TT stake in outbuilding

[Jase_82]

Evening. Came across a shed with armoured 2 core 2.5mm running to it on a TNCS system (RCd protected), with the sheath of the armoured being used as the earth (Shed is only 5m from house); I know this can be acceptable, but I’m adding sockets in the garden and was considering putting in an earth stake along with a new CU in the garage to split the sockets and lights etc. There is no metal pipework or roof etc in the shed.
1. Would you leave the existing earthing arrangement (which is giving current Zs of 0.6) which uses the metal sheath of the armoured cable or put in a stake which might will probably have poorer readings?
2. If you put in a stake, what size should the cable running to it be, and where do I find this in the regs?

 

[Pete999]

Evening. Came across a shed with armoured 2 core 2.5mm running to it on a TNCS system (RCd protected), with the sheath of the armoured being used as the earth (Shed is only 5m from house); I know this can be acceptable, but I’m adding sockets in the garden and was considering putting in an earth stake along with a new CU in the garage to split the sockets and lights etc. There is no metal pipework or roof etc in the shed.
1. Would you leave the existing earthing arrangement (which is giving current Zs of 0.6) which uses the metal sheath of the armoured cable or put in a stake which might will probably have poorer readings?
2. If you put in a stake, what size should the cable running to it be, and where do I find this in the regs?

Yes there would if the W/S /Shed has any metalwork that would require bonding, and the CSA of the armouring wasn't large enough to cope with earthing and any bonding that may be required. Your Electrician should realise this and advise accordingly.

 

[telectrix]

2.5mm is not really man enough to feed a CU. rip it out and replace with 6mm or 10mm. sheds suddeny become man caves, load increases in proportion to the wife's nagging. come next winter, heaters may be required.

 

[Strima]

Is this circuit from from its own MCB or a socket circuit?

 

[Jase_82]

Is this circuit from from its own MCB or a socket circuit?

It’s own 20A mcb,so I think 2.5 SWA buried direct is enough for the load requirements.

 

[Rockingit]

2.5mm is not really man enough to feed a CU. rip it out and replace with 6mm or 10mm. sheds suddeny become man caves, load increases in proportion to the wife's nagging. come next winter, heaters may be required.

My man cave has a 40A supply to it for just this reason!!

 

[telectrix]

40A is a realistic load when you consider the 1000watt hi-fi, 54" flat screen tV, smart everything, couple of 2kW heaters, beer brewing equipment, motorised satellite dish, power tools when bored with TV, not tomention the hydrophonic garden.

 

[Rockingit]

40A is a realistic load when you consider the 1000watt hi-fi, 54" flat screen tV, smart everything, couple of 2kW heaters, beer brewing equipment, motorised satellite dish, power tools when bored with TV, not tomention the hydrophonic garden.

Two batches of Somerset cider, gurgling away quite happily, no more juice required...

In fact, must be almost time to bottle and sample. Or maybe sample to the bottom.