Main earthing terminal query.

[Derlyn]

Hi All

Regulation 6.11.4

"Where conductors from more than one supply are connected to the main earthing terminal, each conductor connected to the main earthing terminal shall be able to be disconnected individually without having to disturb any of the other earthing conductors, irrespective of the number of supplies."

My queries are:

1. What is meant by " from more than one supply " ?
2. Does a single phase domestic installation have one or more supplies ?

Derlyn

[GCE]

Hi

A domestic installation could have more than one supply - Generator , inverter , solar inverter etc .
The same goes with bigger installations and in addition you could have 2 transformers of say 800Kva each on a 1,6 Mva supply

[Derlyn]

Hi

Let me re-phrase my query.

Is the above regulation relevant on an installation with only one supply ? ie. single phase domestic installation with no generator, inverter, pv's involved.

The reason I am asking is that certain inspectors insist that each earth continuity conductor coming into the DB, be assigned it's own connection slot on the earth bar, irrespective of the number of supplies. They refer to the above regulation.

I have yet to buy a DB that has enough slots on the earth or neutral bars to do this.

Derlyn

[GCE]

Hi

I have seen that argument and am not convinced that it is correct - The code does refer to maintaining the continuity through out the installation and that disconnecting one earth should not disturb the rest .6.1.9 points that way but I dont believe that they mean in a DB .
If you look at 6.6.1.12 it could be argued that if more than 1 earth is on a terminal it cannot be easily disconnected - They also often referred to tampered with

In my opinion it is a grey area and they should not be failing it if they are under 4 sqmm -

We have taught our guys one wire per terminal , live, earth and neutral and to wire from left to right in order.Makes it easy when you come for a fault , If it is CB 3 then it will be earth 3 and neutral 3



Neutrals over 4sqmm is str forward in 6.6.1.11 and not a grey area


6.1.9 The continuity of neutral and earth circuits shall be ensured at all
times, and, except where the luminaire is used as a wireway for throughwiring,
the continuity shall not be disturbed during repair, replacement or
removal of any appliance

6.6.1.11 If a conductor of cross-sectional area exceeding 4 mm2 is used, it
shall be so installed to allow any one neutral conductor to be disconnected
without disturbing the connection of any other neutral conductor

6.6.1.12 A distribution board and the equipment mounted in or on it shall be
so positioned and arranged that any conductor can easily be disconnected
from the terminals

6.12.1.2 Earth continuity conductors shall be so arranged that they cannot
be tampered with

[Derlyn]

Thank you GCE

I will carry on as I have been for the last 40 years then.

I have never seen a problem with 2 or 3 of 1,5mm lights earths twisted together in a slot on the earth bar.
Same for the earths on plug circuits.

In all my years of fault finding, I cannot recall ever having to disconnect an earth in the DB while doing so. Neutrals yes, but not earths.

Anyway, thank you once again. Appreciated.

Derlyn

[Derlyn]

I have gone back to the regulations to get a definite answer to my original question.

The reason for this is that ALL commercially available DB's ( without exception ) are supplied with earthing terminals that have too few slots for each incoming earth continuity conductor to be assigned it's own slot. For instance: an 18 way DB is supplied with an earthing terminal containing only 5 or 6 slots and so on.

Secondly, someone accused me of issuing an invalid COC because each incoming earth continuity conductor was not assigned it's own slot on the earthing terminal. I'm talking about a domestic installation.

The accuser pointed me to reg 6.11.4

Studied this regulation again and then " the penny dropped"

This regulation refers to the Main Earthing Terminal and not the Consumer Earthing Terminal. Big difference.
The main earthing terminal is outside on the pavement in the stubby box that supplies 3 houses.
The consumer's earthing terminal is in the Main DB in the house.

I have also searched high and low to find a regulation that states the same regarding the consumer's earthing terminal, without success.

Regulation 6.11.4 now makes more sense. If, for instance the earth to house 1 is disconnected in the stubby for testing purposes, then one does not want to disturb the earth to house 2,3 and so on.

The accuser was wrong and has yet to apologize.

Cheers and peace out.

Derek

[Tang]

Hi. I think that reg. was based on cable entry boxes where guys used to use line taps for neutral earthing.