Why not connect shed earth with house earth?

[George Miles]

Why not connect shed earth with house earth?

The earth is only used in fault situation, so having the armoured cable ear thed at both ends can only make things safer, can't it?

George

diy wiki says: "When exporting an earth, the earth continuity must be maintained all the w ay through the installation from head end to submain, and into the final ou tbuilding circuits. With a locally (TT) earthed outbuilding this is not the case. Here the earth at the house end will typically be connected to the s ubmain for the purposes of giving it fault protection for the run to the ou tbuilding, however it would be isolated at the destination. Here the local earth rod connection would be used for the outbuilding."

_earth

[George Miles]

arthed at both ends can only make things safer, can't it?

way through the installation from head end to submain, and into the final outbuilding circuits. With a locally (TT) earthed outbuilding this is not t he case. Here the earth at the house end will typically be connected to the submain for the purposes of giving it fault protection for the run to the outbuilding, however it would be isolated at the destination. Here the loca l earth rod connection would be used for the outbuilding."

[Brian Gaff]

Surely though the earth is supposed, stress on n the word supposed, to be also the same as neutral line, to prevent any issues with voltages on the neutral etc. Brian

[John Rumm]

In your circumstance, there is no reason not to. I would tend to include an additional earth spike at the shed end as well, as that will probably get a lower earth impedance for both house and shed (assuming they are not right next to each other).

Not necessarily. With a TN-C-S (PME) head end, then if you export the earth you also need to export the house's equipotential zone as well.

(and a knock on implication of that is you may need to devote a core of the SWA to parallel up with the armour as an earth so that it meets the size requirements for a main bonding conductor).

Also exporting a PME earth would not be safe to do if the outbuilding had easy access to an independent earth[1]. (a supply fault that disconnected the combined protective earth and neutral conductor, could leave the "earthed" metalwork at mains potential and your local extraneous metalwork at true earth).

[1] Wooden sheds with insulated floors are probably ok, but a earth or conrete floor, or a greenhouse, or something with a rising water supply etc, can prove more problematic.

[ARW]

If you have a TT house supply then the article is not relevant. It is only relevant for PME systems.