the ground to the property and i it can take 100A?

Agree though, upgrade to 25mm.

 

[green-hornet]

Doesn't that depend on what cable they have stuck in the ground to the property and i it can take 100A? Agree though, upgrade to 25mm.

All supply cables are capable of delivering and fused by 100amp.

If you take a 3phase supply to an industrial site for instance that is built near homes you will often find that R1 is the shared phase with the houses.

I found this on a call out where a block of offices described some lighting was out but others worked and no trips had activated.

I found that a quick test accross phases showed R1 was down, along with all the houses in the road.

Most old cutouts will be changed free of charge, any fused nuetrals will be changed free of charge and any metal cutouts should be changed free of charge, these are all safety issues that the DNO's need to address.

 

[Lurch]

All supply cables are capable of delivering and fused by 100amp.

Maybe recently, but that hasn't always been the case. There are definitely properties out there that couldn;t have 100A reliably delivered on existing equipment.

 

[batty]

The way I see it if you are doing a cu change tails could have been in up to 90 years and probably are past there best any way so change them to 25mm job done.

 

[Theorysparky]

I requested a 100 amp upgrade a few months back and was told by the dno that it could only put in 80 amp due to their capacity at that time.

Since found out that they have upgraded the local distribution and 100 amp now available....

 

[SPECIAL LOCATION]

One of the main problems with any cu change, especially if its an old cutout with a 60amp supply fuse, is that the design capacity would now be out of date with the actual demand.If you upgrade to 25mm tails and request a cutout change from the dno they will always replace with a 100amp.Your bit done, no need for a revisit to upgrade tails at a later stage.

Some DNO's just put 80A as standard.. Quoting a max demand of 18.5Kwatts. even with 25mm tails in place.

TBH your average domestic property would be going it a bit to exceed 80A requirement.

 

[Badger]

Some DNO's just put 80A as standard.. Quoting a max demand of 18.5Kwatts. even with 25mm tails in place.TBH your average domestic property would be going it a bit to exceed 80A requirement.

except that badger and his christmas lights when they all switch on the rest of the country has a powe outage :^O :^O:^O:^O:^O:^O

 

[ianmacd]

except that badger and his christmas lights when they all switch on the rest of the country has a powe outage :^O :^O:^O:^O:^O:^O

Buy you nick the lekkie for that from your neighbours using blue artic cable so they don;t notice it in the dark .

 

[Andy™]

All supply cables are capable of delivering and fused by 100amp.

maybe the main cable in the street, but the feed from that to the house is not always - as i mentioned in SL's power failure thread the other day, i once got called to a job where smoke was coming out of the head, because the service feed was 4mm

 

[Andy™]

except that badger and his christmas lights when they all switch on the rest of the country has a powe outage :^O :^O:^O:^O:^O:^O

or Admin does one of his experiments in the shed

 

[dave2]

Thought I'd mention that the incoming cable to a new property I am wiring was solid 16mm aluminium surrounded by copper wire about 16mm in total. Seems daft that we need to put 25mm tails on the end of this.

Dave

 

[Andy™]

but thats just the way it goes

 

[revjames]

Maybe an obvious question, what happens if you go to do a CU change and the undersized tails are between the meter and CU? you cant open the meter abnd change them. Henleys? Curious because I am doing a CU change tomorrow and havent really done one for a long time (been in heavy industry most of my career).

 

[Andy™]

just as easy to fit an isolator, and then 25 from there

 

[revjames]

I don't have the juristiction to make that call. I'm given a box and told to fit it.