Multiple Earthed Neutrals (MENs)

Q: Can I have multiple earthed neutrals (MENs) in sheds and outbuildings?

A: Yes. Please read the following notes in conjunction with the scenario depicted in the diagram below.

Notes

This installation incorporates a main switchboard and three distribution boards in separate outbuildings.

At the main switchboard and distribution boards 1 and 2, a MEN connection is required as each earth bar is connected to an independent earth electrode and there is no running earthing conductor.

There is no MEN connection at distribution board 3, as the earthing is connected directly to the installation earthing system, via a running earth in the sub-main.

The method of earthing a distribution board in an outbuilding must comply with the system described above (as per the diagram).

The neutral conductor supplying distribution board 2 cannot rely on a terminal at distribution board 1 and must be continuous to distribution board 2. One method to achieve this is via a soldered tee joint.

Wiring Rules clauses (specific to this diagram):

• 1.4.66 Definition of the MEN system
• 5.3.3 Size of Earthing Conductors
• 5.3 Main Earthing Conductors
• 5.5.3 Earthing in Outbuildings and Detached Portions of an Electrical Installation