Meter tail size and earthing cable size on TT system

[Invisible-Man]

Hi,

1- Could anyone let me know what size should the meter tails should be on a 35mm supply on a 100amp fuse from the DNO, also the earth cable size to the earting rod? TT System!

2- Does a main double pole isolating switch exist (RCD or otherwise) where meter tails enter from meter, but on the supply side have two outlets (2 positive & 2 Neutral) rather than using a Henley block to split the tails. There is no isolator at the moment but want to run a SWA submain from a swithchfuse and thought that rather than using a Henley block to split the supply an isolator would be useful.

3- The meter states 80amp on it although it is protected via a 100amp DNO fuse, is this OK?



submain

 

[RMS]

35mm supply???

 

[RF Lighting]

What size is the supply fuse? (in amps)

I presume it is a single phase supply?

 

[Invisible-Man]

35mm supply???

Sorry, mains supply via 1x35mm overhead cable!

 

[Invisible-Man]

What size is the supply fuse? (in amps)

I presume it is a single phase supply?

100 amp supply fuse, yes single phase!

 

[JohnD]

1 - 100A fuse = 25mm tails

2 - You may be able to use this method: When a 3-phase distribution board is used for a single-phase supply, the 3 phase terminals on the main switch are connected with a purpose-made copper bridge link (this is necessary because the busbars are shaped to fit the four load-side terminals of the switch). So you use the TP-SN switch which has 4 poles even though, on the supply side, there are only two incoming cables. This is not fishy, or a bodge, it's a recognised method. This is not quite the same as you are doing, but it seems reasonable. Obviously you can use the correct enclosure for the switch.

 

[Invisible-Man]

1 - 100A fuse = 25mm tails

2 - You may be able to use this method: When a 3-phase distribution board is used for a single-phase supply, the 3 phase terminals on the main switch are connected with a purpose-made copper bridge link (this is necessary because the busbars are shaped to fit the four load-side terminals of the switch). So you use the TP-SN switch which has 4 poles even though, on the supply side, there are only two incoming cables. This is not fishy, or a bodge, it's a recognised method. This is not quite the same as you are doing, but it seems reasonable. Obviously you can use the correct enclosure for the switch.

Thanks for that, what size earth cable should I use to earth rod?