Do tails HAVE to be upgraded?

I'm not blind, but maybe you could post the correct "maximum length" for metre tails. (After all, I only said I think the maximum is 3 metres as I was not sure.)

There is no maximum length in Bs 7671...but the DNO usually specify a maximum length without an isolator. This varies from 2.5m-5m....check with your DNO.
And it's got nothing to do with mechanical protection.
 
There is no maximum length in Bs 7671...but the DNO usually specify a maximum length without an isolator. This varies from 2.5m-5m....check with your DNO.
And it's got nothing to do with mechanical protection.

Isolator or switch fuse??
 
The amount of time this has been dragging on I could have fitted the damn switch fuse myself and moved to the next job
 
On further inspection, I found that the incoming tails are 16mm and the main earthing conductor is 6mm.

I am going to use the idea of installing a 60a switch fuse which will allow me to continue using the existing tails.

However, is 6mm not a bit small for the main earthing conductor, especially when I will bond gas and water with 10mm?

So my idea is to install a 60a switch fuse, upgrade the main earthing conductor to 10mm and leave existing tails. Then bond water and gas in 10mm. Thoughts?
 
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Depends on the installation and earthing method.

You will have to work out the necessary csa for earthing and bonding.
 
Depends on the installation and earthing method.

You will have to work out the necessary csa for earthing and bonding.

By adibiatic equation?

Those calculations always show a lot less than you would actually use.

Surely its acceptable to just upgrade main earth and bonding if 16mm tails are protected by 60a fuse
 
Those calculations always show a lot less than you would actually use.
That could be because you actually use a lot more than you actually need.

Surely its acceptable to just upgrade main earth and bonding if 16mm tails are protected by 60a fuse
A lot would agree with you but I don't follow your logic.
 
That could be because you actually use a lot more than you actually need.


A lot would agree with you but I don't follow your logic.


The reason for not wanting to replace the tails is that it will be a nightmare as the meter is in a communal hallway. Also the run is about 6 meters so will cost a fortune on cable.
 
That could be because you actually use a lot more than you actually need.


A lot would agree with you but I don't follow your logic.


The reason for not wanting to replace the tails is that it will be a nightmare as the meter is in a communal hallway. Also the run is about 6 meters so will cost a fortune on cable.

But it's not you paying? I don't think cable of that length will cost a fortune, but how big is your fortune?
 
But it's not you paying? I don't think cable of that length will cost a fortune, but how big is your fortune?

The person I'm doing it for does not want to fork out money if its not required. Times are tough.

It will cost approx £50 just for the cable.

25mm tails are £3 a meter and I need 6 metres of each + 16mm earth.
 
The person I'm doing it for does not want to fork out money if its not required. Times are tough.

It will cost approx £50 just for the cable.

25mm tails are £3 a meter and I need 6 metres of each + 16mm earth.
I'm afraid these are the type of jobs I walk away from then. If a customer doesn't want it done properly. Pay cheap, pay twice.
At £3 per metre for tails, I'd change your wholesaler, and a 100m of 16mm earth is far less than £1 per metre
 
16mm tails will happily carry 90A if ref. method C. even more if ref. F, although the osg does not quote a figure for this. if they show no signs of damage, leave 'em be. note on your cert. though that you recommend upgrading to 25mm.
 

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