Earth rods and outbuildings

[Brummiesparky]

Came across an existing TNS installation with earth rod fitted presumably no cable sheath earth and 100ma s type as main incomer and 30ma trip for rest of circuits.
The out building is fed via 30ma and cable enclosed in steel conduit which seems to provide the earth in outbuilding so earth loop is very high, and to add to the mix there is a water supply in the out building.
Should another earth rod be installed for the outhouse and disconnect existing earth supply from house rod?
Thanks in advance

 

[telectrix]

might be an idea to use the existing earthing arrangement and add a rod at the outbuilding. i'd maybe call that TN-S/Tel.

 

[Deleted member 26818]

Don’t have to necessarily.
How far from the house is the outbuilding?
If it’s a long way, then it might be better to use separate rods so as to reduce any differences in potential.
Don’t necessarily have to disconnect the house earthing from the outhouse, could just add a rod at the outhouse and perhaps improve the Zs overall.

 

[westward10]

Why is the Zs high because it uses the conduit as a cpc. What is high, conduit if sound should provide a good fault path.

 

[Octopus]

I would be doing some basic dead tests .................. to confirm whether of not the existing set up has issues...

 

[Nigel]

What is the Ze compared to the Zs at the outbuilding?

 

[Daniel Oake]

Don’t have to necessarily.
How far from the house is the outbuilding?
If it’s a long way, then it might be better to use separate rods so as to reduce any differences in potential.
Don’t necessarily have to disconnect the house earthing from the outhouse, could just add a rod at the outhouse and perhaps improve the Zs overall.

What would you say is an acceptable distance to an outhouse/shed before you would install an earth rod (disregard Zs figures, just curious on what distance you would find to be reasonable without calculating figures etc.)

 

[Nigel]

What would you say is an acceptable distance to an outhouse/shed before you would install an earth rod (disregard Zs figures, just curious on what distance you would find to be reasonable without calculating figures etc.)

That question has no answer. In actual fact I would love to know your reasoning behind such a qurstion.

 

[Daniel Oake]

That question has no answer. In actual fact I would love to know your reasoning behind such a qurstion.

If i don't ask the questions then how will I learn, it's why I follow this forums posts; I wasn't trying to come across as being funny, i just figured someone might know something I don't

 

[bigspark17]

If that water pipe in the outbuilding is extraneous then i would say the conduit is inadequate for main bonding!

 

[Deleted member 26818]

What would you say is an acceptable distance to an outhouse/shed before you would install an earth rod (disregard Zs figures, just curious on what distance you would find to be reasonable without calculating figures etc.)

About 5m.