Meter tails and 100A main fuse

[CRAIGNEWHAM]

Morning,

Ive just changed a CU and the existing meter tails were 16mm. I have put new ones on that are 25mm, and connected these to the 16mm from the meter in a henley block. The flat has a 100A main fuse. I am going to use this as one of my locations for my NIC assesment. Should I ask the supplier (British gas) to come and change the meter tails from the meter to the henley block? do they normally charge for this?
Are distributers not non-conforming every time they put a 100A fuse in with less than 25mm tails?
I know its highly unlikely that this will ever be a problem, but I just want to make sure I do everything right.
There must be lots of domestic properties that have 100A fuses and dont have 25mm tails?
Thanks for any help
Craig

 

[malcolmsanford]

I know from experience that the DNO are quite good on tails, where as the meter fitters will fit to a bit of VIR 7/029 as they have no idea what it is.

Are you sure it is 16mm the old tails from the meter to the Henley block, some of the old non double insulated imperial cabling such as the 19/044 which is about 20mm and the 19/054 which was 25mm does look small. It would do no harm to call the DNO and have a chat with them, if they had fitted that 100amp fuse and the tails are indeed 16mm they will change them

 

[IQ Electrical]

Morning,

Ive just changed a CU and the existing meter tails were 16mm. I have put new ones on that are 25mm, and connected these to the 16mm from the meter in a henley block. The flat has a 100A main fuse. I am going to use this as one of my locations for my NIC assesment. Should I ask the supplier (British gas) to come and change the meter tails from the meter to the henley block? do they normally charge for this?
Are distributers not non-conforming every time they put a 100A fuse in with less than 25mm tails?
I know its highly unlikely that this will ever be a problem, but I just want to make sure I do everything right.
There must be lots of domestic properties that have 100A fuses and dont have 25mm tails?
Thanks for any help
Craig

The DNO/suppliers do not work to BS7671:2008 on their side of the installation.

The 'tails' belong to the consumer and will have been installed by the consumers installer.

If the seal is 'missing' from the suppliers fuse, a connection could be made straight to the meter without a henley block

 

[CRAIGNEWHAM]

Thanks Malcolm. Ive spoke to central networks and they dont seem to know much without sending people out!
I would have thought they would have all this info on a database.
I'll ask them again, but they are hard work! isnt it the supplier who would have to come out as its the connections at the meter?
Thanks IQ
The meter was changed not long ago, and I dont want to touch the meter without speaking to the DNO/supplier first. Even if they disconnect the meter so I can change them myself

 

[IQ Electrical]

Thanks Malcolm. Ive spoke to central networks and they dont seem to know much without sending people out!
I would have thought they would have all this info on a database.
I'll ask them again, but they are hard work! isnt it the supplier who would have to come out as its the connections at the meter?
Thanks IQ
The meter was changed not long ago, and I dont want to touch the meter without speaking to the DNO/supplier first. Even if they disconnect the meter so I can change them myself

Once you call a supplier, unless you have a dangerous situation, be prepared for a frustrating time-no information, no known procedures and passed from person to person, it's pretty pathetic and never seems to change.

I have it on very good authority that the DNO's are about to be 'forced' into allowing a competent person to withdraw a supply fuse as a compromise brought about by the impending mass installation of smart metering.

 

[malcolmsanford]

No IQ is quite right, what i meant was that becasue it is the meter you would need to contact the DNO as you said, it's one thing hoping a fuse might fall out, it's another thing entirely changing tails from that meter.

You will need contact as you say the DNO/ electricity suppier to arrange changing those tails yourself. But I still would look at the chance of though it being a new meter, are the old tails imperial and single insulated, and therefore rated to the load protection device.

 

[malcolmsanford]

Once you call a supplier, unless you have a dangerous situation, be prepared for a frustrating time-no information, no known procedures and passed from person to person, it's pretty pathetic and never seems to change.

I have it on very good authority that the DNO's are about to be 'forced' into allowing a competent person to withdraw a supply fuse as a compromise brought about by the impending mass installation of smart metering.

A supply fuse yes mate, but what is there attitude towards opening a meter cover? It would be a real about turn if they allowed that.

 

[MarkP]

From a suppliers point of view 16mm tails the meter are fine. When meters are changed nowadays the main fuse is downgraded to 80amp or 60amp for 16mm tails going through an external wall.

I got called to a job a few weeks ago and was asked by a sparky on site to upgrade the tails on a single phase supply to 25mm from 16mm. After explaining to him that we work to different regs he accepted what I was saying. On leaving site I get a phone call saying the sparky has rung up and complained that I haven't changed the tails!! Can't help some people.

 

[IQ Electrical]

A supply fuse yes mate, but what is there attitude towards opening a meter cover? It would be a real about turn if they allowed that.

There was no mention of the actual meter, only withdrawl and subsequent insertion of the supply fuse.

The problem (for the DNO's) is that if you're moving/bending/cutting 25mm insulated & sheathed meter tails to accomodate smart meter installation, how do you ensure compliance with 526.1 within the consumers distribution board etc?

We all know what it's like getting a good, tight connection at the main switch in a consumer unit/distribution board without someone coming along later and putting mechanical stress/strain on those cables.

So, the DNO would have to access the consumers installation following installation of the meter to ensure compliance with 526.1.

At the moment, they have no right to access the consumers installation, in the same way that we have no right to withdraw/insert the supply fuse

 

[CRAIGNEWHAM]

Thanks Mark P - I have checked the fuse and it is a 100A. How come they can work to 16mm for 100A??
And those go from the meter to the henley block anyway?

Thanks IQ, Malcolm
Should I ask the DNO to change the fuse to a 60A??
They look like 16mm Malcolm, is there another way of telling 'physically' while I try and get answers from Central Networks?

 

[MarkP]

We use to put a 100amp fuse in but that changed some years ago. New supplies all get 80amp now (unless it's 60amp as stated above) and so does any other supply when we change a meter in our area.

The property you're working at probably hasn't had the meter changed for sometime, although saying that some Meter Operators don't change the fuse anyway!

I'd leave the 100amp fuse in. I've never had a call out where the sparky or home owner wants the main fuse changing just because of a CU change, plus I imagine you'd get billed for it.

As long as you've connected your 25mm tails from the henley blocks up to the CU I can't see you having any problem on your assessment even if the metering has 16mm's in to the henleys.

 

[CRAIGNEWHAM]

Mark P - the meter was only changed about 3 weeks ago. But they left the 100A fuse in.
"As long as you've connected your 25mm tails from the henley blocks up to the CU I can't see you having any problem on your assessment even if the metering has 16mm's in to the henleys"
- would the inspector not have expected me to request the supplier to uprage (or allow me to) the tails from the meter to the henley block though?
Thanks

 

[MarkP]

I wouldn't of thought so. As I said earlier, we work to the supply regs not BS 7671.

Plus if you've connected from the Henley blocks to the CU it proves you haven't interferred with the metering supply side of things. Do they ask you about safe isolation on these assessments?

 

[CRAIGNEWHAM]

They are very keen on safe isolation etc!
Where do the supply regs end? the supply side of the meter?

 

[MarkP]

The outgoing tails are normally the responsibility of the customer, however in this case with the henley blocks been in place I imagine you'll be fine.

What you could do is just ring the customers supplier and ask for a 100amp isolator to be fitted in place of the henley blocks. At least this way you will be able to prove that you isolated the supply there without having to pull the DNO's main fuse. Once it's fitted just pop your 25mm tails on the outgoing side of the isolator to your new CU.